Gold mines are the primary source for the extraction of the precious metal gold. Given gold’s high value and low yield, the choice of extraction methods is especially critical. Among the commonly used gold extraction techniques, the leaching process is widely applicable and efficient, thus making it a staple technique. The leaching process of gold ores is a critical step in extracting the gold content, and it typically necessitates specialized equipment. Some common gold leaching equipment includes:
The primary function of grinding equipment is to reduce the ore to a specific particle size, enhance the exposure of gold within the ore, and prepare it for subsequent leaching. In the gold leaching process, commonly employed grinding equipment includes ball mills and rod mills. Ball mills are utilized to finely grind the ore to a size conducive to leaching. For coarse grinding, a lattice-type ball mill is an option, whereas for secondary or fine grinding, an overflow ball mill is preferred. Rod mills, also utilized for grinding, employ long rods instead of balls, making them appropriate for specific types of ores.
The gold leaching tank is the primary location for the leaching process, where the slurry is mixed with a leaching agent (such as sodium cyanide solution) to dissolve the gold. Common types of leaching tanks include: mechanically stirred tanks, which use a mechanical stirrer to thoroughly mix the slurry and leaching agent. Air-agitated tanks, which employ compressed air to fluidize the slurry, enhancing contact between the slurry and the leaching agent.
During the cyanide leaching process, specialized equipment is used to add cyanide and maintain optimal chemical reaction conditions to enhance the dissolution rate of gold. Common gold cyanidation equipment includes the cyanide tank, specifically designed for cyanide leaching and suitable for continuous or batch operations. The cyanide leaching machine is an automated device that enhances leaching efficiency.
Activated carbon columns are utilized to adsorb dissolved gold from leachate and concentrate it via physical adsorption. These columns are pivotal equipment in both the Carbon Slurry Method (CIP) and Carbon Leaching Method (CIL).
The primary function of gold mine filtration equipment is to separate the leached slurry into solid and liquid phases, recover solid slag, and supply clear liquid for subsequent processing. Common equipment includes vacuum filters, which are utilized to filter the leached slurry and separate solids from liquids. Filter presses are also employed, applying pressure to expedite the filtration process.
The function of gold ore thickener equipment is to increase the solid content in the slurry, reduce the amount of liquid in the subsequent processing, and lower energy consumption and costs. The commonly used concentration equipment includes a thickener, which is used to increase the solid content of the slurry and reduce the amount of liquid required for subsequent processing. There is also a plate and frame filter press, which works by using a plate and frame structure and high-pressure pressing to achieve efficient concentration of slurry and solid-liquid separation.
The purpose of washing equipment is to clean activated carbon that has adsorbed gold, remove impurities, and prepare for gold extraction. Commonly used washing equipment includes washing tanks and two-layer (or three-layer) washing thickeners.
The function of gold mine electrolysis equipment is to extract and deposit gold adsorbed on activated carbon into gold nuggets through electrolysis. The commonly used equipment is an electrolytic cell, which works by reducing and depositing solid gold from a solution containing gold ions on the cathode through electrolysis.
The function of gold ore heat treatment equipment is to roast certain types of gold ore to remove sulfides, reduce cyanide consumption, and improve gold leaching rate. The commonly used equipment is a roasting furnace, which is used to roast sulfur-containing gold ores, remove sulfur, and separate gold from other minerals.
Besides the aforementioned gold leaching equipment, there are auxiliary devices like pumps and valves. Pumps transport the slurry and leaching agent to different processing stages. Pipelines and valves form the network for material and information flow in the entire leaching process, ensuring a smooth and safe flow.
These devices can be used individually or in combination to accommodate varying gold ore characteristics and leaching process needs. When selecting leaching equipment, factors like ore properties, desired leaching efficiency, environmental regulations, and economic benefits must be considered.
The leaching process is a frequently employed gold extraction technique in the beneficiation of gold ores. The process selection should be guided by beneficiation tests, and similarly, equipment selection should be based on these test results. Selecting the right equipment ensures the successful execution of the beneficiation process and secures the recovery rate.
