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Biominindsdsds_and_bioleaching.pp bioleachtx
Biomining is an innovative and eco-friendly method for extracting metals from low-grade ores using microorganisms. It encompasses processes like bioleaching and biooxidation to enhance metal recovery, particularly for valuable metals such as copper, uranium, nickel, and gold. The technique not only promotes efficient metal extraction but also aids in the remediation of polluted sites.
Biominindsdsds_and_bioleaching.pp bioleachtx
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- 3. introduction Continuous depletionof Earth’s high-grade deposits of metals necessitates the need for innovative and economical ways of recovering metals from low-grade deposits. Ores with low metal content are not suitable for direct smelting but it is possible to extract metals economically using the activity of microorganisms.
- 4. biomining It isthe extraction of specific metal from their ores through biological means mostly by microorganisms. It is an effective and green technology to mine metals. The main aim of this technology is to utilize bioxidation and biotransformation to decompose the mineral matrix and exposed the entrapped valuable metals.m Its also a combination of chemical and physical methods. It is done in two steps that are: i. bioleaching ii. Bioxidation
- 5. Advantages of biomining It is cheap Reliable Efficient Environmentally friendly
- 6. Characteristics of bacteria usedin biomining Thermophilic Chemophilic Autotrophic
- 7. Most currentbiomining operations target valuable metals like copper, uranium, nickel, and gold that are commonly found in sulfidic (sulfur- bearing) minerals. Biomining techniques may also be used to clean up sites that have been polluted with metals.
- 8. Bioleaching Extraction ofmetals and ores using principle components of water,air and microorganisms which are readily found within the environment. It directly dissolves metal of interest. It involves the following processes
- 9. Cont… Heap leaching:freshly mined material is moved directly into heaps that are then bioleached. Dump leaching:low value ore or waste rock is placed in a sealed pit and then bioleached to remove more of the valuable metals from the waste pile. Agitated leaching: crushed rocks are placed into a large vat that is shaken to distribute the microbes and material evenly and speed up the bioleaching process.
- 10. process Low gradeore is dumped in a large pile (the leach dump) and a dilute sulfuric acid solution (pH 2) is percolated down through the pile. The liquid coming out at the bottom of the pile, rich in the mineral is collected and transported to a precipitation plant where the metal is reprecipitated and purified. The liquid is then pumped back to the top of the pile and the cycle is repeated. The most important microbes that are used, include iron-and Sulphur oxidizing chemolithotrophs.
- 13. bioxidation Involves oxidationof metal ore inorder to reach to metal of interest. The metal of interest is made more accessible or enriched in the material left behind due to the processes of microbial reactions, in the presence of oxygen and nutrients.
- 14. Cont… Biooxidation alsouses microorganisms, not to extract metals, but to make the metals ready for extraction. Oxidation is the chemical reaction in which an element is changed by the addition of oxygen. Rust is an example of the oxidization of iron. Biooxidation is mainly used in gold mining. Gold is often found in ores with gold particles scattered throughout, called refractory ores, and the small particles of gold are covered by insoluble minerals. These minerals make the extraction difficult. Therefore, microorganisms that can "eat away" at the mineral coating are used to pre-treat the gold ores before they can be extracted.
- 15. Talvivaara Bioheapleach, Finland Theworld’s first for Nickel Centred on two polymetallic deposits, Kuusilampi and Kolmisoppi in Eastern Finland Natural, cost-effective and environmentally friendly Process done in two stages 1. Crushing 2. Bioheapleaching 3. Meatal recovery
- 16. Bioheapleaching Metal oresare leached from ore by bacterial action Bacteria used grow naturally in the ore and the company reports up to 98% recovery rates from metal ore to solution Operated In two stages 1. Primary heap with a residence time of 1.5 years 2. Secondary pad residence of 3.5 years
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- 20. Metal recovery Threetypes are recovered 1. Copper sulphide 2. Zinc sulphide 3. Nickel copper sulphide
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