Most evaporites are derived from bodies of Sea-water, but under special conditions, Inland lakes may also give rise to evaporite deposits, particularly in regions of low rainfall and high temperature.
Evaporite deposits are excellent indicators of paleoclimate (need a hot and arid climate for major evaporite deposits to form)
Komattite
Named after the Komati River in South Africa.
first described by Morris and Richard (twins) for ultramafic units in the Barberton Greenstone belt of South Africa.
Mostly of komatiite are Archean age
distributed in the Archaean shield areas.
Also a few are Proterozoic and Phanerozoic.
In all ages komatiites are highly magnesium.
Mostly a volcanic rock; occasionally intrusive.
Mafic rocks were identified as extrusive because of their volcanic textures and structures, and they seem to have been accepted as a normal component of Archean volcanic successions, Abitibi in Canada.
The ultramafic rocks were interpreted as intrusive which are founded as sills and dykes, Barberton in South Africa.
Spinifex texture-typical of Komatiites:
This is my presentation on the tectonic control of sediments.
It includes the effects of tectonics either direct or indirect on sediments and sedimentation.
Sedimentation along various plate boundaries.
Few examples as evidence from Pakistan (the Siwalik Group) and Argentina (Fiambala Basin)
Komattite
Named after the Komati River in South Africa.
first described by Morris and Richard (twins) for ultramafic units in the Barberton Greenstone belt of South Africa.
Mostly of komatiite are Archean age
distributed in the Archaean shield areas.
Also a few are Proterozoic and Phanerozoic.
In all ages komatiites are highly magnesium.
Mostly a volcanic rock; occasionally intrusive.
Mafic rocks were identified as extrusive because of their volcanic textures and structures, and they seem to have been accepted as a normal component of Archean volcanic successions, Abitibi in Canada.
The ultramafic rocks were interpreted as intrusive which are founded as sills and dykes, Barberton in South Africa.
Spinifex texture-typical of Komatiites:
This is my presentation on the tectonic control of sediments.
It includes the effects of tectonics either direct or indirect on sediments and sedimentation.
Sedimentation along various plate boundaries.
Few examples as evidence from Pakistan (the Siwalik Group) and Argentina (Fiambala Basin)
The name ophiolite derived from Greek root which means
Ophio : snake or serpent Litho : Stone
The green colour, structure and texture of sheared ultramafic rocks is similar to some serpents
Economically :
Massive Sulphide
It founded within pillow lava most of massive Sulphide associated in ophiolites have well developed Gossans (bright colored iron oxide, hydroxides, and sulfides) which is very rich in gold.
Chromite
Stratiform (be tabular or pencil shape) or podiform (irregular shape) within ultra-mafic rocks
These deposits are developed on serpentinite peridotite
Laterites (nickel and iron)
Asbestos
Talc
Magenesite
ophiolite sequence :
Sediments
Pillow Lavas
Dykes
Gabbros
Layered Gabbro
Layered Peridotite
Upper mantle
SUPERGENE ENRICHMENT; Definition; Zones; Morphology of Zoning; Oxidized zone ; Supergene zone ; Gossans and Cappings; Chemical Changes Involved; Electrowinning; Formation of Copper Oxides
How can minerals deposits be formed; GEOLOGICAL PROCESSES; Ore Fluids; Ore Forming Processes; Concentrating Processes; Magmatic mineral deposits; Residual mineral deposits ; Placer deposits; Sedimentary mineral deposits; Metamorhogenic mineral deposits; Hydrothermal mineral deposits ; Magmatic Deposits
Cumulate deposits: fractional crystallization processes can concentrate metals (Cr, Fe, PGE, Pt, Ni, Ti, Diamond ))
Pegmatites : late staged crystallization forms pegmatites and many residual elements are concentrated (Li, Ce, Be, Sn, U, Rare Earths (REE), Feldspar, Mica, Gems).
magmatic deposits; Mode of Formation of Magmatic Ores Deposits; Mode of Formation of Orthomagmatic Ores ; Fractional Crystallization (or Crystal fractionation ); Magmatic (or Liquid ) Immiscibility; Simple crystallization without concentration (Dissemination); Segregation of early formed crystals; (Layer Types); Injection of material concentrated elsewhere by differentiation Residual liquid segregation; Residual liquid injection; Immiscible liquid segregation; Immiscible-liquid-injection; Early magmatic deposit; Late magmatic deposit; Types of Magmatic Ore Deposits:Chromite; Fe-Ti (± V) oxides; Ni – Cu – Fe (± Pt) sulfides; Platinum Group Elements (PGEs); REE, and Zr in Carbonatites; Diamond in kimberlites.
Hi I'm Misson Choudhury , A Post Graduate student, Graduated from Utkal university and Now pursuing my m.sc in applied geology at Bangalore university, Bangalore, i love geological mapping,drawing,hill climbing and tracking..
Phosphorite deposits, Types of Phosphorite deposits , Igneous Phosphate Deposits, Biogenic (or Guano Bird ; or Island) Deposits, Marine Sedimentary Phosphate Deposits, Classification of Phosphatic Sedimentary Marine Rocks, Depositional Environments, Types of Sedimentary Phosphorite Deposition, Nature and Occurrence, Mineralogy and Mineral composition of phosphorite deposit, Origin of Phosphorite, World Phosphate Rock Reserves and Resources, Global Phosphate Rock Production, Use of Phosphate
What is an ore?, Ore deposit environments, Formation of Mineral Deposits, Endogenous (Internal) processes, Exogenous (Surficial) processes, Types of Sedimentary Rocks, Mineral Deposits Associated with Sedimentary Process, physical processes of ore deposit formation in the surficial realm, Erosion, weathering , transportation, sorting, Precipitation, Depositional Environments, Deposits formed by Weathering, Deposits formed by Sediment, Resources from the Sedimentary Environments
The name ophiolite derived from Greek root which means
Ophio : snake or serpent Litho : Stone
The green colour, structure and texture of sheared ultramafic rocks is similar to some serpents
Economically :
Massive Sulphide
It founded within pillow lava most of massive Sulphide associated in ophiolites have well developed Gossans (bright colored iron oxide, hydroxides, and sulfides) which is very rich in gold.
Chromite
Stratiform (be tabular or pencil shape) or podiform (irregular shape) within ultra-mafic rocks
These deposits are developed on serpentinite peridotite
Laterites (nickel and iron)
Asbestos
Talc
Magenesite
ophiolite sequence :
Sediments
Pillow Lavas
Dykes
Gabbros
Layered Gabbro
Layered Peridotite
Upper mantle
SUPERGENE ENRICHMENT; Definition; Zones; Morphology of Zoning; Oxidized zone ; Supergene zone ; Gossans and Cappings; Chemical Changes Involved; Electrowinning; Formation of Copper Oxides
How can minerals deposits be formed; GEOLOGICAL PROCESSES; Ore Fluids; Ore Forming Processes; Concentrating Processes; Magmatic mineral deposits; Residual mineral deposits ; Placer deposits; Sedimentary mineral deposits; Metamorhogenic mineral deposits; Hydrothermal mineral deposits ; Magmatic Deposits
Cumulate deposits: fractional crystallization processes can concentrate metals (Cr, Fe, PGE, Pt, Ni, Ti, Diamond ))
Pegmatites : late staged crystallization forms pegmatites and many residual elements are concentrated (Li, Ce, Be, Sn, U, Rare Earths (REE), Feldspar, Mica, Gems).
magmatic deposits; Mode of Formation of Magmatic Ores Deposits; Mode of Formation of Orthomagmatic Ores ; Fractional Crystallization (or Crystal fractionation ); Magmatic (or Liquid ) Immiscibility; Simple crystallization without concentration (Dissemination); Segregation of early formed crystals; (Layer Types); Injection of material concentrated elsewhere by differentiation Residual liquid segregation; Residual liquid injection; Immiscible liquid segregation; Immiscible-liquid-injection; Early magmatic deposit; Late magmatic deposit; Types of Magmatic Ore Deposits:Chromite; Fe-Ti (± V) oxides; Ni – Cu – Fe (± Pt) sulfides; Platinum Group Elements (PGEs); REE, and Zr in Carbonatites; Diamond in kimberlites.
Hi I'm Misson Choudhury , A Post Graduate student, Graduated from Utkal university and Now pursuing my m.sc in applied geology at Bangalore university, Bangalore, i love geological mapping,drawing,hill climbing and tracking..
Phosphorite deposits, Types of Phosphorite deposits , Igneous Phosphate Deposits, Biogenic (or Guano Bird ; or Island) Deposits, Marine Sedimentary Phosphate Deposits, Classification of Phosphatic Sedimentary Marine Rocks, Depositional Environments, Types of Sedimentary Phosphorite Deposition, Nature and Occurrence, Mineralogy and Mineral composition of phosphorite deposit, Origin of Phosphorite, World Phosphate Rock Reserves and Resources, Global Phosphate Rock Production, Use of Phosphate
What is an ore?, Ore deposit environments, Formation of Mineral Deposits, Endogenous (Internal) processes, Exogenous (Surficial) processes, Types of Sedimentary Rocks, Mineral Deposits Associated with Sedimentary Process, physical processes of ore deposit formation in the surficial realm, Erosion, weathering , transportation, sorting, Precipitation, Depositional Environments, Deposits formed by Weathering, Deposits formed by Sediment, Resources from the Sedimentary Environments
Solution Mining; Technology of the Salt Production; Rock salt (NaCl); Sylvinite; Solution mining of carnallitite with; two wells; selective dissolution; hot leaching; Methods to control the size of the caverns; INTRODUCTION; TECHNOLOGY OF SOLUTION MINING; FRASCH PROCESS-SULFUR PRODUCTION; TECHNOLOGY OF THE SALT PRODUCTION; What is Rock salt ?; Evaporite deposits ; Rock salt; Sylvinite; Carnallite; HEAP LEACHING; Heap leach production model; Important parameters during metallurgical testing; Staged Approach to Heap Leach Testwork and Design; Uranium Heap Leaching; Uranium Ore Minerals; Basic Geochemistry of Uranium Minerals; Copper Heap Leaching; Layout of copper bio-heap pilot plant; Laterite heap leaching; Nickel Laterite Deposits; Proposed counter-current heap leach arrangement; Neutralizing potential of laterites in 6 meter column; Advantages and Problems of Solution Mining
Potash is a potassium-rich salt that is mined from underground deposits formed from evaporated sea beds millions of years ago. Potassium is an essential element for all plant, animal and human life. The term "potash" refers to a group of potassium (K) bearing minerals and chemicals.
MINES WASTES; WASTE-ROCK DISPOSAL (ROCK DUMPS); WASTEWATER; TAILINGS & TAILINGS COMPOSITION; Tailings Solids; Tailings liquid; Tailings waters; Sulphidic mine wastes; Acid Mine Waters; TAILINGS DISPOSAL METHODS; Dynamic Simulation of a Tailing Storage Facility (TSF); Tailings Dam Styles (or Configurations); Fundamental Constructed Elements of a Tailings Dam; Water Balance of a Tailings Dams; Disposal Methods; THICKENED DISCHARGE AND PASTE DISPOSAL; IN-PITWASTE DISPOSAL; SEEPAGE FLOW TO SURFACE WATER AND GROUNDWATER; RIVERINE TAILINGS DISPOSAL; SUBMARINE TAILINGS DISPOSAL; Alternative Location To Tailing
Chemical Oceanography is fundamentally interdisciplinary. The chemistry of the ocean is closely tied to ocean circulation, climate, the plants and animals that live in the ocean, and the exchange of material with the atmosphere, cryosphere, continents, and mantle
This presentation was prepared for the Final Presentation in the Sea Floor course. It gives advanced information for understanding deep-sea environments with chemical oceanography and geochemistry insights.
The objectives of this course in iron ore Resources and iron industry are:
i) acquainting students (majors and non-majors) with the basic tools necessary for studying iron ore deposits and processes,
ii) different processes for phosphorus removal from iron ore
iii) beneficiation processes of iron ore deposits.
iv) different processes and techniques that used to enrichment low-grade iron ore resources
v) understanding the different ironwork processes and technology,
vi) understanding the different types of iron ore products,
vii) prominent routes for steelmaking
viii) understanding the relationship between the distribution of iron ore and scrap, as well as steelmarkets,
ix) steel industry in Egypt , and
x) gaining some knowledge of the global iron ore as well as environmental problems associated with the extraction and utilization of iron ore resources.
There are plenty of hard-to-beneficiate iron ores and high-grade tailings in India and all over the world; As the volume of high-grade iron ores declines.
Minerals phase transformation by hydrogen reduction (MPTH) can efficiently revitalize hard-to-beneficiate iron ore resources and tailings, turning the waste into profitable products. It may also improve the concentrate quality comparing to that from the previous method. From the economic and environmental aspects, MPTH is the most effective method to recover iron oxides.
The clean minerals phase transformation by hydrogen reduction (MPTH) was proposed.
Industrial utilization of limonite/goethite, limonite-hematite, sulfur-bearing refractory iron ore was achieved, where Sulfur-bearing minerals decomposed or formed sulfate after oxidation roasting.
Sulfur content of iron ore concentrate was significantly reduced to 0.038 %.
Improving utilization efficiency of refractory iron ore resources is a common theme for the sustainable development of the world’s steel and iron industry.
Magnetization Roasting is considered as an effective and typical method for the beneficiation of refractory iron ores.
After magnetization roasting, the weakly magnetic iron minerals, including hematite, limonite and siderite, are selectively reduced or oxidized to ferromagnetic magnetite, which is relatively easier to enrich by Magnetic Separation after liberation pretreatments.
The Primary Magnetization Roasting Methods include: Shaft Furnace Roasting, Rotary Kiln Roasting, Fluidized Bed Roasting, and Microwave assisted roasting. The developments in magnetization roasting of difficult to treat iron ores, including: Shaft Furnace Roasting, Rotary Kiln Roasting, Fluidized Bed Roasting, and Microwave Assisted Roasting in the Past Decade.
Shaft Furnace Roasting is gradually eliminated due to its high energy consumption and low industrial processing capacity, and the primary problem for rotary kiln roasting is the kiln coating which affects the yield of iron resource and its industrial application.
Fluidized Bed Roasting and Microwave assisted roasting are considered as the most effective and promising methods.
Suspension (Fluidized) Magnetization Roasting is recognized as the most effective and promising technology due to its high reaction efficiency, low energy consumption and large processing capacity. Moreover, an industrial production line with a throughput of 1.65 million t/a for beneficiation of a specularite ore has been built.
Microwave Assisted Roasting is a potential alternative technology for magnetizing iron ores. However, it is currently limited to laboratory research and has no industrial application. Forwarding microwave assisted magnetization roasting methods into industrial applications needs long way and time to achieve.
Furthermore, using biomass, H2 or siderite as a reducing agent in the magnetic reduction roasting of iron ores is a beneficial way to reduce carbon emissions, which can be called clean and green magnetization roasting technology.
In the future, technical research on clean and green magnetization roasting should be strengthened. Maybe microwave magnetization roasting using biomass/H2/siderite as reductant can be further studied for a more effective and greener magnetization of iron ores.
WORLD RESOURCES IRON DEPOSITS
Iron Ore Pellets Market Industry Trends
Scope and Market Size
Market Analysis and Insights
DRI Production in Plants Using Merchant Iron Ore
Outlook for DR grade pellet supply‐demand out to 2030
DRI and the pathway to carbon‐neutral steelmaking
Supply‐side challenges for the steel & iron ore industries
scrap is the main raw material, is growing in the structure of global steelmaking capacities; SCARP/ RECYCLING IRON ; EAF steel production method in the world; Scrap for Stock; A Global Scrap Shortage;Availability of Ferrous Scrap Resources; EGYPT IRON SCRAP IMPORTS.
The iron ore production has significantly expanded in recent years, owing to increasing steel demands in developing countries.
However, the content of iron in ore deposits has deteriorated and low-grade iron ore has been processed.
The fine ores resulting from the concentration process must be agglomerated for use in iron and steelmaking.
Bentonite is the most used binder due to favorable mechanical and metallurgical pellet properties, but it contains impurities especially silica and alumina.
Better quality wet, dry, preheated, and fired pellets can be produced with combined binders, such as organic and inorganic salts, when compared with bentonite-bonded pellets.
While organic binders provide sufficient wet and dry pellet strengths, inorganic salts provide the required preheated and fired pellet strengths.
The industrial development program of any country, by and large, is based on its natural resources.
Currently the majority of the world’s steel is produced through either one of the two main routes: i) the integrated Blast Furnace – Basic Oxygen Furnace (BF – BOF) route or ii) the Direct Reduced Iron - Electric Arc Furnace (DRI - EAF) route.
Depleting resources of coking coal, the world over, is posing a threat to the conventional (Blast Furnace [Bf]–Basic Oxygen Furnace [BOF]) route of iron and steelmaking.
During the last four decades, a new route of ironmaking has rapidly developed for Direct Reduction (DR) of iron ore to metallic iron by using noncoking coal/natural gas.
This product is known as Direct Reduced Iron (DRI) or Sponge Iron.
Processes that produce iron by reduction of iron ore (in solid state) below the melting point are generally classified as DR processes.
Based on the types of reductant used, DR processes can be broadly classified into two groups: (1) coal-based DR process and (2) gas-based DR process.
Details of DR processes, reoxidation, storage, transportation, and application of DRI are discussed in this presentation.
This presentation reviews the different DR processes used to produce Direct Reduced Iron (DRI), providing an analysis on the quality requirements of iron-bearing ores for use in these processes. The presentation also discusses the environmental sustainability of such processes. DR processes reduce iron ore in its solid state by the use of either natural gas or coal as reducing agents, and they have a comparative advantage of low capital costs, low emissions and production flexibility over the BF process.
Currently the majority of the world’s steel is produced through either one of the two main routes: i) the integrated Blast Furnace – Basic Oxygen Furnace (BF – BOF) route or ii) the Direct Reduced Iron - Electric Arc Furnace (DRI - EAF) route.
In the former, the blast furnace uses iron ore, scrap metal, coke and pulverized coal as raw materials to produce hot metal for conversion in the BOF. Although it is still the prevalent process, blast furnace hot metal production has declined over the years due to diminishing quality of metallurgical coke, low supply of scrap metal and environmental problems associated with the process. These factors have contributed to the development of alternative technologies of ironmaking, of which Direct Reduction (DR) processes are expected to emerge as preferred alternatives in the future.
This presentation reviews the different DR processes used to produce Direct Reduced Iron (DRI), providing an analysis on the quality requirements of iron-bearing ores for use in these processes. The presentation also discusses the environmental sustainability of such processes. DR processes reduce iron ore in its solid state by the use of either natural gas or coal as reducing agents, and they have a comparative advantage of low capital costs, low emissions and production flexibility over the BF process.
Ironmaking represents the first step in steelmaking.
The iron and steel industry is the most energy-intensive and capital-intensive manufacturing sector in the world (Strezov, 2006).
Steelmaking processes depend on different forms of iron as primary feed material. Traditionally, the main sources of iron for making steel were Blast Furnace hot metal and recycled steel in the form of scrap.
The Blast Furnace (BF) has remained the workhorse of worldwide virgin iron production (i.e., hot metal) for more than 200 years. Over the years, BFs have evolved into highly efficient chemical reactors, capable of providing stable operation with a wide range of feed materials.
However, operation of modern efficient BFs normally involves sintering and coke making and their associated environmental problems.
More than 90% of iron is currently produced via the BF process, while the rest is coming from Direct Reduction (DR) processes, Mini Blast Furnaces (MBFs), Corex, Finex, Ausmelt, etc. Additionally, the severe shortage of good-quality metallurgical coal has remained an additional constraint all over the world. In view of this, there is an increasing awareness that the BF route needs to be supplemented with alternative ironmaking processes that are more environment friendly and less dependent on metallurgical coal.
Because of the rapid depletion of easily processed iron ores, the utilization of refractory ores has attracted increasing attention .
There several billion tonnes iron deposits, and most are refractory ores, which are difficult to process by conventional methods because of the low iron grade, fine grain size and complex mineralogy.
The beneficiation of low-grade iron ores to meet the growing demand for iron and steel is an important research topic.
At present, magnetization roasting followed by magnetic separation is one of the most effective technologies for the beneficiation of refractory iron ores.
However, certain ores do not qualify to be treated in physical separation processes, and hence, alternative strategies are being looked into for upgrading their iron content.
Reduction roasting has many advantages over the physical beneficiation process, such as enhanced iron recovery and processing of complex and poorly liberated iron ores.
The objective of this presentation is to compile and amalgamate the crucial information regarding the beneficiation of low-grade iron ores using carbothermic reduction followed by magnetic separation, which is a promising technique to treat iron ores with complex mineralogy and liberation issues.
Reduction roasting studies done for different types low-grade iron ores including oolitic iron ores, banded iron ores, iron ore slimes and tailings, and industrial wastes have been discussed.
Reduction roasting followed by magnetic separation is a promising method to recover the iron values from low-grade iron ores.
The process involves the reduction of the goethite and hematite phases to magnetite, which can subsequently be recovered using a low-intensity magnetic separation unit.
The large-scale technological advancements in reduction roasting and the possibilities of the application of alternative reductants as substitutes for coal have also been highlighted.
This presentation aims at insight light on the occurrence of phosphorus in iron ores from the mines around the world.
The presentation extends to the phosphorus removal processes of this mineral to meet the specifications of the steel industry.
Phosphorus is a contaminant that can be hard to remove, especially when one does not know its mode of occurrence in the ores.
Phosphorus can be removed from iron ore by very different routes of treatment. The genesis of the reserve, the mineralogy, the cost and sustainability define the technology to be applied.
The presentations surveyed cite removal by physical processes (flotation and selective agglomeration), chemical (leaching), thermal and bioleaching processes.
Removal results of above 90% and less than 0.05% residual phosphorus are noticed, which is the maximum value required in most of the products generated in the processing of iron ore.
Chinese studies show that the direct reduction roasting of high phosphorus oolitic hematite followed by magnetic separation is reality technical solutions to improve the recovery of metallic iron and dephosphorization rate.
For ores with widespread phosphorus in the iron matrix and low release, thermal or mixed processes are closer to reality technical solutions. Due to their higher operating costs, it will be necessary to rethink the processes of sintering and pelletizing, such that these operations also become phosphorus removal steps.
With the exhaustive processing of the known reserves of hematite from Iron Ore Quadrangle (Minas Gerais-Brazil), there will be no shortage of granules in the not too distant future. THEREFORE, THERE IS AN EXPECTATION THAT THE ORE MINED WILL HAVE HIGHER LEVELS OF PHOSPHORUS.
Overview of IRON TYPES: Pig Iron, Direct Reduced Iron (DRI), Hot Briquetted Iron (HBI), Cold Briquetted Iron (CBI) and Cold Briquetted Iron and Carbon (CBIC) Specifications .
Comparison of Pig Iron and DRI
Properties; Manufacturing Process; Uses; Largest producers and markets
Iron ore mining plays a critical role in supplying the raw material necessary for steel production, supporting various industries and economic development worldwide.
From the extraction of iron ore to its processing and eventual export, each stage of the mining process requires careful planning, technological advancements, and environmental considerations.
By adopting sustainable mining practices and mitigating environmental impacts, the future of iron ore mining can be aligned with the principles of responsible resource utilization and environmental stewardship
The Egyptian steel sector is the second largest steel market in the Middle East and North Africa region in terms of production and third largest in terms of consumption.
Egypt was the third-ranked producer of Direct-Reduced Iron (DRI) in the Middle east and North Africa region after Iran and Saudi Arabia and accounted for 5.4% of the world’s total output
The Egyptian steel industry represents one of the cornerstones of Egypt’s economic growth and development, due to its linkages to almost all other industries that stimulate economic expansion, such as construction, housing, infrastructure, consumer goods and automotive. All these industries rely heavily on steel industry and so, the importance and development of the steel sector is significant for the progress of the Egyptian economy in general.
The Egyptian market has many companies that produce different steel products.
Geological consultant, working in a range of roles from project development/feasibility study programs and advanced exploration roles. Contracts in a variety of global locations including Egypt, Saudi Arab, and the Middle East. Commodities including Gold, base metal sulfide, Gossan/Supergene, heavy mineral sands, clay/kaolin, Silica Sand, and iron ore.
Exploration in Deep Weathering Profiles, Supergene, R-mode factor analysis; Multi-element association geochemistry; Assessment of Au-Zn potentiality in Gossan; Rodruin-Egypt
Mineral Processing: Crusher and Crushing; Secondary and Tertiary Crushing Circuits; Types of Crusher; Types of Crushing; Types of Jaw Crushers; Impact Crusher; Types of Cone Crushers; Ball Mill; BEST STONE MANUFACTURERS; Local Quality and High quality ; International and Country/Hand made
Classification Equipment
Introduction; Chemical composition of garnet; Structure; Classification; Physical properties; Optical properties; Occurrences; Gem variety; and Uses
Garnet group of minerals is one of the important group of minerals.
Since they are found in wide variety of colours, they are also used as gemstones.
Garnet group of minerals are also abrasives and thus have various industrial applications.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Normal Labour/ Stages of Labour/ Mechanism of LabourWasim Ak
Normal labor is also termed spontaneous labor, defined as the natural physiological process through which the fetus, placenta, and membranes are expelled from the uterus through the birth canal at term (37 to 42 weeks
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
1. Evaporite Deposits
A short series of lectures prepared for the
third level of Geology, Tanta University
by
Hassan Z. Harraz
hharraz2006@yahoo.com
@Hassan Z. Harraz
Evaporite Deposits
3. DEFINATION
Evaporite mineral:
is a mineral sediment (i.e. chemical sediment)
that result originally precipitated from saline
(brine) solutions concentrated and crystallization
by solar evaporation from an aqueous solution.
Considered as Inorganic/Chemical
Sedimentary Rock types:
“Chemical”: derived from the precipitation of
dissolved minerals in water.
“Inorganic”: minerals precipitate because of
evaporation and/or chemical activity.
@Hassan Z. Harraz
Evaporite Deposits
3
4. Evaporite (or Salt) deposits
@Hassan Z. Harraz
Evaporite Deposits
that are composed of minerals that originally precipitated from saline (brine)
solutions concentrated by solar evaporation.
Most evaporites are derived from bodies of Sea-water, but under special
conditions, Inland lakes may also give rise to evaporite deposits, particularly in
regions of low rainfall and high temperature.
Evaporite deposits are excellent indicators of paleoclimate (need a hot and
arid climate for major evaporite deposits to form)
The original character of most evaporite deposits has been destroyed by
replacement through circulating fluids through geologic time
Evaporite deposits are known from all the continents,
Ages: ranging from Precambrian to Recent
Precambrian evaporite deposits are scarces, either because:
they were not deposits
they have been dissolved away during diagenesis through geologic time.
The greatest evaporite deposits are formed during Permian and Miocene
periods.
4
5. Minerals precipitated from “super-saturated” saline water in enclosed
basin environments under dry arid conditions with high evaporation
rates (e.g., playa lakes).
@Hassan Z. Harraz
Evaporite Deposits
5
6. Deposition of minerals by evaporation is dependent on factors:
1) Solubility contents,
2) Temperature,
3) Pressure,
4) Depositional environment, and
5) Seasonal and climatic changes .
PROCESS OF MINERAL FORMATION BY EVAPORATION
Requirements
Arid Environment, High
Temperature
Low Humidity
little replenishment from open
ocean, or streams
Rates of Evaporite Deposition
Rates of evaporite deposition are
FAST (compared to other sediments)
Subaqueous evaporites may be
deposited at rates exceeding 10
cm/yr!! …(Compare this to
mm/1000 yr for most sediments).
@Hassan Z. Harraz
Evaporite Deposits
6
7. 1) Chemistry of Seawater
Dissolved Species - Seawater
About 3.45% of seawater consists of dissolved
salts of which 99.7% by weight is made up of
only seven, ions that are as listed below :-
Most common ions: Cl-, Na+, Mg 2+, SO4
2-, Ca2+,
K+...
Trace components: Br, F, B, Sr
85.65 % Na2+ and Cl- ions
NaCl is most abundant because of
composition of seawater:
remaining solutes 14.35%
Na+ 30.61 Cl- 55.04
Mg2+ 3.69 SO4
2- 7.68
Ca2+ 1.16 HCO3- 0.41
K+ 1.10
CHEMISTRY OF EVAPORITES
@Hassan Z. Harraz
Evaporite Deposits
7
8. In terms of volumes of precipitated salts, experiments like that show that
if a column of sea water 1000 m (1 km) thick is evaporated to dryness,
the precipitated salt (evaporite) deposits would be about 17 m thick.
1000 m (1 km) of seawater will
produce 17 m of evaporites:
0.1 m would be CaCO3
0.6 m would be gypsum
(CaSO4.2H2O),
13.3 m would be halite (NaCl), and
the rest, 3.0 m, would be mainly
salts of potassium and magnesium
(KCl, KMgCl).
Volumes of precipitated salts
Note:
ppt. sequence controlled by
solubility – least soluble first:
least soluble
High soluble
@Hassan Z. Harraz
Evaporite Deposits
8
9. Extracted and produced by
i) Surface Mining
ii) Underground Mining
iii) Solution mining
1) Burried Evaporite deposits :
Natural
Ancient Evaporite deposits
Evaporite deposits that formed during
various warming Seasonal and
climatic change periods of geologic
times.
Like: Shallow basin with high rate of
evaporation – Gulf of Mexico, Persian
Gulf, Ancient Mediterranean Sea, Red
Sea
2) Brine Evaporite deposits:
Natural and synthetic
Evaporite deposits that formed today
from evaporation:
Ocean and Sea water
Saline Lakes water
Inland Lakes water
Extracted and produced by
Solar evaporation in:
Pond
Marsh
Evaporite Deposits
Playa lake basins
(are formed between
mountain ranges, collected)
9@Hassan Z. Harraz
Evaporite Deposits
10. ENVIRONMENTS FOR EVAPORITE PRECIPITATION
@Hassan Z. Harraz
Evaporite Deposits
Brine evaporite deposits
Found in both Marine and Continental environments
Environments
Marine:
Coastal zone
Mud flats –
Sabkhas
Salt pans
Barried basins
Continental:
Salt/Saline lakes
Springs
Groundwater
There are two types of evaporate deposits:
1) Marine evaporites: which can also be described as ocean or sea water
deposits (solutions derived from normal sea water by evaporation are said to
be hypersaline), and
2) Continental evaporites: which are found in standing bodies of water such
as Inland lakes; also groundwater.
10
11. i) Marine Evaporite Deposits
@Hassan Z. Harraz
Evaporite Deposits
11
Coastal Salt Pans
15. Salt deposits were formed during the “Messinian Salinity Crisis”, a geological event during
which the Mediterranean Sea was cut off from the Atlantic Ocean and dried up (or
mostly dried up), creating massive deposits of previously dissolved salts.
This occurred at the end of the Messinian age ( from 5.96 to 5.33 Ma ago ) of the
Miocene epoch, ending when the Atlantic again flowed into the basin
15@Hassan Z. Harraz
Evaporite Deposits
16. Volume of
water
remaining
Evaporite Precipitated
50%
At this point, minor carbonates
(CaCO3 and MgCO3 ) arebegin to
form.
A little iron oxide (Siderite) and some
aragonite are precipitated.
Minor quantities of carbonate
minerals (Calcite and dolomite) form.
a) Calcite(CaCO3):
Precipitates if < 50% of seawater is removed.
Only accounts for a small % of the total solids
20%
Gypsum precipitates:
Gypsum (<42°C) or Anhydrite (>42°C).
b) Gypsum:
Precipitates if 80-90% of seawater has been removed
Solution is denser
10% Rock salt (halite) precipitates
c) Halite:
Precipitates if 86-94% of original seawater has been
removed
Brine (solution) is very dense
The deposition of salt beds provides the source for about
three-fourths of all salt used.
5%
Mg & K salts precipitate
Precipitation of various
magnesium sulfates [Kieserite
(MgSO4) and chlorides(MgCl2),
and finally to NaBr and KCl.
Potassium and Magnesium salts
(Kainite (KMg(SO4)Cl * 3H2O),
Carnallite (KMgCl3*6H2O),
Sylvite(KCl))
d) Potassic salts:
Precipitate if > 94 % of original seawater has been
removed
So: ionic strength (potential) of evaporating seawater has
a strong control over minerals that form.
After the deposition of common salt, chlorides and sulfates of
magnesium and potassium are the other chief salts deposited.
The potassium minerals result from evaporation carried
almost to completion and, therefore, only rarely are they
deposited.
2) Evaporation Sequence of Seawater
IncreasingEvaporationRates
The first phase
Decreasingorderofsolubility
@Hassan Z. Harraz
Evaporite Deposits
16
20. Rock salt crust mined from the lake bed
@Hassan Z. Harraz
Evaporite Deposits
20
21. ii) Continental and Inland lakes Evaporite Deposits
Examples of modern continental depositional environments include the Great Salt Lake in
Utah and the Dead Sea, which lies between Jordan and Israel.
These deposits also may contain important minerals that help in today's economy.
Continental evaporite deposits often help to paint a picture into past Earth climates:
Some particular deposits even show important tectonic and climatic changes.
Primary examples of this are called “Saline lake deposits".
@Hassan Z. Harraz
Evaporite Deposits
21
Saline Inland lakes:
Salt lakes
Alkali (or Soda) Lakes
Playa lakes; which are lakes that appear
only during certain seasons,
Perennial lakes: , which are lakes
that are there year-round
Bitter (or Sulfate) Lakes
Potash Lakes
Borate Lakes
Groundwater
Hot Springs
23. Order of precipitation of common compounds in Continental waters
(saline lakes) and Inland Brine Lakes evaporation:
1) CaCO3 and MgCO3 are the 1st to precipitate
2) CaSO4 precipitates …. All calcium are precipitated ( Leaving mostly Na
and Mg cations)
3) NaCO3 are precipitated next as:
3.1) Borax (Na2B4O7·10H2O or Na2[B4O5(OH)4]·8H2O)
3.2) Borates
3.3) Nitrates
3.4) Natron (Na2CO2.10H2O)
3.5) Trona (NaHCO3.Na2CO3.2H2O)
4) NaSO4 are precipitated
5) MgSO4 and Epsomite/ Epsom salts (MgSO4.7H2O) precipitated ….. left
NaCl
6) NaCl saltern is left. These are fairly common (Great Salt Lake)
7) MgCl2 and CaCl2 lakes are precipitated
Precipitationsequence
EVAPORATION SEQUENCE OF CONTINENTAL WATERS (Saline Lakes)
@Hassan Z. Harraz
Evaporite Deposits
23
24. Figure 5.25 (a) Schematic cross section showing the important features necessary for the formation of large marine
evaporite sequences. (b) Paragenetic sequence for an evaporite assemblage from typical sea water containing the
ingredients shown in the left hand column. The amount of sea water (per 1000 liter volume) that has to evaporate in order
to consecutively precipitate the observed sequence of mineral salts is shown by the curve adjacent to the paragenetic
sequence (diagrams modified after Guilbert and Park, 1986).
24
@Hassan Z. Harraz
Evaporite Deposits
25. Kind of Inland Lakes
1) Saline Lakes:
i) Salt Lakes: rich in sodium chloride (NaCl)
ii) Alkali (or Soda) Lakes: rich in sodium carbonate (Na2CO3)
Soda lakes have enormous phytoplankton populations not
so with other sodium rich lakes.
iii) Perennial lakes, which are lakes that are there year-round; or
iv) Playa lakes, which are lakes that appear only during certain
seasons.
2) Bitter (or Sulfate) Lakes: rich in sodium sulfate (Na2SO4)
3) Potash Lakes
4) Borate Lakes
DEPOSITION FROM INLAND LAKES
@Hassan Z. Harraz
Evaporite Deposits
25
26. Playa lake basins
@Hassan Z. Harraz
Evaporite Deposits
are formed between mountain ranges,
are lakes that appear only during certain season,
Called Salt Playas,
on salt Playas, desert winds distribute sands and silt, upon which later salts may be
deposited during subsequent lake periods.
This also gives alternations of salines with sand, clay and minor calcium
carbonate.
26
27. 1) Deposition from Salt Lakes
The deposits formed from the evaporation of salt lakes are similar to
those obtained from ocean water.
The relatively small size of lakes, however, makes them more
responsive to climate changes, with the result that they exhibit
greater fluctuations of deposition.
Evaporites formed during periods of desiccation may be re-dissolved
during subsequent periods of scansion.
Moreover, lakes constantly receive new supplies of fresh water, salts,
and also sediments.
The resulting saline deposits, therefore, are generally thin-bedded
alternations of impure salts and clays.
Also, on salt Playas, desert winds distribute sands and silt, upon
which later salts may be deposited during subsequent lake periods.
This also gives alternations of salines with sand, clay and minor
calcium carbonate.
@Hassan Z. Harraz
27
29. 2) Deposition from Alkali (or Soda) Lakes
Alkali (or Soda) lakes is lake rich in sodium compounds.
In alkali or soda lakes sodium carbonate predominates, potassium
carbonate may be abundant, and common salt is always present.
Source materials: Most of the sodium carbonate has been derived directly
by decomposition of volcanic rocks, but some is also formed by slow and
complex chemical reactions with other sodium and calcium salts; it may
be formed also by the action of algae on sodium sulfate.
The potassium carbonate is considered to be the indirect product of the
work of organisms.
Example: Owens and Mono Lakes in California, the Soda Lakes of Nevada,
and the Natron Lakes of Egypt.
The Natron Lakes of Egypt are alternately wet and dry, and evaporation
leaves a layer of natron and salt, bordered by sodium carbonate.
Note:
In arid regions- precipitates of carbonate combined with
sodium are found commonly called natron and trona
@Hassan Z. Harraz
Evaporite Deposits
29
30. 3) Deposition from Bitter (or Sulfate ) Lakes
Bitternresults when water evaporates and most salts have
crystalized and precipitated The liquid that remains is called
Bittern
In bitter lakes, contains sodium sulfate predominates,
bromides and magnesium salts…. but carbonate and chloride are
present.
Source materials: The sulfate may be derived from the
decomposition of rocks that contain sulfates, or from the
leaching of buried beds of sulfates.
Such lakes are common in the Arid Regions of America and
Asia.
Examples are Verde Valley Lake in Arizona; Soda and
Searles Lakes in California; and numerous lakes in New
Mexico; Lakes Altai and Domoshakovo in Russia.
@Hassan Z. Harraz
Evaporite Deposits
30
31. 4) Deposition from Potash Lakes
Potassium
4th ranking cation
High potassium levels are lethal to many aquatic
animals
Source of potassium
The potash is believed to have come from the
surrounding country that formerly was burred
over by the Indians, releasing plant ashes.
Potash potassium carbonate (K2CO3)
Thought to be ashes of ancient fires
@Hassan Z. Harraz
Evaporite Deposits
31
32. 1.3) Potash Deposition
After the deposition of common salt, chlorides and sulfates of magnesium and
potassium are the other chief salts deposited. The potassium minerals result from
evaporation carried almost to completion and, therefore, only rarely are they
deposited.
The famous Stassfurt deposits of Germany represent the only complete sequence of
deposition of oceanic salts.
Economic sources …
Sedimentary salt beds remaining from ancient inland seas (evaporite deposits)
Salt lakes and natural brines
The world has an estimated 250 billion metric tons of K2O resources.
Potash refers to a variety of K-bearing minerals
There, some 30 saline minerals are known
Potash deposits, i.e. natural concentrations of raw potash, consist of potassium salt
rock, predominantly made up of the potassium minerals:
Sylvite (KCl),
Carnallite (KMgCl3*6H2O),
Kainite (4KCl.4MgSO4.11H2O) and
Langbeinite (K2Mg2(SO4)3)
The formation of the potash deposits (Barrier theory“)
32@Hassan Z. Harraz
Evaporite Deposits
33. World Potash Mine Production 2003
0
1
2
3
4
5
6
7
8
9
10
Canada
Russia
Belarus
Germ
any
Israel
Jordan
United
States
United
Kingdom
Spain
China
Chile
Brazil
Ukraine
Millionmetrictons,K2O
Source: IFA
%oftotalproduction
78% of total K2O produced
33
17
15
13
0
5
10
15
20
25
30
35
33
@Hassan Z. Harraz
34. Potash Deposits in Dead Sea
K extracted from Dead Sea
The world’s largest reserve of potash in
the form of salt solutions is the Dead Sea
(up to 1 billion tonnes of K2O), which has
been used for potash production since the
beginning of the 1930s.
contains an estimated up to 1 billion
tonnes KCl
Israel and Jordon represented 11% of
world production in 2003
Today DSW operates on the Israeli side
and APC on the Jordanian side
Arab Potash, the only producer in Jordan
is being privatized
Dead Sea Works (DSW), with production
in Israel and recent acquisitions in Spain
and UK is the world’s 5th largest producer
Bromine is remarkably concentrated in
the Dead Sea to the extent of 0.4%
compared with 0.0064 % in ocean water.
K2Oproduction,‘000t
0
500
1000
1500
2000
2500
1994 1996 1998 2000 2002
Israel Jordan
34
@Hassan Z. Harraz
Evaporite Deposits
35. 5) Deposition from Borate Lakes
Source materials: The borax of
the lakes is considered to have been
leached from, surrounding igneous
rocks or to have been contributed
by magmatic hot springs.
Mineralogy: The chief boron
minerals of playas and brines are:
Borax (Na2B4O7.10H2O)
Colemanite (Ca2B6O11.5H2O)
Ulexite (Na2.2CaO.5B2O3.16H2O)
Searlesite
(3Na2O.B2O3.4SiO2.2H2O) is also
found at Searles Marsh
Magnesium borates are considered to be typical of marine conditions and calcium borates of lake-bod
deposits.
Most borates of commerceare obtained from lakes, lake-bed deposits,or dry lakes.
Borate lakes are relatively uncommon, but several are known in California, Nevada, Oregon, Tibet, Argentina,
Chile, and Bolivia.
Borax and other boron-containing minerals are mined from evaporite lake deposits in Death Valley and
Searled and Borax Lakes, all in California; and in Argentina, Bolivia, Turkey, and China.
Formerly, most of the borax in the United States was obtained from lake waters in California and Nevada or
from playas.
Subsequently, borax was made less expensively from colemaniteand ulexite, and later from kernite. At
present, the only lakes yielding commercialborax are Searles and Owens, in California, where it is extracted
in conjunction with other salts.
Uses:
Borax has a wide variety of uses. It is a component of many
detergents, cosmetics, and enamel glazes. It is also used to make
buffer solutions in biochemistry, as a fire retardant, as an anti-
fungal compound for fiberglass, as an insecticide, as a flux in
metallurgy, and as a precursor for other boron compounds.
35
@Hassan Z. Harraz
Evaporite Deposits
36. Borate and Bromine Deposition
Minor quantities of borates and bromine are obtained from
marine salts. Although borates are mostly formed under other
conditions, some are precipitated along with potassium
minerals from marine residual liquids.
Bromine is also deposited from residual liquids of seawater.
The carnallite of Stassfurt contains 0.2 % bromine, which is
extracted in Germany during the refining of the potash salts.
Bromine is remarkably concentrated in the Dead Sea to the
extent of 0.4% compared with 0.0064 % in ocean water.
Most bromine, however, is a by-product of salt, from salt
brines and seawater.
Example: Boracite and other borates occur in the potash salt
of Germany in association with carnallite and the overlying
potash minerals.
36@Hassan Z. Harraz
Evaporite Deposits
37. Compared between Marine and Continental evaporites
Marine evaporites Continental evaporites
Marine Environments:
Coastal
Mud flats – Sabkhas
Salt pans
Barried basins
can be described as ocean or sea water deposits
(solutions derived from normal sea water by evaporation
are said to be hypersaline)
Shallow basin with high rate of evaporation: e.g. Gulf of
Mexico, Persian Gulf, ancient Mediterranean Sea, and
Red Sea.
Marine evaporites tend to have thicker deposits.
Marine evaporite deposits are widespread.
In North America, for example, strata of marine
evaporites underlie as much as 30% of the land
area.
The most important salts that precipitate from sea water:
Gypsum, Halite, and Potash salts {Sylvite (KCl),
Carnallite (KMgCl3 * 6H2O), Langbeinite
(K2Mg2(SO4)3), Polyhalite (K2Ca2Mg(SO4)6 * H2O),
Kanite (KMg(SO4)Cl * 3H2O), and Kieserite (MgSO4)}
Huge marine evaporite deposits were laid down in the
Seas and oceans during the Permian and Miocene
Epochs.
Marine evaporites produce:
Most of the salt that we use.
The gypsum used for plaster.
Continental Environments:
Saline Inland lakes:
Salt lakes
Alkali (or Soda) Lakes
Playa lakes
Perennial lakes
Bitter (or Sulfate) Lakes
Potash Lakes
Borate Lakes
Groundwater
Springs
The layers of salts precipitate as a consequence of evaporation:
Salts that precipitate from lake water of suitable
composition include: Sodium carbonate (Na2CO3), Sodium
sulfate (Na2SO4), and Borax (Na2B4O7.1OH2O).
The most important salts that precipitate from lake: Blödite, Borax
(Na2B4O7.1OH2O), Epsomite (MgSO4.7H2O), Gaylussite,
Glauberite, Mirabilite, Thenardite and Trona
(NaHCO3.Na2CO3.2H2O).
Continental deposits may also contain Halite, Gypsum, and
Anhydrite, and may in some cases even be dominated by these
minerals.
Huge evaporite deposits of Sodium carbonate were laid down in
the Green River basin of Wyoming during the Eocene Epoch.
Oil shales were also deposited in the basin.
@Hassan Z. Harraz
Evaporite Deposits
37
38. Lakes Seawater
1) CalciteCaCO3 and Magnesite (MgCO3 ) 1) Calcite(CaCO3) and Dolomite (CaMg(CO3 )2
2) CaSO4 precipitates next. 2) Gypsum:
Gypsum precipitates:
Gypsum (<42°C) or Anhydrite (>42°C).
3) NaCO3 precipitates next as:
3.1) Borax (Na2B4O7·10H2O or
Na2[B4O5(OH)4]·8H2O)
3.2) Borates
3.3) Nitrates
3.4) Natron (Na2CO2.10H2O)
3.5) Trona (NaHCO3.Na2CO3.2H2O)
4) NaSO4 precipitates
5) MgSO4 and Epsomite/ Epsom salts
(MgSO4.7H2O) precipitates
3) Halite:
Precipitates if 86-94% of original seawater
has been removed
Brine (solution) is very dense
6) NaCl saltern is left. These are fairly
common (Great Salt Lake)
7) MgCl2 and CaCl2 are precipitates
4) Potassic salts:
Precipitate if > 94 % of original seawater
has been removed
So: ionic strength (potential) of
evaporating seawater has a strong control
over minerals that form
Compared between Evaporation Sequence of Seawater and Lakes
IncreasingEvaporationRates
Decreasingorderofsolubility
The
first
phase
@Hassan Z. Harraz Evaporite Deposits 38
39. Calcium Sulfate Deposition
Calcium sulfate may be deposited either in
the form of gypsum Gypsum (<42°C) or
anhydrite (>42°C), depending upon the
temperature, pressure, and salinity of the
solution.
When the water has been evaporated to
about 70% of its original volume, calcium
sulfate starts to separate. At the
temperatures of evaporation of marine
basins, much gypsum will always be
deposited first if the temperature is <42°C,
and that marine beds of pure anhydrite
imply either that the early deposited
gypsum was converted to anhydrite or that
deposition occurred above the conversion
temperature of >42°C.
Equilibrium temperature for the reaction
CaSO4*2H2O CaSO4 + 2H2O(Liq. Sol.)
is a function of activity of H2O of the
solution.
Anhydrite can be hydrated back to
gypsum upon uplift and exposure to low-
salinity surface waters.
Resulting Products.
Calcium sulfate deposition occurs in:
1) Beds of relatively pure gypsum or
anhydrite from a few meters to
many hundreds of meters in
thickness (gypsum beds
constitute one of the most
important nonmetallic resources
and anhydrite finds little use);
2) Gypsum beds with impurities of
anhydrite;
3) Alabaster, a softer and lighter
variety of gypsum; and
4) Gypsite, an admixture with dirt.
5) The beds are generally
interstratified with limestone or
shale, and they are commonly
associated with salt.
@Hassan Z. Harraz
Evaporite Deposits
39
42. Economic importance of evaporites
Evaporites are important economically because of
their mineralogy, their physical properties in-situ,
and their behaviour within the subsurface.
Evaporite minerals, especially nitrate minerals, are
economically important in Peru and Chile. Nitrate
minerals are often mined for use in the production
on fertilizer and explosives.
Thick halite deposits are expected to become an
important location for the disposal of nuclear
waste because of their geologic stability,
predictable engineering and physical behaviour,
and imperviousness to groundwater.
Salt Domes: salt formations are famous for their
ability to form diapirs, which produce ideal
locations for trapping petroleum deposits.
Evaporite minerals start to precipitate when their concentration in water reaches
such a level that they can no longer exist as solutes.
The minerals precipitate out of solution in the reverse order of their solubilities,
such that the order of precipitation from sea water is
Calcite (CaCO3) and dolomite (CaMg(CO3)2)
Gypsum(CaSO4-2H2O) and anhydrite (CaSO4).
Halite (i.e. common salt, NaCl)
Potassium and magnesium salts
The abundance of rocksformed by seawater precipitation is in the same order
as the precipitation given above. Thus, limestone (calcite) and dolomite are
more common than gypsum, which is more common than halite, which is
more common than potassium and magnesium salts.
Evaporites can also be easily recrystallized in laboratories in order to investigate
the onditions and characteristics of their formation.
Major groups of evaporite minerals
More than eighty naturally occurring evaporite minerals have
been identified. The intricate equilibrium relationships among these
minerals have been the subject of many studies over the years. This
is a chart that shows minerals that form the marine
evaporite rocks, they are usually the most common
minerals that appear in this kind of deposit.
Hanksite, Na22K(SO4)9(CO3)2Cl, one of the few
minerals that is both a carbonate and a sulfate
Mineral class
Mineral
name
ChemicalComposition Rock name
Halites
(or
Chlorides)
Halite NaCl Halite; rock-salt
Sylvite KCl
Potash Salts
Carnallite KMgCl3 * 6H2O
Kainite KMg(SO4)Cl * 3H2O
Sulfates
Polyhalite K2Ca2Mg(SO4)6 * H2O
Langbeinite K2Mg2(SO4)3
Anhydrate CaSO4 Anhydrate
Gypsum CaSO4 * 2H2O Gypsum
Kieserite MgSO4 * H2O --
Carbonates
Dolomite CaMg(CO3)2 Dolomite, Dolostone
Calcite CaCO3 Limestone
Magnesite MgCO3 --
42
@Hassan Z. Harraz
Evaporite Deposits
43. Salt Extraction Technologies
Today, there are four methods used to produce dry salt based on the method of recovery :
(a) Surface Mining
(b) Underground mining: Also known as rock salt mining, this process involves conventional
mining of the underground deposits through drilling and blasting whereby solid rock salt is
removed. Mining is carried out at depths between 100 m to more than 1500 m below the
surface.
(c) Solution mining: Evaporated or refined salt is produced through solution mining of
underground deposits. The saline brine is pumped to the surface where water is evaporated
using mechanical means such as steam-powered multiple effect or electric powered vapour
compression evaporators. In the process, a thick slurry of brine and salt crystals is formed.
(d) Solar evaporation method (Normal evaporation): This method involves extraction of salt
from oceans and saline water bodies by evaporation of water in solar ponds leaving salt crystals
which are then harvested using mechanical means. Solar and wind energy is used in the
evaporation process. The method is used in regions where the evaporation rate exceeds the
precipitation rate.
More than one third of the salt production worldwide is produced by solar evaporation of sea water or
inland brines (Sedivy, 2009). In the salt crystallization plants, saturated brine or rock salt and solar salt
can be used as a raw material for the process. A summary of the possible process routes for the
production of crystallized salt based on rock salt deposits is shown in Fig.2. Processes that are used
in the production of vacuum salt from sea water or lake brine as a raw material are shown in Fig.3.
43@Hassan Z. Harraz
Evaporite Deposits
44. 1) Technology of the Salt (NaCl) Production
Fig.2. Processes for production of crystallized salt based on rock salt deposits (Westphal et al., 2010)
Underground mining
44@Hassan Z. Harraz
Evaporite Deposits
45. i) Surface Mining
iii) Solution mining:
two wells
selective dissolution
hot leaching
well
45@Hassan Z. Harraz
Evaporite Deposits
48. 1) Technology of the Salt (NaCl) Production
Fig.3. Processes for salt production from brine (Westphal et al., 2010)
Solar evaporation method
(Normal evaporation):
Pond
Marsh
48@Hassan Z. Harraz
Evaporite Deposits
50. Brines form by strong evaporation.
These ponds on the shores of Great
Salt Lake are sources of magnesium
as well as salt.
@Hassan Z. Harraz
Evaporite Deposits
50
53. Types of Salt
Finely ground powders and coarse, irregular chunks in rainbow hues – deep, crystalline
black, iron red, rose pink, fire red and sea grey.
1) TABLE SALT
2) KOSHER SALT
3) SEA SALT
4) HIMALAYAN PINK SALT
5) CELTIC SEA SALT
6) FLEUR DE SEL
7) KALA NAMAK
8) FLAKE SALT
9) BLACK HAWAIIAN SALT
10) RED HAWAIIAN SALT
11) SMOKED SALT
12) PICKLING SALT
@Hassan Z. Harraz
Evaporite Deposits
56. Calcium Carbonate Deposits
Calcium and magnesium carbonate give rise to deposits of
limestones, dolomite, and magnesite.
Calcium Carbonate Deposits may be of:
i) Chemical/inorganic origin (by evaporation)
ii) Organic/biogenic origin (by organism)
Calcium Carbonate Deposits are the most common type of
Chemical/inorganic sediment forming today by evaporation
process as well as Organic/biogenic origins.
Calcium Carbonate Deposits are formed by
i) evaporation process (chemical precipitation/ usually fine
grained)
ii) Organic/biogenic origin (grain size depending upon type of
organism).
Calcium Carbonate Deposits may be formed from:
i) Marine saline water (sea and ocean, lakes, inland lakes) .
ii) Marine fresh water origin
56@Hassan Z. Harraz
Evaporite Deposits