Percolation cyanide heap leaching

General percolation cyanide heap leaching

Containing the crushed gold ore or shipped directly to ground accumulation heap leaching heap certain way, then spray the surface of the heap cyanidation agent, percolation leaching agent uniformly from top to bottom by fixing ore heap, silver into the gold leaching solution In the process, the main processes include ore preparation, construction of heap leaching, building, leaching, washing, and gold and silver recovery.

a ore preparation

When the gold-bearing ore used for heap leaching has a large particle size, it is usually crushed first, and the crushing particle size is determined according to the nature of the ore and the embedding characteristics of the gold particles. The finer the size of the heap leached ore, the looser and more porous the ore structure, the higher the leaching rate of gold and silver during the leaching of the heap; however, the finer the particle size of the heap leaching ore, the smaller the leaching rate during heap leaching, and even the leaching of the leaching The process cannot be done. Therefore, in general leaching cyanide heap leaching, the ore can be broken to less than 10mm; when the ore contains less mud, the ore can be broken to less than 3mm.

b Construction of the heap immersion field

The leachate immersion field can be placed on a hillside, valley or flat ground, but requires 3% to 5% slope for flat land. After the ground is cleaned and leveled, anti-seepage treatment is required. The anti-seepage material can be blended with tailings, asphalt , reinforced concrete, rubber sheets or plastic films. The general method is to first compact or compact the ground, and then lay a polyethylene plastic film or a high-strength polyethylene sheet (about 3mm thick), or a linoleum felt or artificial felt, and the anti-seepage layer is required to not turn over and can withstand the mine. Pile pressure. In order to protect the anti-seepage layer, fine-grained waste rock and coarse-grained waste stone of 0.5-0.2 m thick are often laid on the cushion layer, and then the low-grade gold ore is transported to the heap immersion field for pile-up.

In order to protect the mine, drainage gullies should also be arranged around the heap immersion site. At the same time, a sump is provided in the heap leaching field to collect the leaching solution. The liquid collection ditch is generally an open groove lined with plastic. The immersion liquid flows into the sedimentation tank to make the slime settle, so that the immersion liquid entering the precious liquid pool is a clear solution. The heap immersion field can be used multiple times or only once. The cushion of the heap immersion field used at one time can be laid on the compacted foundation with a layer of about 0.5 m thick, and after compaction, the sodium carbonate solution is sprayed thereon to enhance its anti-seepage performance.

c pile up

Commonly used pile-up equipments include trucks, bulldozers (crawlers), cranes, and belt conveyors. The pile-up methods include multi-pile method, layering method, slope method, and hoisting method.

Multi-population method. The ore is first piled into a number of ore piles about 6 m high by a belt conveyor, and then leveled with a pile. When the belt conveyor is used for pile-building, particle size segregation will occur, and the coarse particles will roll to the edge of the pile, and the surface ore will be crushed and compacted by the bulldozer. Therefore, the channeling phenomenon occurs when the leaching solution is leached, and as the immersion liquid flows, the slime easily precipitates and blocks the pores in the heap, making it difficult for the solution to percolate from the inside of the heap and easily from the coarse margin of the edge of the heap. Flowing, even in severe cases, it will even smash the slope of the heap, making the heap immersed unevenly and reducing the leaching rate of gold.

Multi-layer method. First pile up with loader trucks, pile a layer of ore and then level it with a bulldozer, stack it up one layer at a time, until it reaches the height of the required pile. The advantage of this pile-up method is that the particle size deviation phenomenon can be reduced, and the ore size in the heap is relatively uniform, but each layer of ore can be crushed and compacted by trucks and bulldozers, and the percolation of the ore pile is poor. .

Slope method. First use a waste rock to build a slope to control the use of trucks for transportation. Generally, the slope is 0.6-0.9m higher than the pile. The ore was then unloaded by truck to both sides of the ramp and then leveled on both sides with a pile. When the method is built, the truck does not crush the compacted ore. The pressure of the bulldozer is smaller than that of the truck, and the impact on the porosity of the heap is small. After the pile is built, the waste rock slope is leveled and the waste rock is loosened with a ripper. This pile-up method can obtain a heap with a relatively uniform porosity, but has a large area.

Hoisting method. The bridge crane is used to mine the mine, and then the electricity is used for leveling. The advantage of this method can eliminate the mining ore compaction of the mining machinery. The percolation of the ore heap is good, and the immersion liquid can pass through the heap more uniformly, and the proposed rate is higher. However, this method requires the construction of a crane track, which has a large investment in infrastructure and a slower pile-up speed.

d Leaching and washing

After the heap is built, the heap is generally washed with saturated lime water. When the pH of the washing liquid is close to 10, the human solution is sent to the solution. The liquefied leaching agent is pumped to the pipe on the surface of the heap by a pump, and then the spray agent is evenly sprayed on the surface of the heap through a shower to uniformly percolate and pass through the heap for gold and silver. Commonly used showers include rockers, ejector and drips. The structure of the shower should be simple, easy to maintain and repair, spray radius is large, spray evenly, spray droplets are thicker to reduce evaporation and reduce water heat loss. In the leaching process, the liquid supply force is uniform and stable, and the spray speed of the solution is generally 1.4-3.4 m11 (m2·.).

After the diafiltration cyanide heap leaching, it was washed several times with fresh water. If time permits, the washing liquid should be drained after each washing and then washed again to increase the washing rate. The total amount of water used for washing is determined by factors such as the evaporation loss of the wash water and the water content of the tailings.

e Gold and silver recycling

The gold content in the precious liquid obtained by percolation and liquefaction heap leaching is often low, and gold and silver can be recovered by activated carbon adsorption or zinc displacement method, but high recovery rate of gold and silver can be obtained by activated carbon adsorption method. Generally, 4 to 5 activated carbon columns are used to enrich gold and silver, and the obtained noble liquid is desorbed to deliver electricity, and the molten gold is smelted to obtain finished gold. The lean liquid after de-gold and silver is adjusted to the concentration of the scent and the pH value, and then returned to the heap for leaching and leaching.

Auto Pistons

Combustion cycle: Pistons are always moving up and down, as a piston moves upward, it compresses the air and fuel in the combustion chamber. Once this happens, the spark plug is used to ignite the fuel and air, and the resulting explosion pushes the piston back down