The mixing tank is used to add various reagents such as caustic soda or hydrated lime. These reagents can also be added in the ball mill stage or the agitating tank, and there is no fixed standard; the adjustment is based on the actual conditions of the ore.
During the carbon slurry process, the additives caustic soda or hydrated lime can be added at the stage of ore entering the ball mill; the dosage is determined based on the ore consumption and is not fixed.
The recommendation for a rectangular heap is to improve water permeability. To determine whether all the ore has been fully permeated, small barriers can be created on the surface of the heap, similar to paddy fields, and the water level in each barrier can be observed to assess the quality of permeation. In the initial […]
To determine whether a certain type of ore is suitable for cyanidation or flotation and reselection, visual assessment is followed by various targeted experiments to obtain various data, ultimately determining the optimal processing method through comprehensive evaluation.
The entire process of cyanide leaching for gold extraction is as follows: The cyanide process involves using a reagent to react with the ore, dissolving the gold from the ore into the reagent solution. The gold is then adsorbed and replaced, initially concentrated, and then refined through smelting to obtain the final product of gold […]
The methods for cyanide gold extraction are pit leaching, heap leaching, and carbon slurry adsorption (CIP or CIL), which allow thorough mixing of reagents and ore.
The “cyanide” in cyanide gold extraction refers to the cyanide ion content.
No, it is not possible. Large gold particles cannot be dissolved by the reagents. It is necessary to first use gravity separation to recover the free gold particles before cyanidation.
The fineness of the ore is closely related to the recovery rate. The optimal fineness varies for pool leaching, flotation, and carbon slurry. The degree of oxidation and the size of the gold also determine the fineness variation. In conclusion, different ores have different optimal processing methods.
Activated carbon adsorption cannot be determined by time; it can only be judged based on assay results. There is no specific time standard for this process.
The minimum requirements for carbon slurry cyanidation are grade and recovery rate. It is crucial to conduct experiments to determine the optimal processing method for the ore.
The height of the ore heap in heap leaching should be determined based on the characteristics of the ore, which can vary significantly. The slope should be managed accordingly. It is preferable to choose a flat terrain for the heap.
For heap leaching, simple washing of the activated carbon is sufficient for use, or adding a small amount of activating agent during the adsorption process is enough. It’s a simple process that doesn’t require special treatment, or you can simply provide the customer with high-quality water-washed carbon.
The standard for judging the quality of activated carbon is based on two factors. Firstly, the higher the iodine value, the better the adsorption capacity, and the more fragile the activated carbon, making it unsuitable for carbon slurry. Secondly, the amount of residue after the activation carbon which is burned should be minimal. The residue can […]
In ore processing, iron is not harmful or influential. Co-occurrence of iron and gold is quite common, and the specific recovery rate depends on the different types of ore. There are cases where iron content is high in gold-bearing iron oxide ore, yet the recovery rate is very good.
Bleach powder can neutralize chemical toxins.
Sulfide ore is a primary ore and can also undergo cyanidation. After fine grinding, it can be vat leached or processed with carbon slurry. If the fineness is not enough, for example, if it is not finely crushed, the leaching rate in heap leaching will be very low.
For separate silver processing, a concentration of 50 grams per ton or higher warrants the use of zinc wire or zinc powder for replacement. During smelting, a temperature of at least 1300 degrees Celsius is required. Both gold-containing and silver-containing materials can be melted at this temperature. It’s important to note that this temperature refers […]
Pit leaching, heap leaching, and cyanidation can all accommodate silver. If the silver content is high, the Merrill-Crowe process using zinc replacement can be employed to recover gold and silver. If the silver content is low, activated carbon is used.
There is no strict standard for sulfur content that represents its impact on the leaching rate. Generally, 4%-5% or higher sulfur content is considered relatively high, indicating a preference for flotation. However, many high-sulfur minerals still exhibit good leaching rates, so there isn’t a strict distinction criterion; judgment is typically based on individual experimental results.
Normally around 100 mesh, and if the permeability is good, slightly larger particles can also be used. The particle size for the crusher is generally 70-80 mesh and can be adjusted by changing the grinding time (or increasing the water level) to adjust the particle size, it’s recommended to keep it within 100 mesh.
Over 90% of the particles should pass through a 200-mesh sieve.
Testing the leaching solution once or twice a day is adequate. Monitoring the difference in gold content between rich and poor solutions indicates the adsorption by the activated carbon; a significant difference suggests effective adsorption. The leaching solution should be tested diligently, with tests conducted 1-2 times daily for pH, reagent concentration, and gold-silver content. […]
Depending on the production output and material conditions. It’s preferable for the dimensions to be rectangular, with the drainage outlet ideally positioned in the middle of the length. The height is determined based on the fineness and viscosity of the ore.
In theory, the solution can be circulated indefinitely. However, in special cases where harmful substances are present in the ore, it is advisable to replace the solution regularly.
Mechanical or manual feeding with agitation is required for the material in the leaching tank for vat leaching, and afterwards, it needs to be aerated.
The water usage for pit leaching is approximately 1:10 with the ore, while for heap leaching, it depends on the actual situation. Consumption mainly consists of daily evaporation and rainfall. Excess recovered water can be stored in reserve ponds.
The temperature should be above freezing. Long leaching times will occur at low temperatures, while high temperatures result in increased reagent consumption, both of which have drawbacks.
Uniform spraying of the leaching solution and continuous monitoring are used for assessment. The heap is also usually overturned in the later stages to ensure uniform leaching.
Extraction experiments generally last 24-48 hours. These experiments can be used to determine the alkaline and reagent consumption per ton of ore. The actual heap leaching period should be determined based on the oxidation level, particle size, and overall heap size of the ore.
Spraying should be frequent, but intermittent, and not continuous. It should not be done continuously.
Generally, for regular ore samples, 10 kilograms or more are required.
The optimal range for reagent concentration is generally between 0.2 and 7 parts per thousand. Silver nitrate testing is simple and fast, and it is used to adjust the dosage based on the test results. It’s recommended to add a small amount each time and repeat the process, rather than adding a large amount all […]
In the absence of obvious harmful elements, the suitable pH range is typically between 9 and 11. Excessively high pH values are detrimental and can affect the leaching rate. pH strips or small instruments are suitable for testing pH levels.
A high clay content will affect the leaching rate, mainly by affecting the permeability and air permeability of the ore heap. The solution can involve agglomeration, using small heaps, or even large-scale vat leaching to solve this problem.
For ores with good oxidation, they can be directly stacked, while hard ores are generally below 3 centimeters in diameter.
The main elements that affect the leaching rate are arsenic, carbon, copper, and excessively high sulfides. Excessive iron also has an impact. Ultimately, it depends on experimental data or adjusting auxiliary agents to improve efficiency.
Oxidized ores or relatively soft limonite, except for quartz vein sulfide ores, basically all gold-bearing minerals can be heap leached. For gold ores with good oxidation, they can be directly stacked for heap leaching. For slightly harder ores, they need to be crushed before heap leaching.