CIL Cyanidation Gold Extraction Process Analysis

High Efficiency and Economy: CIL Process Stands Out

In the field of gold mineral processing, the CIL (Carbon - in - Leach) cyanidation gold extraction process stands out for its high efficiency and economic advantages, becoming one of the mainstream technologies for processing refractory gold ores. This process combines cyanide leaching with activated carbon adsorption, significantly shortening the gold extraction cycle and increasing the gold recovery rate, injecting strong impetus into the development of the gold industry.

Ore Pretreatment: Laying the Foundation for Gold Extraction

The CIL cyanidation gold extraction process begins with ore pretreatment. The mined gold ore needs to be crushed and ground first, reducing the ore particle size to a standard suitable for leaching. Generally, the ore needs to be ground to less than 0.074mm to ensure that gold minerals are fully exposed and can come into contact with the cyanide solution. The ground pulp then enters a thickener for concentration, appropriately increasing the pulp concentration to create conditions for subsequent cyanide leaching.

Cyanide Leaching: The Core Chemical Reaction

Cyanide leaching is the core of the CIL process. The pulp is transported to the leaching tank, and a cyanide solution (such as sodium cyanide) is added. Under alkaline conditions and with aeration and stirring, gold reacts chemically with cyanide to form soluble gold - cyanide complexes. During this process, oxygen plays an oxidizing role, accelerating the dissolution of gold. To ensure the leaching effect, parameters such as the cyanide concentration, pulp pH value, reaction temperature, and stirring speed need to be strictly controlled.

Activated Carbon Adsorption: Capturing Gold - Cyanide Complexes

Activated carbon adsorption follows the leaching step. Special activated carbon particles are directly added to the leaching tank. With their large specific surface area and rich pore structure, they quickly adsorb the gold - cyanide complexes in the pulp. The activated carbon flows with the stirring in the pulp, continuously contacting the gold - containing solution until it reaches adsorption saturation. Subsequently, the gold - loaded activated carbon is separated from the pulp using a screen, and the remaining tailings pulp enters the tailings treatment system.

Gold Recovery: From Activated Carbon to Gold Ingot

The gold - loaded activated carbon undergoes processes such as desorption and electrolysis to recover gold. During desorption, the gold - loaded activated carbon is placed in a high - temperature and high - pressure desorption column. A high - concentration cyanide solution and sodium hydroxide solution are used to strip the gold - cyanide complexes from the activated carbon, forming a gold - rich solution. The gold - rich solution enters the electrolytic cell, and through electrolysis, gold ions are reduced and deposited on the cathode, finally obtaining high - purity gold mud, which can be smelted to obtain gold ingots.

Advantages and Challenges Coexist

The CIL cyanidation gold extraction process has significant advantages. It realizes simultaneous leaching and adsorption, reducing the process flow and equipment investment; it has strong adaptability to refractory gold ores such as fine - grained disseminated and carbon - bearing ores, effectively improving the gold recovery rate; and its high degree of automation can reduce labor costs and increase production efficiency. However, this process also faces environmental challenges such as the toxicity of cyanide and tailings treatment. The industry is constantly exploring non - toxic gold leaching agents and harmless tailings treatment technologies to promote the green upgrading of the CIL process.