How mercury is applied to a mercury plate

A mercury solution is applied to the silver-plated surface of the mercury plate, and the slurry flows over the plate and comes into contact with the mercury. The mercury is added to the slurry after the operation has begun. After the amalgamation operation has been carried out for some time, a layer of mercury paste is conveniently retained on the mercury surface, which is promptly scraped off.

External amalgamation is suitable for the treatment of gold-bearing polymetallic ores, and is mainly used to capture the coarse-grained gold. In the gold processing plant, amalgamating plate is mostly installed in the discharge of the ball mill to capture the coarse free gold in the mill products.

Cyanidation

Since 1887 applied to the extraction of gold and silver in mines, there has been nearly a hundred years of history, the process is relatively mature. Because of its high recovery rate, strong adaptability to the ore, can on-site real estate gold, so it is still one of the main ways of gold production.

Cyanidation can be divided into stirring cyanidation and percolation cyanidation. Stirring cyanidation is used to deal with re-election, amalgamation after the tailings and flotation of gold-bearing concentrates, or for the whole mud cyanidation; and percolation cyanidation is used to deal with flotation tailings and low-grade gold-bearing ore heap leaching and so on.

Conventional cyanidation is a very mature process, which includes the preparation of leaching raw materials; agitation cyanide leaching; countercurrent washing solid-liquid separation; leach solution purification and deoxidation; zinc powder replacement and pickling; melting ingot casting and other major operations.

a, leaching raw material preparation: usually the extracted ore by crushing, grinding (or beneficiation), prepared into a suitable cyanide leaching slurry. The fineness of grinding depends on the embedded characteristics of natural gold. For gold-bearing quartz vein ores, generally grinding to 60 ~ 70% -200 mesh; and sulfide minerals containing gold ores, more flotation enrichment, concentrate and then grinding to 90 ~ 95% -325 mesh; high arsenic-containing or magnetopyrite ores, it is taken to flotation concentrate roasting desulphurization arsenic, roasted sand cyanide; In addition, there are still high in charcoal and interfere with the cyanide leaching of the ores.

b, stirring cyanide leaching: in the slurry concentration of 35 ~ 50%, pH 10 ~ 10.5, cyanide concentration of 0.03 ~ 0.06% of the conditions, full stirring leaching for more than 24 hours. So that more than 95% of the gold is dissolved into gold-cyanide complex.

The agitation leaching tank has two kinds of mechanical agitation type and air agitation type.

c, countercurrent washing solid-liquid separation: in order to make the cyanide leach solution and gold dregs to be fully separated, generally using multiple single-layer or multi-layer concentrator composed of multi-stage countercurrent washing; the use of filtering machine for multi-stage filtering and washing; the use of multiple concentrators and filters composed of joint washing. The latter is more common in foreign countries, while the domestic is mainly used single or multi-layer concentrator for multi-stage countercurrent washing.

d, leach solution purification and deoxygenation: from the washing operation to get the leach solution (precious liquid), usually contains 70 ~ 80 ppm or even higher suspended solids. In order to prepare the conditions for the zinc powder replacement operation, it is necessary to reduce the suspended matter content in the precious liquid to 5-7ppm, and the oxygen content to 1ppm, so it is necessary to purify and deoxidize the precious liquid.

e, zinc replacement and pickling: with zinc replacement solution of gold-cyanide complex in the solution to precipitate gold precipitation precipitation. In order to make the zinc powder to get more effective replacement reaction, in the solution should keep about 0.005% of lead salt and 0.05% of cyanide concentration.

f, melting ingot: gold mud and solvent is generally 1:0.8 ~ 1 ratio, that is, borax 30 ~ 40%, nitrate 25%, quartz sand 15 ~ 20%, fluorite 5 ~ 10%, the other for the soda, manganese oxide, etc.. In the furnace temperature of 1000 ~ 1100 ℃ for about 3 hours of melting and slag removal, can be obtained with gold and silver for more than 85% of the gold ingot (synthetic gold).