There are many methods for extracting gold from gold ore, each with its own characteristics and applicable conditions. Common methods for gold extraction from gold ore include gravity separation, flotation, cyanide leaching, chlorination leaching, cyanide flotation, pressure oxidation leaching, etc. Below is a brief introduction to several common gold extraction methods and their recovery rates:
Principle: Extract gold by using gravity separation method based on the fact that gold has a higher density than other minerals.
Recovery Rate: The recovery rate is relatively low, usually between 30% to 50%, and is greatly influenced by the ore nature and equipment technology level.
Principle: Use bubbles added in the flotation cell to make gold ore particles adhere to the bubbles and float to the liquid surface, thereby separating gold ore from other minerals.
Recovery Rate: The recovery rate of flotation is usually relatively high, ranging from 60% to 90%, depending on factors such as ore grade, selection of flotation reagents, and optimization of flotation process.
Principle: Crushed gold ore is contacted with cyanide solution, and gold is dissolved in the form of gold cyanide. Then gold is adsorbed by activated carbon, followed by desorption of gold from activated carbon using sodium hydroxide or hydrochloric acid to obtain gold mud, which is then refined by electrolysis or chemical extraction.
Recovery Rate: The recovery rate of cyanide leaching is usually high, exceeding 90%, but this method poses environmental pollution and safety risks.
Principle: Crushed gold ore is contacted with chloride solution, and gold is dissolved in the form of chloride. Then gold is obtained through reduction reaction.
Recovery Rate: The recovery rate of chlorination leaching is usually high, exceeding 90%, and it is relatively more environmentally friendly compared to cyanide leaching. However, the equipment and process are complex, and the cost is higher.
Principle: Under high temperature and high-pressure oxygen environment, gold ore is contacted with alkaline oxygen-containing aqueous solution, and gold is dissolved in the form of oxide. Then gold is obtained through reduction reaction.
Recovery Rate: The recovery rate of pressure oxidation leaching is relatively high, usually exceeding 90%. However, it requires high equipment investment and energy consumption, which need to be considered for economic feasibility.
In summary, different gold extraction methods have their own advantages and disadvantages. Choosing the appropriate method requires comprehensive consideration of factors such as ore nature, process conditions, cost, and environmental protection.
