Mineral ProcessingDepressant Agents

Depressant Agents

Inorganic depressants like sodium cyanide and sodium metabisulphite are used to suppress iron sulfide and zinc minerals, with hydrated lime adjusting pH for optimal recovery and selectivity during lead flotation from lead-zinc ores.

Product Description BenefitsApplications
Hydrated LimeCalcium Hydroxide (Ca(OH)₂)Hydrated lime is effective in adjusting and maintaining the pH levels in mineral processing circuits, creating optimal conditions for the flotation of minerals. Aids in the flocculation of fine particles, promoting better sedimentation rates in thickening and clarifying processes. Reacts with acidic components in the ore, neutralising them and preventing corrosion of equipment and minimizing environmental impacts. helps in the removal of sulfur dioxide from flue gases in smelting processes, reducing sulfur emissions and enhancing process efficiency. Hydrated lime can be used to condition slimes, reducing their negative impact on flotation and improving mineral recovery.Used to adjust the pH of flotation slurries, enhancing the flotation of valuable minerals while depressing unwanted gangue minerals. Promotes the aggregation of fine particles, aiding in the desliming and thickening processes and improving efficiency of solid-liquid separation. Acts as a depressant for specific minerals, for the flotation of minerals. Used in water treatment to adjust pH and remove hardness, making the water suitable for processing and recycling in mining operations. In the production of sulfuric acid from pyrite ores, hydrated lime is used to neutralise sulfuric acid generated during the roasting process. Used to neutralise acidic water and treat mine drainage. Used in the stabilisation of mine tailings and waste rock, enhancing their mechanical properties and reducing environmental risks.
Sodium CyanideSodium Cyanide (NaCN)Sodium cyanide is highly effective in dissolving gold and silver from ores, leading to high recovery rates. Targets precious metals, minimising the dissolution of other minerals, which enhances the purity of the recovered metals. Cost-effective for large-scale operations due to its high efficiency and effectiveness. Cyanidation process is well-established and widely used, meaning that there is extensive knowledge, experience, and infrastructure supporting its use.Gold and Silver Extraction (Cyanidation). Electroplating. Used to depress pyrite and other sulfides.
Sodium MetabisulphiteSodium metabisulphite (Na₂S₂O₅)Sodium metabisulphite is effective in selectively depressing certain minerals, particularly iron sulfides such as pyrite, during the flotation process, enhancing the separation and recovery of valuable minerals. Acts as a reducing agent that can help in removing dissolved oxygen from mineral slurries, which can be beneficial in preventing the oxidation of certain minerals and flotation reagents. Sodium metabisulphite is relatively inexpensive and easy to handle, making it a cost-effective choice for mineral processing operations. Compared to other chemical depressants, sodium metabisulphite has a relatively lower environmental impact when used and disposed of properly.Used to depress iron sulfides such as pyrite (FeS₂), pyrrhotite (Fe₁₋ₓS), and arsenopyrite (FeAsS) in flotation circuits. detoxify cyanide in the wastewater from gold and silver extraction processes, converting cyanide to less harmful compounds. Acts as an antioxidant to prevent the oxidation of sulfide minerals during the flotation process. Treatment of water used in mineral processing, sodium metabisulphite is used for dechlorination (removal of chlorine) and clarification purposes.
Sodium MonosphateMonosodium phosphate (MSP, NaH₂PO₄)Sodium monophosphate can act as a buffering agent to adjust and stabilize the pH of mineral slurries. This is crucial in flotation processes where maintaining an optimal pH is necessary for the effectiveness of collectors, frothers, and depressants. Can function as a dispersant, helping to keep fine particles in suspension, thereby preventing the aggregation of minerals. This improves the separation efficiency in processes like flotation. Can aid in the selective flocculation of certain minerals, which can enhance the separation process by selectively aggregating the desired minerals while leaving unwanted minerals dispersed.Used in flotation to modify the pH and improve the dispersion of particles. Acts as a dispersant in the grinding process to prevent the clumping of fine particles. Can help manage slime formation.
Zinc SulphateZinc Sulfate (ZnSO₄)Used in froth flotation processes to enhance the recovery of valuable minerals. It acts as a depressant for certain sulfide minerals, reducing their flotation while enhancing the flotation of others. Zinc sulfate can help control the formation of slimes by precipitating iron and other contaminants that would otherwise interfere with flotation. Helps in increasing the grade of ore concentrates by selectively depressing the unwanted minerals, thereby improving the overall quality and value of the extracted material. Used to control iron contamination in the ore, which is crucial for the subsequent processing steps, particularly in the extraction of copper and other base metals.In the flotation of copper and lead ores, zinc sulfate is often used to depress iron sulfides and pyrite, thus enhancing the flotation of copper and lead minerals. Used to activate zinc ore for flotation, and simultaneously, it depresses other minerals, ensuring that zinc is selectively recovered. In gold and silver processing, zinc sulfate can be used to depress pyrite and arsenopyrite, enhancing the recovery of precious metals. It is used in water treatment processes to precipitate heavy metals and control water quality, ensuring that the water used in mineral processing is free from contaminants. Zinc sulfate can help in adjusting the pH of flotation solutions, optimizing the flotation conditions for different minerals.
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