Method for recovering gold solution from cyanide leached pulp

Recovering gold solution typically containing a variety of solid-liquid separation technology from cyanide leaching pulp, when added to the wash water to solid-liquid separation, the solid-liquid separation and washed three kinds of methods commonly used gold solution.
1. Decanting and washing method According to the method of separating gold-containing solution, it can be divided into:
1) Batch method The cyanide slurry after leaching is sent to the clarification tank. After the slurry is clarified, the gold-containing solution is extracted by a siphon with a float and sent to the replacement operation. The remaining concentrated slurry is returned to the agitation leaching tank and the dilute sodium cyanide solution is added to continue the leaching. This operation can also be realized by a thickener, that is, the cyanide slurry is sent to the thickener, and the overflow (gold-containing solution) is sent to the replacement operation, and the thick product is returned to the stirring leaching tank and the diluted sodium cyanide solution is leached. Then, the re-leached slurry is sent to a clarification tank or a thickener. This is repeated several times until the solution contains a small amount of gold.
Intermittent decantation washing is rarely used in industry because of its long operating time, large amount of solution used and large floor space.
2) Continuous method This method is suitable for the treatment of materials that are easy to precipitate. It is washed in a countercurrent manner, that is, the slurry flows in from the front to the back, and the washing liquid returns from the back to the front, and the washing liquid used for each slurry thickening is the overflow of the next thick. The continuous washing method can be further divided into:
1 Single-layer thickener continuous washing This method can be implemented by connecting several single-layer thickeners in series. The washed slurry is fed into the first thickener, and the ore is fed to the next thickener until the discharge of the last stage washing thickener is discharged as cyanide tailings. The wash water is added to the last thickener and flows countercurrently to the slurry.
This method is simple to operate, the gold washing rate is high, and it is easy to realize automation. However, due to the large land occupation and the need for multiple pump delivery of the slurry, the current production is not used much.
2 Multi-layer thickener continuous washing The structure of the multi-layer thickener is shown in the figure below. A center straight shaft 1 is placed in the center of the multi-layer thickener, and the truss 2 is fixed thereto. The cyanide slurry enters the 1 layer thickener through the feed port 3 and successively enters the II and III layers. The III layer of dense product is discharged from the discharge port 4. The washing liquid enters the washing slurry of the layer III thickener through the washing tube 5, overflows into the II compartment of the washing liquid tank 11, and then enters the washing slurry of the layer II thickener through the tube 7. The overflow of the layer II thickener enters the washing compartment 1 along the tube 8, and then enters the layer 1 thickener to wash the slurry through the washing liquid pipe 9. The overflow of the I layer thickener is the gold-containing noble liquid and flows out from the overflow tank 10.

2. Filtration and washing method When washing by filtration, a vacuum filter is usually used to separate the gold-containing noble liquid from the cyanide pulp. According to its operation, it can be divided into two types: continuous type and intermittent type. It is a continuous type of cylindrical vacuum filter and disk vacuum filter. It is a batch type framed vacuum filter and filter press, which is widely used in the selection.
The leached pulp is fed into a filter, and the gold-containing solution is subjected to the gravitational force in the filter to pass through the filter cloth, and the solid particles stay on the surface of the filter cloth to form a densely precipitated material, that is, cyanide tailings.
When the concentration of the slurry to be fed into the washing operation is small, in order to improve the washing efficiency and the filtering ability of the filter, a single-layer thickener is generally added before the washing.
3. Combined washing method A combined process consisting of multiple single-layer (or multi-layer) thickeners and filters. The first few stages are counter-flow washing for thickeners. The latter stages are washed by the filter, and the filtrate discharged from the filter can be returned to the previous stage of the countercurrent washing process as washing water.
The washing water is mixed with the first-stage washing thickener, and is fully stirred and then fed into the second countercurrent washing thickener. The discharge of the second stage countercurrent washing thickener is directly fed to the third stage washing filter, and the filtrate of the filter enters the first stage washing thickener as washing water. The filter cake is discharged as cyanide tailings.
4. Fluidized Washing Method Fluidized Washing The gold-containing solution is separated from the cyanide slurry by a washing column. The wash column (below) is a fine, round, hollow column. The slurry enters from the top and the washing liquid is fed from the interface between the washing section and the compression section. Solid ions settle to the bottom of the column and exit the discharge tube, while the gold-containing solution overflows from the top of the column. A slurry distributor, a washing liquid distributor and a discharge conveying device are installed in the washing column. However, such washing equipment has not been widely used because the production process is not stable enough.

In recent years, some foreign gold mines use a high-efficiency thickener, which combines the performance of sedimentation and filtration. It is characterized in that the slurry is first degassed, then loaded into a thickener mixing tank, and the flocculant is added to the mixing tank in stages. Each section is equipped with an impeller for mixing and mixing, and the amount of flocculant added in each section is controlled to be evenly distributed. After the slurry is mixed with the flocculant, it is precipitated into the lower part of the mixing tank and then enters the upper part of the grit. The grit remains in the grit layer and is pumped out by the motive, and the liquid is filtered through the grit layer and then rises. The main disadvantage of the equipment is that the residence time of the slurry in the tank is short, so the requirements on the process requirements (such as the ore size) are strict, and a good test device is required. However, the device has the advantages of small size, high efficiency, low investment, and the like, and has the potential to replace the conventional thickener.

Calcium Carbonate

According to the different production methods of calcium carbonate, calcium carbonate can be divided into Heavy Calcium Carbonate, light calcium carbonate, colloidal calcium carbonate and crystalline calcium carbonate. White solid, tasteless and odorless. There are two forms of amorphous and crystalline. The crystal type can be divided into orthorhombic crystal system and hexagonal crystal system, which are columnar or diamond-shaped.