This document summarizes a study that investigated the effect of adding sulphates to Completely Recyclable Concrete (CRC) mixtures prior to regenerating the concrete into clinker through a laboratory clinkering process. Sulphate additions ranging from 1.6-5.3% by weight were made to the CRC mixtures by adding calcium sulphate. The resulting clinkers were analyzed using X-ray diffraction to determine their mineralogy. It was found that increasing sulphate content stimulated the formation of calcium sulphate minerals like calcium langbeinite and anhydrite in the clinkers. Additionally, sulphur was found to stabilize belite formation over alite with increasing sulphate content in
Many in the oil and gas industry are now were of the effects of toxic volatile metals in process and the need to mitigate risks to personnel, process and the environment.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Treatment of wastewater from chrome plating industry by ion exchange methodeSAT Journals
Abstract In the present work an attempt has been made to evaluate the efficiency of removal Cr(VI) from chrome plating industry wastewater by using fresh and reconditioned strong base anion exchanger Tulsion A-27(MP). The Experimental data is evaluated by plotting breakthrough curves and by employing Bohart-Adams Model. The maximum removal (80%) of Cr(VI) from plating wastewater is obtained at 14cm column bed height and flowrate 1mL/min for 1144.39mg/L of influent Cr(VI) concentration. The breakthrough curves for reconditioned and fresh resins indicates that breakthrough occurs early with decrease in bed height, increase in flow rate and influent Cr(VI) concentration. Regeneration of exhausted resin is also studied by using 2M NaCl and 2M HCl. Keywords: Chromium (VI) removal; Reused Anion-exchange resin; chrome plating industry wastewater;
This paper presents an experimental result on the behavior of fly ash and slag based geopolymer concrete exposed to 5% sulphate solutions for 3.5 months of G30 and G50 which are equivalent to M30 and M50 grades respectively. The test specimens were cast and after one day rest period, half of the specimens were cured in an oven at 60°C for 24 hours and the remaining period cured in sun light until the testing is done and remaining half of the specimens were ambient cured. After 28 days the specimens were immersed in sulphates such as Na2SO4 and MgSO4 for 15, 45, 75 and 105 days then tested on 15th, 45th, 75th and 105th day according to codal procedures and the results are compared with the controlled concrete. From the test results, it is observed that the geopolymer concrete has better resistance to sulphates attack than controlled concrete.
Many in the oil and gas industry are now were of the effects of toxic volatile metals in process and the need to mitigate risks to personnel, process and the environment.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Treatment of wastewater from chrome plating industry by ion exchange methodeSAT Journals
Abstract In the present work an attempt has been made to evaluate the efficiency of removal Cr(VI) from chrome plating industry wastewater by using fresh and reconditioned strong base anion exchanger Tulsion A-27(MP). The Experimental data is evaluated by plotting breakthrough curves and by employing Bohart-Adams Model. The maximum removal (80%) of Cr(VI) from plating wastewater is obtained at 14cm column bed height and flowrate 1mL/min for 1144.39mg/L of influent Cr(VI) concentration. The breakthrough curves for reconditioned and fresh resins indicates that breakthrough occurs early with decrease in bed height, increase in flow rate and influent Cr(VI) concentration. Regeneration of exhausted resin is also studied by using 2M NaCl and 2M HCl. Keywords: Chromium (VI) removal; Reused Anion-exchange resin; chrome plating industry wastewater;
This paper presents an experimental result on the behavior of fly ash and slag based geopolymer concrete exposed to 5% sulphate solutions for 3.5 months of G30 and G50 which are equivalent to M30 and M50 grades respectively. The test specimens were cast and after one day rest period, half of the specimens were cured in an oven at 60°C for 24 hours and the remaining period cured in sun light until the testing is done and remaining half of the specimens were ambient cured. After 28 days the specimens were immersed in sulphates such as Na2SO4 and MgSO4 for 15, 45, 75 and 105 days then tested on 15th, 45th, 75th and 105th day according to codal procedures and the results are compared with the controlled concrete. From the test results, it is observed that the geopolymer concrete has better resistance to sulphates attack than controlled concrete.
Adsorption of cr (vi) from aqueous environment using neem leaves powdereSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Flotation Results of Oxidized Copper Ores of the Kalmakyr Depositijtsrd
According to preliminary calculations, oxidized copper ores in the dumps of the Kalmakyr deposit are about 107.6 million tons 01.01.2020 of which Balance ores 12.1 million tons with a Cu content of 0.8 Au 1.2 g t Ag 3.9 g t. Off balance ores 95.5 million tons with content Cu 0.3 Au 0.4 g t Ag 2 g t. Total metals copper 373 thousand tons, gold 56.6 tons, silver 246.5 tons. The total reserves of metals in the accumulated dumps are estimated at 373 thousand tons of copper, 56.6 tons of gold and 246.5 tons of silver, which is of interest primarily for non ferrous metallurgy. As a result of a set of studies carried out on samples of oxidized copper ore dumps from the Kalmakyr deposit, the following conclusions can be drawn Three methods hydrometallurgical, flotation and combined of processing oxidized copper ores of the Kalmakyr deposit have been shown experimentally and cathode copper with a content of 99.6 , a gold bearing concentrate with a gold content of 36.5 g t and silver content of 47.1 g t. Optimal modes and indicators of concentration efficiency are determined. On the basis of laboratory studies, a technology for processing oxidized copper ores of the Kalmakyr deposit has been proposed. Technological schemes for processing dumps of oxidized copper ores from the Kalmakyr deposit have been developed and recommended for implementation, the implementation of which will make it possible to obtain an estimated 6,183 tons of copper, 425 kg of gold and 707 kg of silver per year. Usenov Rasul Bovirjonovich | Yusupkhodjaev Asad Mahamatovich | Kholtursunov Farkhod Nurmatovich "Flotation Results of Oxidized Copper Ores of the Kalmakyr Deposit" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-1 , December 2020, URL: https://www.ijtsrd.com/papers/ijtsrd38006.pdf Paper URL : https://www.ijtsrd.com/engineering/mineral-and-metallurgical-engineering/38006/flotation-results-of-oxidized-copper-ores-of-the-kalmakyr-deposit/usenov-rasul-bovirjonovich
Influence of metallurgical reactions in Inconel 625 on corrosion behaviour in...Heanjia Alloys
Columbium in alloy 625 provides resistance to sensitization to alloy. Few specimens of the material, although found to be less resistant as compare to others
Removal of Chromium (VI) From Aqueous Solutions Using Discarded Solanum Tuber...inventy
Industrial polluting effluents containing heavy metals are of serious environmental concern in India. Chromium is frequently used in industries like electroplating, metal finishing, cooling towers, dyes, paints, anodizing and leather tanning and is found as traces in effluents finding their way to natural water bodies causing hazardous toxicity to the health of humans, animals and aquatic lives directly or indirectly. Many methods for the removal of Chromium such as chemical reduction, precipitation, ion exchange, electrochemical reduction, evaporation, reverse osmosis and adsorption using activated carbon etc. have been reported but all being expensive and complicated to operate. Experimental practices reveal that adsorption by agricultural and horticultural wastes are quite simple, inexpensive and efficient method. Agra is famous for Potato farming, a lot of discarded potato waste from cold storages is thrown along road side drains causing solid waste generated which either creates solid waste disposal problem or otherwise it finds way to Yamuna river resulting high BOD and posing a serious threat to the aquatic environment. For developing countries like India adsorption studies using discarded potato (Solanum tuberosum) waste from cold storages (DPWC) a solid waste as low cost adsorbent for Chromium removal was dual beneficial i.e., an ideal solution to these solid wastes disposal problem of Agra and removal of Chromium from tannery effluents and thereby saving aquatic life from Chromium contamination in Yamuna river. Keeping this in view batch experiments were designed to study the feasibility of discarded potato waste from cold storages to remove chromium (VI) from the aqueous solutions. During the study various affecting parameters, such as pH, adsorbent does, initial concentration, temperature, contact time, adsorbent grain size and start up agitation speed were optimized as 5.0, 10-20 g/l, 50 mg/l, 250C, 135 minutes, average size and 80 rpm respectively on chromium removal efficiency. Various Isotherms such as Langmuir, Freundlich, Tempkin also fitted suitably and various corresponding constants determined from these Isotherms favor and support the adsorption. Thermodynamic constants ∆G, ∆H and ∆S were found to be 0.267 KJ/mole, 0.288 KJ/mole and 0.0013 KJ/mole respectively.
Investigation of the Anodic Dissolution of Zinc in Sodium Chloride Electrolyt...IOSR Journals
The anodic dissolution of zinc electrodes in sodium chloride aqueous solution has been investigated experimentally. The effects of application of polarity reversal (PR), ultrasonic (US) enhancement, stirring, current density (CD), concentration and pH of the supporting electrolyte, and temperature of the bath were studied. The results revealed that application of PR increased the dissolution of Zn but the current was low. However, the application of US enhancement led to higher zinc dissolution accompanied with higher current efficiency (CE). The combination of US enhancement and stirring led to more dissolution of zinc. Increasing the current density and concentration of NaCl increased the dissolution of zinc and the current efficiency was almost constant. On the other hand, pH of the bath did not play a significant effect on the amount of the dissolved zinc or current efficiency. It was also observed that increasing the temperature from 10 oC to 40 oC led to a significant increase in the mass of the dissolved zinc and CE; but the increase of temperature from 40 oC to 50 or 60 oC, however, did not have a significant effect
Removal of chromium (VI) from aqueous solution using chemically modified oran...IOSR Journals
The removal of Cr (VI) from aqueous solutions onto chemically modified orange peel was studied at varying initial metal concentrations, adsorbent doses, pH and contact times. Batch experiments were carried out under optimized conditions to evaluate the adsorption capacity of the orange peel chemically modified with sodium hydroxide. The residual Cr (VI) concentrations after biosorption were analyzed by FAAS. The biosorbent was characterized by FT-IR spectroscopy and BET. The characterization of the orange peel biomass suggested the possible contribution of carboxyl and hydroxyl groups in Cr (VI) biosorption. Chemically modified orange peel exhibited more adsorption potential as compared to the raw orange peel. The biosorption efficiency of the orange peel was dependent on the pH of the Cr (VI) solution, with pH 2 being optimal. The removal rate of Cr (VI) ions increased with increase in contact time and remained constant after an equilibrium time of 180 min. The removal of Cr (VI) ions increased with increase in biosorbent concentration with the optimal adsorbent dosage at 4.0 mg/L. The increase in initial Cr (VI) ion concentration led to an increase in the percentage removal of Cr (VI). The adsorption data fitted well with the Freundlich isotherm model with R2 = 0.987 for the raw orange peel and R2 = 0.995 for the modified orange peel. The Freundlich constants Kf and n were 97.07 [mg/g (L/mg)n] and 0.79 (g/L) for the raw orange peel and 139.0 [(mg/g)(L/mg)n] and 0.815 (g/L) for modified orange peel respectively. The present study revealed that orange peel which is a low cost agricultural material could be used as an efficient sorbent for the removal of Cr(VI) from aqueous solutions and that chemical modification of the biosorbent using sodium hydroxide enhanced adsorption capacity
The alloys resistant to sulfuric acid like carpenter alloy, Hastelloy alloy G and Incoloy alloy 825 are employed to benefit in the dilution and reaction procedures.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Adsorption of cr (vi) from aqueous environment using neem leaves powdereSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Flotation Results of Oxidized Copper Ores of the Kalmakyr Depositijtsrd
According to preliminary calculations, oxidized copper ores in the dumps of the Kalmakyr deposit are about 107.6 million tons 01.01.2020 of which Balance ores 12.1 million tons with a Cu content of 0.8 Au 1.2 g t Ag 3.9 g t. Off balance ores 95.5 million tons with content Cu 0.3 Au 0.4 g t Ag 2 g t. Total metals copper 373 thousand tons, gold 56.6 tons, silver 246.5 tons. The total reserves of metals in the accumulated dumps are estimated at 373 thousand tons of copper, 56.6 tons of gold and 246.5 tons of silver, which is of interest primarily for non ferrous metallurgy. As a result of a set of studies carried out on samples of oxidized copper ore dumps from the Kalmakyr deposit, the following conclusions can be drawn Three methods hydrometallurgical, flotation and combined of processing oxidized copper ores of the Kalmakyr deposit have been shown experimentally and cathode copper with a content of 99.6 , a gold bearing concentrate with a gold content of 36.5 g t and silver content of 47.1 g t. Optimal modes and indicators of concentration efficiency are determined. On the basis of laboratory studies, a technology for processing oxidized copper ores of the Kalmakyr deposit has been proposed. Technological schemes for processing dumps of oxidized copper ores from the Kalmakyr deposit have been developed and recommended for implementation, the implementation of which will make it possible to obtain an estimated 6,183 tons of copper, 425 kg of gold and 707 kg of silver per year. Usenov Rasul Bovirjonovich | Yusupkhodjaev Asad Mahamatovich | Kholtursunov Farkhod Nurmatovich "Flotation Results of Oxidized Copper Ores of the Kalmakyr Deposit" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-1 , December 2020, URL: https://www.ijtsrd.com/papers/ijtsrd38006.pdf Paper URL : https://www.ijtsrd.com/engineering/mineral-and-metallurgical-engineering/38006/flotation-results-of-oxidized-copper-ores-of-the-kalmakyr-deposit/usenov-rasul-bovirjonovich
Influence of metallurgical reactions in Inconel 625 on corrosion behaviour in...Heanjia Alloys
Columbium in alloy 625 provides resistance to sensitization to alloy. Few specimens of the material, although found to be less resistant as compare to others
Removal of Chromium (VI) From Aqueous Solutions Using Discarded Solanum Tuber...inventy
Industrial polluting effluents containing heavy metals are of serious environmental concern in India. Chromium is frequently used in industries like electroplating, metal finishing, cooling towers, dyes, paints, anodizing and leather tanning and is found as traces in effluents finding their way to natural water bodies causing hazardous toxicity to the health of humans, animals and aquatic lives directly or indirectly. Many methods for the removal of Chromium such as chemical reduction, precipitation, ion exchange, electrochemical reduction, evaporation, reverse osmosis and adsorption using activated carbon etc. have been reported but all being expensive and complicated to operate. Experimental practices reveal that adsorption by agricultural and horticultural wastes are quite simple, inexpensive and efficient method. Agra is famous for Potato farming, a lot of discarded potato waste from cold storages is thrown along road side drains causing solid waste generated which either creates solid waste disposal problem or otherwise it finds way to Yamuna river resulting high BOD and posing a serious threat to the aquatic environment. For developing countries like India adsorption studies using discarded potato (Solanum tuberosum) waste from cold storages (DPWC) a solid waste as low cost adsorbent for Chromium removal was dual beneficial i.e., an ideal solution to these solid wastes disposal problem of Agra and removal of Chromium from tannery effluents and thereby saving aquatic life from Chromium contamination in Yamuna river. Keeping this in view batch experiments were designed to study the feasibility of discarded potato waste from cold storages to remove chromium (VI) from the aqueous solutions. During the study various affecting parameters, such as pH, adsorbent does, initial concentration, temperature, contact time, adsorbent grain size and start up agitation speed were optimized as 5.0, 10-20 g/l, 50 mg/l, 250C, 135 minutes, average size and 80 rpm respectively on chromium removal efficiency. Various Isotherms such as Langmuir, Freundlich, Tempkin also fitted suitably and various corresponding constants determined from these Isotherms favor and support the adsorption. Thermodynamic constants ∆G, ∆H and ∆S were found to be 0.267 KJ/mole, 0.288 KJ/mole and 0.0013 KJ/mole respectively.
Investigation of the Anodic Dissolution of Zinc in Sodium Chloride Electrolyt...IOSR Journals
The anodic dissolution of zinc electrodes in sodium chloride aqueous solution has been investigated experimentally. The effects of application of polarity reversal (PR), ultrasonic (US) enhancement, stirring, current density (CD), concentration and pH of the supporting electrolyte, and temperature of the bath were studied. The results revealed that application of PR increased the dissolution of Zn but the current was low. However, the application of US enhancement led to higher zinc dissolution accompanied with higher current efficiency (CE). The combination of US enhancement and stirring led to more dissolution of zinc. Increasing the current density and concentration of NaCl increased the dissolution of zinc and the current efficiency was almost constant. On the other hand, pH of the bath did not play a significant effect on the amount of the dissolved zinc or current efficiency. It was also observed that increasing the temperature from 10 oC to 40 oC led to a significant increase in the mass of the dissolved zinc and CE; but the increase of temperature from 40 oC to 50 or 60 oC, however, did not have a significant effect
Removal of chromium (VI) from aqueous solution using chemically modified oran...IOSR Journals
The removal of Cr (VI) from aqueous solutions onto chemically modified orange peel was studied at varying initial metal concentrations, adsorbent doses, pH and contact times. Batch experiments were carried out under optimized conditions to evaluate the adsorption capacity of the orange peel chemically modified with sodium hydroxide. The residual Cr (VI) concentrations after biosorption were analyzed by FAAS. The biosorbent was characterized by FT-IR spectroscopy and BET. The characterization of the orange peel biomass suggested the possible contribution of carboxyl and hydroxyl groups in Cr (VI) biosorption. Chemically modified orange peel exhibited more adsorption potential as compared to the raw orange peel. The biosorption efficiency of the orange peel was dependent on the pH of the Cr (VI) solution, with pH 2 being optimal. The removal rate of Cr (VI) ions increased with increase in contact time and remained constant after an equilibrium time of 180 min. The removal of Cr (VI) ions increased with increase in biosorbent concentration with the optimal adsorbent dosage at 4.0 mg/L. The increase in initial Cr (VI) ion concentration led to an increase in the percentage removal of Cr (VI). The adsorption data fitted well with the Freundlich isotherm model with R2 = 0.987 for the raw orange peel and R2 = 0.995 for the modified orange peel. The Freundlich constants Kf and n were 97.07 [mg/g (L/mg)n] and 0.79 (g/L) for the raw orange peel and 139.0 [(mg/g)(L/mg)n] and 0.815 (g/L) for modified orange peel respectively. The present study revealed that orange peel which is a low cost agricultural material could be used as an efficient sorbent for the removal of Cr(VI) from aqueous solutions and that chemical modification of the biosorbent using sodium hydroxide enhanced adsorption capacity
The alloys resistant to sulfuric acid like carpenter alloy, Hastelloy alloy G and Incoloy alloy 825 are employed to benefit in the dilution and reaction procedures.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Proposed mac protocol for reduce energy consumption over wsn networkeSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Applying edge density based region growing with frame difference for detectin...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Global issue based power generation expansion planning for a power systemeSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
The common challenges of mobile internet for up coming generationeSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Design of wheelchair using finger operation with image processing algorithmseSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
20160219 - F. Grati - Toma - Maternal MalignanciesRoberto Scarafia
Origin of cfDNA testing (Synonyms – NIPT or NIPS) for fetal aneuploidies
Performances of cfDNA testing for fetal aneuploidies
Maternal malignancies as a possible source for false positive cfDNA results
How to detect when the cause of FP result is a maternal malignancy
Implications for genetic counseling
Accelerted testing of deteriorated concrete structures due to carbonationeSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Effect of mineral admixtures on characteristics of high strength concreteeSAT Journals
Abstract
There is great need to conserve all the natural resources. The various steps to be adopted in the direction that includes minimization of production of energy consuming materials and heavy utilization of industrial by-products. High strength concrete can be produce using such materials like fly ash, slag and silica fumes. In many countries, these materials are already used in manufacturing of concrete. Some of these material can be used as replacement for cement. Ultimately it results in the reduction of the cost manufacturing of concrete and reduces environmental pollution. To study the effect of mineral admixtures such as fly ash, slag and silica fume on mechanical properties of high strength concrete under the uniaxial compression and split tensile, experimental studies have been conducted. The cement was replaced by 5%, 10%, 15% and 20% with fly ash and slag respectively. The compressive strength and split tensile test were conducted on concrete specimen with different percentages of fly ash and slag at age of 7 days, 28 days and 56 days. This study shows that materials used in this experiment are suitable for HSC.
Keywords: environmental pollution, fly ash, slag and silica fumes
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
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Sulphates in completely recyclable concrete and their effect on the clinker mineralogy
1. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 03 Special Issue: 13 | ICNTCC-2014 | Sep-2014, Available @ http://www.ijret.org 142
SULPHATES IN COMPLETELY RECYCLABLE CONCRETE AND
THEIR EFFECT ON THE CLINKER MINERALOGY
Mieke De Schepper1
, Eleni C. Arvaniti2
, Klaartje De Buysser3
, Isabel Van Driessche4
, Nele De Belie5
1
Magnel Laboratory for Concrete Research, Department of Structural Engineering, Ghent University, Ghent, Belgium
2
Magnel Laboratory for Concrete Research, Department of Structural Engineering, Ghent University, Ghent, Belgium
3
SCRiPTS, Department of Inorganic and Physical Chemistry, Ghent University, Ghent, Belgium
4
SCRiPTS, Department of Inorganic and Physical Chemistry, Ghent University, Ghent, Belgium
5
Magnel Laboratory for Concrete Research, Department of Structural Engineering, Ghent University, Ghent, Belgium
Abstract
Although concrete is a durable material, it has a big impact on the environment due to its high production volumes. This impact is
mostly related to the consumption of virgin raw materials, the production of waste and the emission of carbon dioxide. To
optimize the recycling opportunities of concrete, Completely Recyclable Concrete is designed as a raw material for clinker
production, without the need for ingredient adjustments. However, CRC concrete constructions may be exposed to environments
rich in chlorides, sulphates and other ions, affecting the clinkering process of CRC rubble. Therefore, it is important to know the
effect of these ions on the mineralogy of CRC clinker. In this study the effect of sulphate additions to CRC raw meals on the final
clinker mineralogy was studied by XRD/Rietveld analysis. It was found that an increasing sulphate content stimulates the
formation of CaO containing sulphates such as calcium langbeinite and anhydrite. Additionally SO3 was found to stabilize belite
at the expense of alite.
Keywords: Cement clinkering, Sulphates, X-ray diffraction
--------------------------------------------------------------------***----------------------------------------------------------------------
1. INTRODUCTION
Since the first industrial cement was produced in the middle
of the 19th
century, concrete has become the most popular
building material. Although it is a durable material, concrete
has a big impact on the environment due to its high
production volumes. Besides the use and the generation of
enormous amounts of natural resources and waste
respectively, the impact on global warming should equally
be considered. The cement industry is estimated to emit
about 5-7% of the global CO2 emissions. For these reasons
many studies in the field of concrete research focus on the
recycling of solid waste in concrete. Solid waste can be used
as concrete aggregate (e.g. slags, glass, concrete, …),
cementitious binder (e.g. slags, bottom and fly ash, silica
fume, …) or raw material for clinker production (e.g. slags,
bottom or fly ash, mining waste, refinery residues, …). Most
of the recycling opportunities, however, often arise from the
search for new synergies between usually unrelated partners.
Also, recycled products still suffer from a low acceptability
by a lack of trust in the quality of these products and in
some cases by the higher cost of recycled materials
compared to natural materials.
To take recycling to a higher level, products could be
‘designed for reincarnation’ according to the Cradle-to-
Cradle concept promoted by McDonough and Braungart.
Applying this idea on the production of concrete, it is easy
to notice that the raw materials used for concrete and cement
production share common base components. Hence the idea
emerged to design a Completely Recyclable Concrete
(CRC) which can be used as the only ingredient for cement
production after its service life. In order to make CRC a
valuable technical resource for cement production, without
need for ingredient adjustments, the concrete mixture should
be chemically equivalent to a traditional cement raw meal.
The primary ingredient for CRC is limestone aggregate as a
source for CaO, the main ingredient for Portland cement
production. Besides natural raw materials, such as limestone
and porphyry aggregate, industrial by-products like fly ash
and copper slag are preferably used for CRC production.
The degradation of a CRC structure can affect the future
clinkering process of the CRC rubble and thus its
regenerated clinker. Carbonation will mainly affect the CO2
emissions during the production of the regenerated cement.
Since this CO2 was captured from the atmosphere during the
life cycle of concrete, this additional CO2 release can be
considered neutral in a life cycle assessment. However, the
effect of the permeation of acids and salts (alkalis, Cl-
,
SO4
2-
, Mg2+
) in CRC on the regenerated cement, should be
considered differently. Their effect may be positive or
negative, depending on the concentration. For all of these
components, proper dilution might thus be required to avoid
problems during the clinkering process or in the final
cement. In this study the effect of sulphate additions on the
clinker mineralogy was assessed using XRD/Rietveld
analysis.
2. THEORETICAL BACKGROUND
The effect of sulphur on the clinkering process is related to
the alkalis present, and both will participate in cycles of
evaporation and condensation in the clinker kiln [1]. The
2. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 03 Special Issue: 13 | ICNTCC-2014 | Sep-2014, Available @ http://www.ijret.org 143
sulphates, originating from the raw materials or the fuels,
introduced in the clinkering process must eventually appear
in one of the three output streams: clinker, cement kiln dust
or gaseous emissions. As for the chlorides, also sulphate
may be retained in the kiln as annular deposits, and
contribute to the formation of kiln rings, interrupting the
normal downslope flow of the cement raw meal.
Alkalis affect the clinkering process by modifying the
physicochemical properties of the melt, and may have an
adverse effect on the phase composition of the clinker [2]. In
the presence of sulphur, the volatility of the alkali during
clinker formation is reduced. The alkali sulphates hereby
present in the melt can decrease its viscosity, but even a
small stoichiometric excess of alkali oxide over SO3
increases it. A low viscosity of the melt is favoured as it
stimulates the formation of alite by accelerating dissolution
and diffusion through the liquid of lime and belite.
When the molar SO3/(K2O+Na2O) are in balance, almost all
of the sulphur and alkalis are present in the clinker as alkali
sulphates (arcanite (K2SO4), aphthitalite (K3Na(SO4)2,
thenardite (Na2SO4)), and very little of the sulphate or
alkalis can be incorporated in the clinker phases. A
separated liquid phase is formed in the burning zone, which
is immiscible with the normal aluminate/ferrite liquid phase
[1]. If alkalis are present in the excess of sulphate, the
excess Na2O and K2O is available to be incorporated in the
clinker phases, particularly in C3A. The latter results in the
formation of so called ‘alkali aluminate’, or orthorhombic
C3A, which is more reactive compared to cubic C3A and can
result in faster setting times. If there is an excess of sulphate
present, potassium sulphate will associate with calcium
sulphate to form calcium langbeinite. The occurrence of
anhydrite in the cement clinker is related to both the SO3
and alkali (especially K2O) content.
3. MATERIALS & METHODS
3.1 Mix Design
Calcium sulphate was added to the CRC mixtures to
simulate the effect on the clinkering process of using CRC
from a construction that suffered sulphate attack. It is
difficult to find appropriate SO3 concentrations since a
considerable scatter on the results is expected. The
degradation process starts at the surface of the concrete by
crack propagation, which is initiated by the formation of
ettringite and other expansive products. The concentrations
are thus depending on the ratio of the exposed surface to the
concrete volume and the SO3 contents will be diluted in the
concrete matrix.
In a study of the sulphate ingress in mortar samples
produced with Portland cement, conducted by Schmidt et al.
[3], the sulphate concentrations as a function of depth were
studied. The effect of the sulphate ingress was observed up
to about 5 mm for exposure times of 56 and 270 days. In
that zone, the sulphate concentrations measured vary with
the concentration of the sulphate solution and the exposure
time. The SO3 concentrations varied from 5 to 20 wt% in
case the mortar samples were exposed to a 44 g/l Na2SO4
solution (high concentration). In Weritz et al. [4] different
concrete cores obtained from sewage treatment plants that
suffered sulphate attack were analysed for their sulphate
content. Although the zones with affected sulphate
concentrations were larger, up to 15 mm, the measured
sulphate concentrations were lower, up to 6 wt%.
Different amounts of CaSO4 were added to CRC raw meals,
before starting the laboratory clinkering process as described
in 3.2. The studied range of sulphate content in the CRC raw
meals was 1.6-5.3 wt% (see Table 1). The chemical
compositions of the produced raw meals and the regenerated
clinkers are given in Table 1 and Table 2 respectively. In
table 2 it is seen that a significant amount of SO3 is lost as
gaseous emission in the clinkering process, as the measured
SO3 content of the clinker is significantly lower compared to
the expected SO3 content.
Table 1: Chemical composition of the produced CRC raw
meals with different amounts of CaSO4 added (wt%)
Oxide CRC 1.6 CRC 1.9 CRC 3.2 CRC 5.3
CaO 44.4 44.7 44.3 44.3
SiO2 14.1 14 13.7 13.0
Al2O3 3.3 3.0 3.0 2.9
Fe2O3 2.1 1.9 1.9 1.8
MgO 1.3 1.2 1.2 1.2
Na2O 0.08 0.06 0.07 0.06
K2O 0.42 0.39 0.39 0.37
SO3 1.6 1.9 3.2 5.3
Cl-
0.018 0.045 0.016 0.017
LOI*
31.8 32.2 31.2 30.2
* LOI = Loss On Ignition
Table 2: Chemical composition of the regenerated clinkers
with different amounts of CaSO4 added (wt%)
Oxide CRC 1.6 CRC 1.9 CRC 3.2 CRC 5.3
CaOa
65.1 65.9 64.4 63.5
SiO2 21.6 21.5 21.1 19.8
Al2O3 4.7 4.1 4.3 4.2
Fe2O3 3.3 2.8 2.9 2.9
MgO 1.9 1.8 1.8 1.8
Na2O 0.11 0.09 0.11 0.11
K2O 0.26 0.28 0.38 0.41
SO3 0.9 1.1 2.0 4.4
Cl-
<0.005 <0.005 <0.005 <0.005
Exp.
SO3
*
2.3 2.9 4.7 7.6
a
The CaO contents were calculated from the raw material
composition by exclusion of the LOI
*
Expected SO3 content, calculated from the raw material
sulphate content by exclusion of the LOI
3.2 The Cement Regeneration Process
CRC rubble from compressive strength tests was used for
the preparation of the cement raw meal. Before grinding the
concrete in a planetary ball mill, it was broken in a jaw
crusher (resulting particle size <10 mm). After 3 minutes
milling of the cement raw meal at 300 rpm, the CaSO4 was
3. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Special Issue: 13 | ICNTCC-2014 | Sep-2014, Available @ http://www.ijret.org 144
added. The adapted raw meal was subsequently milled for 1
minute and the resulting powders were mixed with water to
form a paste that was brought into a perforated PVC-plate.
By drying, at least 1 day at room temperature or 2 hours at
60 °C, small tablets (d = 5 mm, h = 5 mm) were formed.
After removing the tablets from the perforated plate, a raw
meal was ready to be sintered.
A high temperature electric furnace (Carbolite BLF 1800)
was used for simulating the burning process. The raw meals
were gradually (10 °C/min) heated up to 1450 °C followed
by a dwell time of 60 min. After burning, the clinkers were
immediately air-cooled by removal from the furnace.
3.3 XRD Analysis
The fired clinkers were prepared for XRD analysis by
crushing the pellets to pass a 500 µm sieve in a mortar and
Figure 1: Observed XRD patterns of the SAM extractions
obtained from the CRC clinker with varying SO3 contents
pestle, followed by fine grinding in a water-free ethanol
medium in a planetary ball mill to reduce the clinker particle
size distribution below a d50 of 10 µm. The ethanol grinding
medium was immediately evaporated in a rotary evaporator
to minimize carbonation of the suspended clinker powder.
The XRD data were collected on a Thermo Scientific ARL
X’tra Diffractometer equipped with a Peltier cooled
detector.
To increase the accuracy and lower the detection limits of
the quantitative phase analysis by XRD, selective
dissolution methods were used to reduce reflection peak
overlap in the XRD patterns and concentrate the
characteristic residue fraction. A solution of salicylic acid in
methanol (SAM extraction) was used to dissolve the clinker
calcium silicates and a solution of KOH and sucrose in H2O
(KOSH extraction) to remove mainly the C3A, C4AF and
soluble sulphate phases. The dissolution procedures are
described elsewhere [5]. Additionally, the internal standard
approach was selected for absolute phase quantification and
estimation of the amorphous or non-identified phase content
by XRD analysis [6, 7]. A 10 wt% ZnO internal standard
was added to the untreated clinker powder. Finally the
4. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Special Issue: 13 | ICNTCC-2014 | Sep-2014, Available @ http://www.ijret.org 145
powders were side-loaded into sample holders to reduce
preferred orientation effects.
Samples were measured in θ-2θ geometry over an angular
range of 5-70 °2θ (CuKα radiation) using a 0.02 °2θ step
size and 1 s/step counting time. Topas Academic V4.1
software was used for Rietveld refinement [8]. The phase
quantification routine for the fired clinkers initiated with the
identification of major and minor phases in the SAM and
KOSH treated samples. Subsequently, peak shape and unit
cell parameters of the major clinker phases were refined and
used as fixed input for the final quantitative phase analysis
of the untreated clinker samples as described in Le Saoût et
al. [9]. Also the clinker C3A/C4AF weight ratio was taken
from the analysis of the SAM treated residue. This
procedure strongly reduces parameter correlation during
refinement of the untreated sample. Overall, the refined
parameters were the measurement specific or global zero
error and cosine Chebyshev function of 12 polynomial terms
and the phase specific scale factors, unit cell parameters and
Lorentzian peak shape broadening parameters.
4. RESULTS
The effect of the sulphate additions on the clinker
mineralogy was studied by XRD/Rietveld analysis. The
XRD/Rietveld analysis of the SAM extraction was used to
evaluate the distribution of the sulphate phases qualitatively.
Quantitative analysis from XRD/Rietveld analysis of the
whole clinker was not possible for all sulphate phases due to
their presence under the detection limits related to their low
concentrations. The effect of sulphate additions on the major
phases was studied quantitatively by XRD/Rietveld analysis
of the whole clinker sample.
4.1 Distribution of the Sulphate Phases
The XRD patterns obtained from the SAM extractions are
shown in Figure 1. For the lower sulphate concentrations
(CRC 1.6 and CRC 1.9), limited amounts of sulphates are
found, namely arcanite and Ca-langbeinite. For higher
sulphate concentrations (CRC 3.2 and CRC 5.3), significant
amounts of the calcium sulphate anhydrite were observed.
Some H2O bearing calcium sulphate phases (bassanite
(CaSO4.1
/2H2O)) were observed. The uptake of this water
probably occurred during the sample preparation. No
thenardite, and only a limited amount of aphthitalite was
found present in the CRC clinkers. The absence of
significant amounts of sodium sulphates can be expected
due to the low sodium concentrations of the clinkers.
For both calcium langbeinite and bassanite, the reflections
slightly shift in the 2θ range. Rietveld analysis of the XRD
patterns indeed showed that the cell parameters of both
phases are affected by the sulphate concentration of the
clinker. Probably the sulphate concentration slightly affects
the composition of the phases and thus the cell parameters.
In case of bassanite also the water content might be
responsible for the observed shift.
4.2 Effect on the Major Clinker Phases
The results of the XRD/Rietveld analysis of the whole
clinker samples are presented in Table 3. The formation of
alite seems to be stimulated by a lower viscosity of the melt
when the sulphate concentration was about 1.1% (CRC 1.9).
A further increase of the sulphate concentrations resulted in
the stabilisation of belite due to the uptake of SO3.
Table 3: Mineralogical composition of the regenerated
clinkers with different amounts of CaSO4 added [wt%] by
XRD/Rietveld analysis
Mineral CRC 1.6 CRC 1.9 CRC 3.2 CRC 5.3
Alite 65.6 71.2 67.2 60.7
Belite 16.3 11.2 21.7 22.9
Aluminate 1.3 1.1 1.0 0.8
Ferrite 11.5 9.7 9.2 9.4
Anhydrite 4.2
Calcite 0.7 0.7 0.8 1.4
Periclase 0.4 0.1 0.1 0.6
Other 4.3 6.1
In Table 4, the distribution of the four main clinker phases
obtained by XRD/Rietveld analysis are compared with the
potential mineralogy as calculated with the modified Bogue
formulas. The increased amount of alite observed for
CRC 1.9 is also obtained within the modified Bogue
calculations. Since these calculations do not take into
account the effect of alkali and/or sulphates on the viscosity
of the melt and thus the burnability of the clinker, the
increased alite content might be a result of rather limited
changes in raw meal composition. In the end it is probably a
combined effect of SO3 on the melt viscosity and the raw
meal composition that explains the increased alite content
in the clinker. The stabilisation of belite by the incorporation
of SO3 is taken into account in the modified Bogue
calculation. This effect is seen in the calculations for the
CRC clinkers with the highest SO3 concentration (CRC 3.2
and CRC 5.3), having a significantly higher belite content at
the expense of alite.
Table 4: Mineralogical composition of the regenerated
clinkers with different amounts of CaSO4 added [wt%] by
XRD/Rietveld analysis
Mineral CRC 1.6 CRC 1.9 CRC 3.2 CRC 5.3
XRD – normalized for four main clinker phases
Alite 69.3 76.5 67.8 64.8
Belite 17.2 12.0 21.9 24.5
Aluminate 1.3 1.1 1.0 0.8
Ferrite 12.1 10.4 9.3 0.8
Modified Bogue – normalized for four main clinker phases
Alite 73.9 82.7 74.3 62.1
Belite 10.2 3.6 10.7 20.9
Aluminate 5.0 4.5 5.4 6.8
Ferrite 10.9 9.2 9.5 10.1
5. DISCUSSION
From literature it was concluded that the effect of an
increasing sulphate content is highly depending on the alkali
5. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Special Issue: 13 | ICNTCC-2014 | Sep-2014, Available @ http://www.ijret.org 146
content. Since the alkali content of the studied clinkers is
rather low, it was observed that an increasing sulphate
content resulted in the formation of more CaO containing
sulphates such as calcium langbeinite and anhydrite. The
reasoning could be made that the consumption of CaO by
the formation of calcium langbeinite and anhydrite will
reduce the alite formation since less CaO is available. The
latter is however not expected in this study, as the sulphates
are added as calcium sulphate. Since a significant amount of
sulphate was lost due to emissions in the clinkering process,
a limited enrichment of the CaO content is more likely.
The experimental results obtained in the present study (low
alkali content) showed that the effect of SO3 concentrations
up to 2% on the clinker mineralogy are limited. For sulphate
concentrations up to 4.4%, the high SO3 content seemed to
stabilize belite at the expense of alite. This effect is certainly
not favoured, although the resulting alite contents are
certainly acceptable for a modern clinker, since the alite
content of the clinker to start from was rather high.
In practice, the sulphate content of a clinker raw meal
should be limited in order to avoid clogging of material on
the sides of the clinker kiln. Depending on the kiln
installation, the sulphate content of the final clinker should
be limited to 1.1-1.4% [10]. These more strict practical
limitations will also avoid problems related to mineralogy as
discussed above. Additionally, in practice, a stoichiometric
balance is imposed on the sulphate and alkali content,
expressed as the Degree of Sulphatisation (DoS) [10]:
DoS =
77.41 ∙ 𝑤𝑡%(𝑆𝑂3)
(𝑤𝑡%(𝑁𝑎2 𝑂) + 0.658 ∙ 𝑤𝑡(𝐾2 𝑂)
calculated using the chemical analysis of the final clinker.
DoS levels between 80 and 120 wt% are recommended to
avoid damage to the kiln system. In case of the current
study, the alkali contents are rather low, resulting in an
imbalance between the sulphates and alkali. In order to meet
practical requirements, the SO3 and alkali content should
thus be decreased or increased respectively.
Finally, it should be noted that the behaviour of alkalis and
sulphates in the real clinkering process could not be
simulated in the static furnace used. This study only showed
how an increasing sulphate content (with constant alkali
content) affects the clinker mineralogy. The effect of an
increasing sulphate content of a cement raw meal on the
clinker processing of a real kiln is expected to result in more
strict limitations. An optimisation of the SO3/(K2O+Na2O)
balance in case of the studied CRC raw meals will be
required. In the end it can be concluded that the use of
concrete that suffered sulphate attack will not harm the
clinkering process, if properly diluted.
6. CONCLUSION
When using CRC as cement raw material, the permeated
acids and salts in deteriorated concrete will have an effect
on the clinkering process. In this study the effect of sulphate
additions to a CRC raw meal on the regenerated clinker
mineralogy was studied by means of XRD/Rietveld
analysis. It was found that an increasing sulphate content
stimulates the formation of CaO containing sulphates such
as calcium langbeinite and anhydrite. Additionally it was
found that higher sulphate concentrations stabilize belite at
the expense of alite.
ACKNOWLEDGEMENTS
Financial support from the Institute for the Promotion of
Innovation through Science and Technology in Flanders
(IWT-Vlaanderen) and the Research Foundation – Flanders
(FWO) under Grant no. G087510N are gratefully
acknowledged. The authors would like to thank P. Van der
Voort for granting access to the XRD facilities.
REFERENCES
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Volume: 03 Special Issue: 13 | ICNTCC-2014 | Sep-2014, Available @ http://www.ijret.org 147
BIOGRAPHIES
Mieke De Schepper received her master
degree in civil engineering in 2009 from
Ghent University (Belgium). Currently she
is finishing her PhD on Completely
Recyclable Concrete at the Magnel
laboratory for Concrete Research (Ghent
University).
Eleni C. Arvaniti received her PhD degree
from the University of Patras (Greece) in
2009. From May 2012 until April 2014 she
was working as a post-doctoral researcher
on Completely Recyclable Concrete at the
Magnel laboratory for Concrete Research
(Ghent University).
Klaartje De Buysser received her PhD
degree from Ghent University (Belgium) in
2007. Since 2009 she is professor at the
faculty of science at Ghent University
(SCRiPTS research group). Her research
interests are transparent, conductive oxides,
thermoelectric materials and
electrospinning of ceramic fibres.
Isabel Van Driessche is professor at Ghent
University (Belgium) since 2004. She is
head of the department Inorganic and
Physical Chemistry and leads the research
group SCRiPTS, that has activities in the
broad field of solid state chemistry related
to the synthesis, properties and applications
of inorganic and ceramic materials, both as bulk and thin
films.
Nele De Belie is professor in Durability of
Cement Bound Materials at Ghent
University (UGent) since 2000. She is
technical director of the Magnel Laboratory
for Concrete Research and leads the
research group Concrete and Environment
that has activities in the broad field of
cement and concrete related to durability
and sustainability.