These slides on management of minor elements in the production of base metals were presented at the Green Processing conference. This paper explores alternative processing options for selective removal of minor elements such as arsenic so as to avoid dispersion of such toxic elements in the biosphere.
The full paper was published through AusIMM conference proceedings.
This workshop is a deliverable of TRAC project which has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement Nº777823.
Presentation 1:
On the Reactivity Mechanism of Supplementary Cementitious Materials by Alkali Activation
Yu Jin, Shenzhen Institute of Information Technology, China
Dr. Yu Jin obtained his Ph.D from Techische Universität Berlin and works currently as an associate researcher at Shenzhen Institute of Information Technology. He is now the member of GDCh Bauchemie (German Chemical Society Construction Chemistry Branch) and reviewer for some prestigious journals like Journal of the American Ceramics Society, Journal of Cleaner Production. He has published 19 journal papers, including those in Cement and Concrete Research, Journal of Cleaner Production. His research interest covers the ultlization of solid waste, alkali activated materials, latex modified cement based materials.
Hydrogenation of sugars over supported metal catalyst - effect of supportpbpbms6
A process of hydrogenation of sugars into sugar alcohol is described in presence of supported metal catalysts. Influence of support in reaction is also shown.
This workshop is a deliverable of TRAC project which has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement Nº777823.
Presentation 1:
On the Reactivity Mechanism of Supplementary Cementitious Materials by Alkali Activation
Yu Jin, Shenzhen Institute of Information Technology, China
Dr. Yu Jin obtained his Ph.D from Techische Universität Berlin and works currently as an associate researcher at Shenzhen Institute of Information Technology. He is now the member of GDCh Bauchemie (German Chemical Society Construction Chemistry Branch) and reviewer for some prestigious journals like Journal of the American Ceramics Society, Journal of Cleaner Production. He has published 19 journal papers, including those in Cement and Concrete Research, Journal of Cleaner Production. His research interest covers the ultlization of solid waste, alkali activated materials, latex modified cement based materials.
Hydrogenation of sugars over supported metal catalyst - effect of supportpbpbms6
A process of hydrogenation of sugars into sugar alcohol is described in presence of supported metal catalysts. Influence of support in reaction is also shown.
LCA based determination of energy requirement for processing and extraction of low grade copper ores by a range of alternative processes covering both hydro and pyrometallurgy. The scenarios include direct converting of ores with waste heat recovery from molten slag through dry granulation technology.
Leaching kinetics of powdered pcb of mobile phones in hno3 mediumeSAT Journals
Abstract Printed circuit board (PCB) of mobile phones is leached in nitric acid (HNO3) to extract the valuable metals present in PCB into
the leaching solution. PCB powder is characterized by XRD analysis before and after leaching to identify the metallic phases
present in it. It is found that precious metals gold (Au), silver (Ag), platinum (Pt), copper (Cu), lead (Pb), nickel (Ni) are present
in the powder PCB before leaching. The leached solution is characterized by atomic absorption spectrometer (AAS). 0.0228% Pb,
0.0448% Fe and 0.047% Cu are extracted in the solution. The leaching kinetics is also studied. Activation energy of the reaction
is calculated 23 KJ which suggest that the leaching reaction is diffusion controlled.
Keywords: PCB, Leaching Kinetics, XRD Analysis, AAS
30 Radical Things I want my Daughter to know by Heart and by SpiritCharnita Arora
<here>
In my journey as a Wellbeing Coach at Perfect Life Spot (PLS), my role is often that of a nurturer. And since most of our participants are young women, I feel like a mother. In fact, I can already imagine having a daughter someday and feeling like I already know how it feels to be a mother.
“What if I could create a life-manual of sorts; something like a clear yet precise catalog of ideas and practices to guide her…”, I have often delightfully wondered. May be even like some version of Randy Pausch’s The Last Lecture. And so, this post is a result of a delightful wandering and wondering. It emerges from my own real-time experience of being a young female entrepreneur in India navigating through life on her own terms.
Here are 30 radical things that I want my daughter to know by heart and by spirit for creating a wholesome life.
Please note that these points stand valid for all the genders.
Original post: https://medium.com/@arora.charnita/30-radical-things-i-want-my-daughter-to-know-by-heart-a7550962f03f#.j32g33xfu
Characterization and reuse avenues of bof slag as flux material in sinterIJARIIT
The present study “Characterization and Reuse avenues of BOF Slag as a flux material in sinter” are focused on waste
utilization for a sustainable growth and development. In an integrated steel plant, approximately 2-4 tonnes of wastes (including
solid, liquid and gas) are generated for every tonne of steel produced. Among all the wastes, slag generated at iron making and
steel making units are a key area of concern. With increasing capacities, the mechanism for disposal of large quantities of slag
that get generated have gained traction as the environmental issues that it could evoke could become critical for steel makers.
Over the last few years, with better understanding process there is a significant reduction in the volume of slag generated.
However, slag generation remains inevitable and emphasis on its recycling remains one of the most serious concerns that need
to be solved. Blast furnace granulated slag is a glassy aggregate and used as raw material for pozzolanic cement. But BOF
granulated slag is crystalline and less glassy phase compared to BF slag, so 100 % utilization as pozzalanic cement manufacture
is limited. Hence, alternate reuse avenues are under study at research or implementation level. The present topic is selected to
study the reuse avenues of BOF Slag as a flux material in sinter.
LCA based determination of energy requirement for processing and extraction of low grade copper ores by a range of alternative processes covering both hydro and pyrometallurgy. The scenarios include direct converting of ores with waste heat recovery from molten slag through dry granulation technology.
Leaching kinetics of powdered pcb of mobile phones in hno3 mediumeSAT Journals
Abstract Printed circuit board (PCB) of mobile phones is leached in nitric acid (HNO3) to extract the valuable metals present in PCB into
the leaching solution. PCB powder is characterized by XRD analysis before and after leaching to identify the metallic phases
present in it. It is found that precious metals gold (Au), silver (Ag), platinum (Pt), copper (Cu), lead (Pb), nickel (Ni) are present
in the powder PCB before leaching. The leached solution is characterized by atomic absorption spectrometer (AAS). 0.0228% Pb,
0.0448% Fe and 0.047% Cu are extracted in the solution. The leaching kinetics is also studied. Activation energy of the reaction
is calculated 23 KJ which suggest that the leaching reaction is diffusion controlled.
Keywords: PCB, Leaching Kinetics, XRD Analysis, AAS
30 Radical Things I want my Daughter to know by Heart and by SpiritCharnita Arora
<here>
In my journey as a Wellbeing Coach at Perfect Life Spot (PLS), my role is often that of a nurturer. And since most of our participants are young women, I feel like a mother. In fact, I can already imagine having a daughter someday and feeling like I already know how it feels to be a mother.
“What if I could create a life-manual of sorts; something like a clear yet precise catalog of ideas and practices to guide her…”, I have often delightfully wondered. May be even like some version of Randy Pausch’s The Last Lecture. And so, this post is a result of a delightful wandering and wondering. It emerges from my own real-time experience of being a young female entrepreneur in India navigating through life on her own terms.
Here are 30 radical things that I want my daughter to know by heart and by spirit for creating a wholesome life.
Please note that these points stand valid for all the genders.
Original post: https://medium.com/@arora.charnita/30-radical-things-i-want-my-daughter-to-know-by-heart-a7550962f03f#.j32g33xfu
Characterization and reuse avenues of bof slag as flux material in sinterIJARIIT
The present study “Characterization and Reuse avenues of BOF Slag as a flux material in sinter” are focused on waste
utilization for a sustainable growth and development. In an integrated steel plant, approximately 2-4 tonnes of wastes (including
solid, liquid and gas) are generated for every tonne of steel produced. Among all the wastes, slag generated at iron making and
steel making units are a key area of concern. With increasing capacities, the mechanism for disposal of large quantities of slag
that get generated have gained traction as the environmental issues that it could evoke could become critical for steel makers.
Over the last few years, with better understanding process there is a significant reduction in the volume of slag generated.
However, slag generation remains inevitable and emphasis on its recycling remains one of the most serious concerns that need
to be solved. Blast furnace granulated slag is a glassy aggregate and used as raw material for pozzolanic cement. But BOF
granulated slag is crystalline and less glassy phase compared to BF slag, so 100 % utilization as pozzalanic cement manufacture
is limited. Hence, alternate reuse avenues are under study at research or implementation level. The present topic is selected to
study the reuse avenues of BOF Slag as a flux material in sinter.
Study of corrosion control effect of H2S scavengers in drilling fluidsMutiu K. Amosa, Ph.D.
Selected environmentally benign iron compounds (synthetic magnetite and ferrous gluconate) have been evaluated as corrosion inhibitors for oil-well steel (N-80) in 50 mg/l sulphide concentration at various pH ranging from 5.5 to 11.5 and at High Temperature, High Pressure (HTHP) conditions by the weight loss method. The test temperatures were 150 °F, 275 °F and 350 °F respectively for pressures of 3 000 psi, 5 000 psi and 6 000 psi. The ferrous complex was found to be a better corrosion inhibitor compared to the synthetic magnetite. It exhibited up to 99.2% inhibition efficiency (IE) when the dose of the scavenger was doubled (i.e. when the sulphide to scavenger ratio was 1:2) irrespective of other factors such as pH, temperature and pressure. Whereas, the synthetic magnetite’s optimum inhibition efficiency (IE) was observed to be up to 75.1% only when the ratio of the sulphide to scavenger was 1:4 at the lowest pH of the experiment (pH 5.5) which is not desirable for a drilling mud. As the pH increases, the inhibition efficiency of the magnetite decreases and found to be lowest at the alkaline pH of 11.5.
The extraction of zinc(II) from zinc-plating wastewater by liquid-liquid extraction was studied using the commercial extractants di-(2-ethylhexyl)phosphoric acid (D2EHPA) and bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex® 272), as well as the ionic liquids, Trihexyltetradecylphosphonium bromide (Cyphos® 102), Trihexyltetradecylphosphonium decanoate (Cyphos® 103) and Trihexyltetradecylphosphonium bis(2,4,4- trimethylpentyl)phosphinate (Cyphos® 104), diluted in organic solvents. First, the commercial extractants and the ionic liquids with the most potential were selected based on the results from diluents, modifiers, and stripping solution screening tests. Then, the optimization of extraction and re-extraction (stripping) conditions for each extractant was achieved either by effluent pre-treatment (pH adjustment) to remove iron before liquid-liquid extraction or by adjusting the extractant-to-zinc ratio. Afterward, one commercial extractant and one ionic liquid were selected for further evaluation based on the following parameters: reusability, contact time (kinetic studies), and loading capacity.
Chemical, mineralogical and metallurgical characterization of goethite rich i...IJARIIT
In this paper the influence of structural water present in goethite rich ore fines on sinter properties like mean size, RI,
RDI, TI, AI and microstructure were studied. For this three plant sinters with different basicities (A1, A2 and A3) were
experimentally produced varying the raw mix. From the study on variable basicity, it is found that increased basicity has good
effects on the sinter properties. The desired norms of metallurgical properties for good quality sinter required for large size blast
furnace met with increased tumbler index and decreased abrasion index. The RI is also better in highly fluxed sinter A3 and the
RDI is low. All these are happening due to availability of more free lime and porosity. The mean-size of sinter also increases
with increase of basicity. The reducibility index and RDI of sinter A2 and A3 appear to be similar although there is a variation
in chemistry and basicity, this may be attributed to use of more micro-fines in raw material of sinter A3. The specific consumption
of coke rate is highest for sinter A3 is also due to more micro-fines in raw materials. From the microstructure it is found that in
sinter A1 more magnetite and less ferrites are developed in comparison to A2 and A3. The silicoferrites of calcium and
aluminium (SFCA) developed in sinter A2 and A3 are acicular in structure which provides better strength to the sinter. Also the
porosity is more in case of A2 and A3 which can accelerate the reducibility process.
About, 80% of world’s total zinc is produced through conventional hydro-metallurgical process
i.e. Roast-leach-electrolysis (RLE) process. . The process rejects iron in the form of jarosite, a crystalline and
easily filterable solid residue. jarosite contains higher concentration of toxic elements like lead, zinc, sulfur,
cadmium, chromium and copper etc. Due to these characteristics, jarosite itself is cosidered highly hazardous
material universally and has detrimental effects on environment as well as human health. Jarosite residue
collected from HZL is treated to recover different metal values. As such jarosite is a very stable matrix and all
the metals present in it is in insoluble form. Direct dissolution of different metals from jarosite matrix was found
very poor. Therefore, a combined sulfation–roasting–leaching process was developed for selective and
quantitative dissolution and recovery. Sulphuric acid roasting followed by water leaching could recover Zn, Cd
and other minor base metals quantitatively. The lead enriched in residue is recovered by leaching in brine
solution of suitable composition. Finally AAS & XRD analysis is done for characterisation of materials. From
the analysis, we conclude that after second stage brine leaching process recovery of zinc 98.58% , cadmium
99.99%, lead 99.92% and iron 86.34%.
Synthesis of citrate-capped gold nanoparticles from reduced [AuCl4 ]– on asco...UniversitasGadjahMada
Reductive adsorption of [AuCl4]-– by using ascorbic acid immobilized on Mg/Al hydrotalcite (Mg/Al HT) and synthesis of gold nanoparticles (AuNPs) from the reduced gold using sodium citrate have been conducted. Mg/Al HT was synthesized by co-precipitation method at pH 10 with molar ratio of Mg(II) and Al(III) 2:1. Ascorbic acid (AA) was then immobilized on Mg/Al HT to form hybrid of AA and Mg/Al HT (Mg/Al HT-AA). Mg/Al HT-AA was used to reductively adsorb [AuCl4]– and the formed Au(0) was extracted by using sodium citrate to form citrate-capped AuNPs. The formation of AuNPs from 100 mg/L [AuCl4]– solution removed by 60 mg Mg/Al HT-AA was optimum at pH 5.0, by using 70 mM sodium citrate and 2 h sonication time. This optimum condition was successfully applied to synthesize AuNPs from [AuCl4]– as the leaching product of gold from PCB using aquaregia
"Understanding the Carbon Cycle: Processes, Human Impacts, and Strategies for...MMariSelvam4
The carbon cycle is a critical component of Earth's environmental system, governing the movement and transformation of carbon through various reservoirs, including the atmosphere, oceans, soil, and living organisms. This complex cycle involves several key processes such as photosynthesis, respiration, decomposition, and carbon sequestration, each contributing to the regulation of carbon levels on the planet.
Human activities, particularly fossil fuel combustion and deforestation, have significantly altered the natural carbon cycle, leading to increased atmospheric carbon dioxide concentrations and driving climate change. Understanding the intricacies of the carbon cycle is essential for assessing the impacts of these changes and developing effective mitigation strategies.
By studying the carbon cycle, scientists can identify carbon sources and sinks, measure carbon fluxes, and predict future trends. This knowledge is crucial for crafting policies aimed at reducing carbon emissions, enhancing carbon storage, and promoting sustainable practices. The carbon cycle's interplay with climate systems, ecosystems, and human activities underscores its importance in maintaining a stable and healthy planet.
In-depth exploration of the carbon cycle reveals the delicate balance required to sustain life and the urgent need to address anthropogenic influences. Through research, education, and policy, we can work towards restoring equilibrium in the carbon cycle and ensuring a sustainable future for generations to come.
Natural farming @ Dr. Siddhartha S. Jena.pptxsidjena70
A brief about organic farming/ Natural farming/ Zero budget natural farming/ Subash Palekar Natural farming which keeps us and environment safe and healthy. Next gen Agricultural practices of chemical free farming.
Micro RNA genes and their likely influence in rice (Oryza sativa L.) dynamic ...Open Access Research Paper
Micro RNAs (miRNAs) are small non-coding RNAs molecules having approximately 18-25 nucleotides, they are present in both plants and animals genomes. MiRNAs have diverse spatial expression patterns and regulate various developmental metabolisms, stress responses and other physiological processes. The dynamic gene expression playing major roles in phenotypic differences in organisms are believed to be controlled by miRNAs. Mutations in regions of regulatory factors, such as miRNA genes or transcription factors (TF) necessitated by dynamic environmental factors or pathogen infections, have tremendous effects on structure and expression of genes. The resultant novel gene products presents potential explanations for constant evolving desirable traits that have long been bred using conventional means, biotechnology or genetic engineering. Rice grain quality, yield, disease tolerance, climate-resilience and palatability properties are not exceptional to miRN Asmutations effects. There are new insights courtesy of high-throughput sequencing and improved proteomic techniques that organisms’ complexity and adaptations are highly contributed by miRNAs containing regulatory networks. This article aims to expound on how rice miRNAs could be driving evolution of traits and highlight the latest miRNA research progress. Moreover, the review accentuates miRNAs grey areas to be addressed and gives recommendations for further studies.
Artificial Reefs by Kuddle Life Foundation - May 2024punit537210
Situated in Pondicherry, India, Kuddle Life Foundation is a charitable, non-profit and non-governmental organization (NGO) dedicated to improving the living standards of coastal communities and simultaneously placing a strong emphasis on the protection of marine ecosystems.
One of the key areas we work in is Artificial Reefs. This presentation captures our journey so far and our learnings. We hope you get as excited about marine conservation and artificial reefs as we are.
Please visit our website: https://kuddlelife.org
Our Instagram channel:
@kuddlelifefoundation
Our Linkedin Page:
https://www.linkedin.com/company/kuddlelifefoundation/
and write to us if you have any questions:
info@kuddlelife.org
Characterization and the Kinetics of drying at the drying oven and with micro...Open Access Research Paper
The objective of this work is to contribute to valorization de Nephelium lappaceum by the characterization of kinetics of drying of seeds of Nephelium lappaceum. The seeds were dehydrated until a constant mass respectively in a drying oven and a microwawe oven. The temperatures and the powers of drying are respectively: 50, 60 and 70°C and 140, 280 and 420 W. The results show that the curves of drying of seeds of Nephelium lappaceum do not present a phase of constant kinetics. The coefficients of diffusion vary between 2.09.10-8 to 2.98. 10-8m-2/s in the interval of 50°C at 70°C and between 4.83×10-07 at 9.04×10-07 m-8/s for the powers going of 140 W with 420 W the relation between Arrhenius and a value of energy of activation of 16.49 kJ. mol-1 expressed the effect of the temperature on effective diffusivity.
UNDERSTANDING WHAT GREEN WASHING IS!.pdfJulietMogola
Many companies today use green washing to lure the public into thinking they are conserving the environment but in real sense they are doing more harm. There have been such several cases from very big companies here in Kenya and also globally. This ranges from various sectors from manufacturing and goes to consumer products. Educating people on greenwashing will enable people to make better choices based on their analysis and not on what they see on marketing sites.
Diabetes is a rapidly and serious health problem in Pakistan. This chronic condition is associated with serious long-term complications, including higher risk of heart disease and stroke. Aggressive treatment of hypertension and hyperlipideamia can result in a substantial reduction in cardiovascular events in patients with diabetes 1. Consequently pharmacist-led diabetes cardiovascular risk (DCVR) clinics have been established in both primary and secondary care sites in NHS Lothian during the past five years. An audit of the pharmaceutical care delivery at the clinics was conducted in order to evaluate practice and to standardize the pharmacists’ documentation of outcomes. Pharmaceutical care issues (PCI) and patient details were collected both prospectively and retrospectively from three DCVR clinics. The PCI`s were categorized according to a triangularised system consisting of multiple categories. These were ‘checks’, ‘changes’ (‘change in drug therapy process’ and ‘change in drug therapy’), ‘drug therapy problems’ and ‘quality assurance descriptors’ (‘timer perspective’ and ‘degree of change’). A verified medication assessment tool (MAT) for patients with chronic cardiovascular disease was applied to the patients from one of the clinics. The tool was used to quantify PCI`s and pharmacist actions that were centered on implementing or enforcing clinical guideline standards. A database was developed to be used as an assessment tool and to standardize the documentation of achievement of outcomes. Feedback on the audit of the pharmaceutical care delivery and the database was received from the DCVR clinic pharmacist at a focus group meeting.
1. Management of MinorManagement of Minor
Elements in theElements in the
Production of Base MetalsProduction of Base Metals
Sharif Jahanshahi, Warren Bruckard,
Chunlin Chen and Frank Jorgensen Mission: To progressively
eliminate waste and emissions
in the minerals cycle, while
enhancing business
performance and meeting
community expectations
2. Presentation by Sharif Jahanshahi PhD, FAusIMM
Sharif Jahanshahi has over 30 years
experience in R&D across; high temperature
processing of ferrous and base metals,
thermodynamics and kinetics of high
temperature systems, melt chemistry,
process modelling, simulation and
development
Currently consulting for leading global
players in the metallurgical industry through
Meta-Logical Solutions Pty Ltd.
Website: http://www.metalogical.solutions
Email: sharif@metalogical.solutions
3. Green Processing 2006: 5-6 June 3
BackgroundBackground
Australia exports ~ 3 millions of tpa of copper, nickel, lead and
zinc in form of concentrate and refined metals.
Base metal ores contain low levels (1- 104
ppm) of toxic/
hazardous elements (As, Sb, Bi, Cd, Hg, Se, Te…, Th, U)
Clean, coarsely-grained ore bodies becoming depleted
Ore bodies of future becoming more complex, finer-grained and
containing higher amount of minor/toxic elements.
Worldwide industry mines and process 100s million tonnes of
base metal ores each year
Accumulated mass of minor elements in biosphere is
large and could have a significant environmental impact
4. Green Processing 2006: 5-6 June 4
Industry ContextIndustry Context
Minor elements present technical and environmental problems
as well as being costly
Smelters impose treatment charges and penalty payment on
minor elements in concentrates
Governments becoming increasingly sensitive to emissions
Community pressure for more sustainable processing
Smelters setting tighter penalty specifications for minor
elements
Imperative to develop alternative treatments for
selective removal of toxic elements at the mine site
before despatch of concentrate to smelters
5. Green Processing 2006: 5-6 June 5
Options for Dealing with ToxicOptions for Dealing with Toxic
Elements in OresElements in Ores
Primarily determined by mineralogy and grain size
Occurrence - association with other elements
Distribution between phases
For widely and uniformly dispersed minor elements in mineral
phases treatment option is limited
Separation and removal in waste/residue streams produced in metal
extraction
If concentrated in discrete phases, options exists for early
removal by physical and chemical means
Having separated and concentrated the toxic elements,
consideration has to be given to their use or safe disposal
6. Green Processing 2006: 5-6 June 6
ArsenicArsenic
Is one impurity element found in most base metal ores and
concentrates
Lowers metal quality, if not removed from product metal
Contributes to health concerns during metallurgical processing
Causes environmental concerns during disposal of tailings and
wastes
High arsenic levels in an ore can make the deposit economically
unviable
Blending of high and low arsenic concentrates has been
practiced by industry. Can we continue this in the future?
7. Green Processing 2006: 5-6 June 7
Mineralogy ConsiderationMineralogy Consideration
In copper ores arsenic occurs as
Enargite (Cu3AsS4) Tennanite (3Cu2S.As2S3)
Arsenopyrite (FeAsS) Cobaltite (CoAsS)
In nickel systems
Gersdorffite (NiAsS) Niccolite (NiAs)
Arsenopyrite (FeAsS) Cobaltite (CoAsS)
Physical separation of arsenic bearing minerals from non-
arsenic bearing minerals is difficult
Similar specific gravity, non-magnetic, strongly floatable with
conventional collectors etc.
Some As minerals contain high concentration of copper and
nickel e.g. enargite (Cu3AsS4) has 48% Cu
8. Green Processing 2006: 5-6 June 8
Mineral Recovery in 1 minuteMineral Recovery in 1 minute
0
10
20
30
40
50
60
70
80
90
100
-500 -400 -300 -200 -100 0 100 200 300 400 500
Pulp potential (mV vs SHE)
Mineralrecoveryat1min(%)
Enargite (pH 8)
Chalcopyrite (pH 8)
0
10
20
30
40
50
60
70
80
90
100
-500 -400 -300 -200 -100 0 100 200 300 400 500
Pulp potential (mV vs SHE)
Mineralrecoveryat1min(%)
Enargite (pH 8)
Chalcopyrite (pH 8)
Senior et al J. Min Eng. Int, In press
9. Green Processing 2006: 5-6 June 9
Selective RoastingSelective Roasting
Roasting has been used to remove arsenic from ores and
concentrates
A number of treatment options have been developed and
reviewed in literature
Operating windows for selective removal of arsenic from copper
concentrates identified through thermodynamic modelling
11. Green Processing 2006: 5-6 June 11
Effect of Oxygen Supply at 700 CEffect of Oxygen Supply at 700 C
100
80
40
60
20
0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
O2 : chalcopyrite (mol:mol)
RemovalofArsenic(%)
5.3% As
0.54% As
0.055% As
700 ° C
FeAsO4
100
80
40
60
20
0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
O2 : chalcopyrite (mol:mol)
RemovalofArsenic(%)
5.3% As
0.54% As
0.055% As
700 ° C
FeAsO4
Nakazawa, Yazawa & Jorgensen Met Trans 30B, 1999
12. Green Processing 2006: 5-6 June 12
Effect of Oxygen Supply at 900 CEffect of Oxygen Supply at 900 C
100
80
40
60
20
0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
O2 : chalcopyrite (mol:mol)
RemovalofArsenic(%)
5.3% As
0.54%
0.055%
900 °C
100
80
40
60
20
0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
O2 : chalcopyrite (mol:mol)
RemovalofArsenic(%)
5.3% As
0.54%
0.055%
900 °C
Nakazawa, Yazawa & Jorgensen Met Trans 30B, 1999
13. Green Processing 2006: 5-6 June 13
Arsenic Removal from CopperArsenic Removal from Copper
Concentrate during RoastingConcentrate during Roasting
Smelter Roaster* Temp.
(°C)
Arsenic in
feed
(wt %)
Arsenic
removal
(%)
Sulphur
removal
(%)
US EPA MH 540 0.2 27 -
US EPA FB 540 to 620 0.02 15 -
El Indio MH 720 max. 6.4 >90 56
Saganoseki FB 685 to 705 5 to 6 85 to 90 60 to 70
Lepanto FB 700 1.3 82 60
Oroya MH 700 2.6 76 53
Boliden FB 700 to 720 2 92 56
*MH = multi-hearth and FB = fluidized bed
14. Green Processing 2006: 5-6 June 14
Distribution of As, Bi, Pb duringDistribution of As, Bi, Pb during
SmeltingSmelting
40 45 50 55 60
0
25
50
75
100
T=1573 K
PSO2
=0.1 atm
Iron silicate slag
bBi
Gas
Matte
40 45 50 55 60
0
25
50
75
100
T=1573 K
PSO2
=0.1 atm
Calcium ferrite slag
T=1573 K
PSO2
=0.1 atm
Calcium ferrite slag
eBi
Gas
Matte
wt% Cu in matte
40 45 50 55 60
0
25
50
75
100
T=1573 K
PSO2
=0.1 atm
Iron silicate slag
aAs
Slag
Gas
Matte
Distribution(%)
40 45 50 55 60
0
25
50
75
100
T=1573 K
PSO2
=0.1 atm
Calcium ferrite slag
d
Matte
As
Slag
Gas
Distribution(%)
wt% Cu in matte
40 45 50 55 60
0
25
50
75
100
cT=1573 K
PSO2
=0.1 atm
Iron silicate slag
Pb
Gas
Matte
40 45 50 55 60
0
20
40
60
80
100
fPb
Gas
Matte
wt% Cu in matte
Chen et al Sohn Intl Symp , 2006
15. Green Processing 2006: 5-6 June 15
Simulated FlowsheetSimulated Flowsheet
Converting
1st
& 2nd
Stages
Smelting
Fire-refining
1st
& 2nd
Stages
Copper
Conc
Slag
Slag
Matte
Blister Copper
Anode Copper
Gas
Gas
Gas
Air + Flux
Air + Flux
Air/Methane
16. Green Processing 2006: 5-6 June 16
Arsenic DistributionArsenic Distribution
-- From Concentrate to Anode CopperFrom Concentrate to Anode Copper
0
25
50
75
100
Smelting Convert 1 Convert 2 Fire-ref 1 Fire-ref 2
Processing Step
ArsenicDistribution(%)
Gas
Slag
Matte/ Copper
0.1 wt% As in Conc
Iron silicate slag
17. Green Processing 2006: 5-6 June 17
Arsenic DeportmentArsenic Deportment
- From Concentrate to Anode Copper- From Concentrate to Anode Copper
0
25
50
75
100
Smelting Convert 1 Convert 2 Fire-ref 1 Fire-ref 2
Processing Step
ArsenicDeportment(wt%)
Gas
Slag
Matte/Copper
0.1 wt % As in Conc
Iron silicate slag
18. Green Processing 2006: 5-6 June 18
Copper Production from SulfideCopper Production from Sulfide
OresOres
Ore
Tailing
Dam
Anode
Slimes
Smelting
Air, Flux, Coal Air, Flux
Acid Plant
Concentrate Matte Blister
Anode
Copperr Copper
99.99%
Anode
Slimes
Air, Natural Gas
Air, Flux
Slag
SlagSlagSlag
Acid
Dore Metal (Ag-
Au)
Tailings
Gypsum
Tailing Dam
Tailing
Dam
Flotation Smelting 2-stage
Converting
Fire-refining Electro-
refining
19. Green Processing 2006: 5-6 June 19
Safe Disposal of Toxic ElementsSafe Disposal of Toxic Elements
Production of arsenic and other toxic elements is well in excess
of market demand
Typically concentrated in form of fumes, dross, precipitates and
slags
Disposal of surplus in a safe and environmentally acceptable
manner
Thus conversion to a less hazardous form and longer term
solutions are required
conversion into calcium arsenate, ferric arsenate etc.
encapsulation in concrete or locking in silicate slags
Careful assessment of these options is required
20. Green Processing 2006: 5-6 June 20
The Early Removal OptionsThe Early Removal Options
Tailing
Dam
Flotation
Roaster
Smelter
Low As
Conc
High As
Conc
Low As
Conc
Safe Disposal
e.g mine backfill
Ore
Arsenic Fumes
21. Green Processing 2006: 5-6 June 21
ConclusionsConclusions
Increasing pressure on metal producers to reduce emissions
and manage toxic elements deportment
Challenge - orebodies with higher levels of minor elements,
which are difficult to process
Early removal option offers competitive advantage
Several options for safe disposal of low volume highly toxic
streams, which could be linked with the early removal
We believe, it is time to put current capability into practice by
examining the integrated flowsheets to deal with the
management of the minor elements in a more sustainable
way.
22. Green Processing 2006: 5-6 June 22
AcknowledgementAcknowledgement
Some of the work and findings presented were generated
through a project carried out under the auspice and
financial support of the Cooperative Research Centre for
Sustainable Resource Processing, which was established
and is supported under the Australian Government's
Cooperative Research Centres Program
Editor's Notes
Each year Australia exports ~ 3 millions of tonnes of copper, nickel, lead and zinc in form of concentrate and refined metals.
Base metal ores contain low levels of toxic/hazardous elements e.g: As, Sb, Bi, Cd, Hg, Se, Te …, Th, U.
Clean, coarsely-grained ore bodies becoming depleted
Ore bodies of future becoming more complex, finer-grained and containing higher amount of minor/toxic elements.
Worldwide industry mines and process 100s million tpa of base metal ores
Accumulated mass of minor elements in biosphere is large and could have a significant environmental impact.
Removal and safe disposal of minor elements present technical and environmental problems as well as being costly
Smelters impose treatment charges and penalty payment on minor elements in concentrates, because of difficulties in their removal and safe disposal
Governments are becoming increasingly sensitive to emissions from smelters,
Pressure is building from the community for more sustainable processing
Smelter are setting tighter penalty specifications,
With increasing demand for base metals and increasing levels of minor elements in ores, there is an imperative to develop alternative treatments that allow removal of toxic elements at the mine site before despatch of concentrate to smelters
Primarily determined by mineralogy and grain size
Occurrence - association with other elements
Distribution between phases
If minor elements are widely and uniformly dispersed in mineral phases (as in a solid solution) treatment option is limited to separation and removal in waste or residue streams produced during smelting to recover valuable components
If toxic elements are concentrated in in discrete phases, options exists for early removal by physical and chemical means.
Physical means include separation based on differences in grain size or density, flotation characteristics, while chemical means include selective roasting or leaching
Having separated and concentrated the toxic elements, consideration has to be given to their use or safe disposal.
Is a good example of impurity element found in most base metal ores and concentrates
Lowers metal quality, if not removed from product metal
Contributes to health concerns during metallurgical processing
Causes environmental concerns during disposal of tailings and wastes
High arsenic levels in an ore can make the deposit economically unviable
Blending of high and low arsenic concentrates has been practiced by industry. Can we continue this in the future? Given the depleting clean and coarse-grained ore bodies, then the answer is NO.
We will use arsenic as an example to illustrate and compare the current processing options with alternative treatment options, namely early removal and safe disposal, that could offer a number of benefits.
In copper ores arsenic occurs as
Enargite (Cu3AsS4)Tennanite (3Cu2S.As2S3)
Arsenopyrite (FeAsS)Cobaltite (CoAsS)
In nickel systems
Gersdorffite (NiAsS)Niccolite (NiAs)
Arsenopyrite (FeAsS)Cobaltite (CoAsS)
Physical separation of As bearing minerals from non-arsenic bearing minerals is difficult
As they have similar specific gravity, non-magnetic, strongly floatable with conventional collectors etc.
Second important point is that some As minerals contain high concentration of copper and nickel e.g. enargite (Cu3AsS4) has 48% Cu
Recently, CSIRO has made advances in physical separation of arsenic-containing minerals from valuable minerals by floatation.
Given that the flotation behaviour of sulphide minerals depends on the oxidation-reduction state of pulp, then one can exploit this pulp potential effects to promote separation of arsenic-bearing sulphides such as enargite from non-arsenic sulphides.
A good example of applying this to separation of Enargite from Chalcopyrite is shown in this figure, where through controlling the pulp potential (between -25 and 50 mv at a pH of 8) selective flotation and separation of enargite should be possible.
Furthermore, according to the database developed at CSIRO, other copper-iron sulphide minerlas including birnite (Cu5FeS4) should be similar to that of Chalcopyrite.
Roasting has been used to remove arsenic from ores and concentrates
Elemental arsenic and its sulfides, chlorides and oxides are volatile at roasting temperatures and a number of treatment options have been developed and reviewed in literature.
Nakazawa, Yazawa and Jorgensen applied thermodynamics to simulate the removal of arsenic from copper concentrates in presence of oxygen
More recently Jorgensen and co-workers applied roasting technique to remove arsenic from nickel concentrate
Roasting has been used to remove arsenic from ores and concentrates
Elemental arsenic and its sulfides, chlorides and oxides are volatile at roasting temperatures and a number of treatment options have been developed and reviewed in literature.
Nakazawa, Yazawa and Jorgensen applied thermodynamics to simulate the removal of arsenic from copper concentrates in presence of oxygen
This figure shows some of the results from Nakazawa et al’s work on the effects of temperature and initial arsenic content on the degree of removal via roasting the concentrate with oxygen.
It is evident that the effect of temperature becomes more pronounced for low Arsenic containing concentrate, where vapour pressure of As bearing species is too low at lower temperatures for the set oxygen supply rate.
The effect of oxygen supply is shown in this figure, where maximum arsenic removal is achieved at Oxygen to chalcopyrite ratios between 2.5 and 3.5. At higher oxygen supply rate, oxidation of concentrate to non-volatile ferric arsenate occurs and results in sharp drop in the arsenic removal.
At higher temperature of 900 C, similar behaviour was predicted, but with some sudden dip in the extent of removal caused by the formation of non-volatile Cu3As as well as As2O3.
According to these results the ratio of 2.4 moles of oxygen per mole of chalcopyrite seems to be the optimum at 900 C.
This table compares results obtained from a number laboratory and plant scale practices. These results confirm the predictions by thermodynamic modelling i.e:
Low degree of arsenic removal at temperatures below 700 C and/or low initial arsenic content
Very high degree of arsenic removal from concentrates with &gt; 1% initial arsenic and at temperatures close to 700 C.
Recent work at CSIRO has shown high degree of arsenic removal from nickel concentrates.
We may thus conclude that selective roasting can convert the high arsenic-bearing concentrates into very low arsenic concentrate for smelters.
If toxic elements are dispersed at low levels through the valuable mineral component of concentrate, their removal is accomplished during smelting, converting and refining steps.
During smelting copper concentrate is reacted with air to oxidise and remove some of the sulphur and iron from the molten matte phase
CSIRO’s MPE package covers thermodynamic behaviour of several minor elements in slags, mattes, alloys and gas phases.
In this figure the predicted behaviour of As, Bi and Pb are shown during the smelting of copper concentrate to high grade mattes.
Arsenic and antimony report predominantly to gas phase
Bismuth and lead tends to concentrate in the gas phase while Selenium and tellurium report to the matte phase
The predicted behaviour have been shown to be in close agreement with laboratory data as well as plant data.
Calculations were carried out for converting of matte produced by smelting, using a 2-stage Pierce Smith converter, followed by fire-refining of the blister copper to produce anode copper.
For each stage of the flowsheet, the distribution of minor elements between condensed and gas phases was calculated.
The results for arsenic through these thermodynamic calculations are presented in this Figure.
It is evident that in the smelting step over 70% of the input arsenic reports to the gas phase with the remainder being distributed between the matte and slag.
The conversion of matte to blister copper results in further removal of the arsenic by the gas phase, but it is predominantly dispersed in the while metal and blister copper phase.
During the fire-refining very little of the remaining arsenic reports to the gas phase.
In this figure the overall deportment of arsenic between the phases is presented, where about 70% of the input arsenic is captured by the gas phase.
About 20% of the input arsenic reports to the slag phase and only 10% finds its way to the electro-refining.
Results for bismuth and lead show that these elements mostly report to the gas phase, with the residual concentration in the metal being extremely low.
On the other hand nearly all the Se and Te reported to the fire-refined anode copper.
While 70% of input arsenic and a portion of other toxic elements report to the gas streams, effective collection and safe disposal of these toxic elements is a significant issue, particularly when dirty concentrates are being treated.
Generally a portion of arsenic and other volatile species condense in the bag-houses with small portion reporting to the acid plant.
The portion that reports to acid plant is generally converted into gypsum and stored or disposed in tailing dams.
The condense fumes, which contain arsenic and other volatile elements, are sometimes recycled through the smelter for recovery of valuable components such as copper.
The production of arsenic and other toxic elements is well in excess of market demand
Typically these elements are produced by-products of smelting operations and are concentrated in form of fumes, dross, precipitates and slags
Consideration has to be given to the disposal of surplus in a safe and environmentally acceptable manner
This requires conversion to a less hazardous form and if the volume is small storage as a temporary solution
Longer term solutions are required
Arsenic trioxide is water soluble and requires conversion to more stable compounds before disposal
A number of options have been proposed in the past. These include; conversion into calcium arsenate, ferric arsenate or scorodite, encapsulation in concrete and locking the arsenic in silicate slags.
Each option has some merits and limitations. A careful assessment of these options is required.
The treatment options for managing the minor elements are determined b y their level and mineralogy in the primary flotation concentrate.
Low levels &lt;0.5% may be acceptable to a smelter without further treatment and subsequent processing involves conventional smelting and refining
However for higher levels additional processing may be required.
For cases where the arsenic is present as discrete grains and the gangue can be rejected to produce a clean concentrate then the flowsheet shown here could be considered. Here through combination of early removal by floatation and selective roasting of high arsenic portion the feed material to the smelter will be low arsenic concentrate.
If on the other hand the arsenic minerals are not amendable to differential floatation, it would be necessary to roast all the primary concentrate in order to produce a clean concentrate.
There is increasing community and government pressure on metal producers to reduce emissions and manage toxic elements deportment in an environmentally acceptable and sustainable way.
Metal producers are facing the challenge of orebodies with higher levels of minor elements, which are difficult to process
There is now an increased focus on minor element deportment in flowsheet development for base metals ores
The early removal option offers competitive advantage in respect to minor elements dispersion and management issues, as well as maintaining overall valuable metal recovery
There are several options for safe disposal of low volume highly toxic streams which could be generated with the early removal in processing
We believe it is time to put current capability into practice by examining the integrated flowsheets that deal with the management of the minor elements in a more sustainable way. This will involve, modelling, rigorous testing at laboratory and pilot scale followed by techno-economic evaluation and life cycle assessment.
