Zhangjiakou gold mine was put into operation in 1970, the designed capacity of 500t / d, the original process is amalgamation + flotation, recovery rates of 75% in 1984, the transformation of gold extraction process for the CIP, dressing and smelting recovery rate More than 93%, and after several technical transformations, the production scale reached 600t/d. Table 1   Zhangjiakou Gold Mine Charcoal Factory Process Conditions [302] CIL system Prepreg time 4.1h Desorption time 18h Slurry concentration 40%~45% Desorption temperature Aeration amount 0.23m 3 / (h· m 3 ) Desorption pressure 0.31MPa pH 10.5~11.0 Desorption component 1.0% NaOH + 1.0% NaCN Sodium cyanide concentration 0.04%~0.05% Desorption flow rate 0.84L/s Charcoal immersion time 14.35h Number of cathodes in the electric storage tank 20 Activated carbon density 10~15g/h Electrogenization time 18h String charcoal speed 700kg/d Electrothermal temperature 60~90 °C Desorption electrowinning system The amount of charcoal per batch Cell voltage 1.5~3.0V Preheat time 2h Slot current intensity Pickling operation Nitric acid concentration 5.00% Regeneration atmosphere  water vapor Fossil concentration 10.00% Regeneration time 20~40min Washing time 2.0h Regeneration speed 25~35kg/h Heating regeneration Regeneration temperature One area 65 0 ° C Regeneration kiln gives charcoal moisture 40%~50% Zone 2 810 °C Recycled carbon cooling method Water quenching Three zones 810 °C Activated carbon regeneration cycle 3 months Cnc Laser Cutter Spare,Precision Laser Cutting Accessories,Cnc Laser Machine Components,Laser Cutter Consumable Parts Changzhou Cewoo Equipment Co.,Ltd , https://www.cewoocut.com
Ore nature: It is a medium-temperature hydrothermal fissure filled quartz vein type deposit. The ore is a type of sulfide-containing gold-bearing quartz vein. The main metal ore minerals limonite ore and hematite, galena and followed by white lead, lead alumina, magnetite, and a small amount of pyrite, copper ore and natural gold. Gangue minerals quartz, followed with a silk mica, feldspar, calcite, dolomite, and the like.
Most of the natural gold and metal minerals are symbiotic, among which the limonite contains gold. The ore density is 2.51 t/m 3 .
Process: After the original ore is broken by two closed-circuit processes, the particle size of the ore is -12mm. After two stages of grinding, the fineness of the ore reaches 85%-200 mesh (-0.074mm). The finely ground ore is dehydrated by a high-efficiency thickener, and the concentration of the slurry is increased to 40% to 45%, and then fed to the carbon immersion system. Cyanide is added to the carbon immersion system, filled with medium pressure air, and activated carbon is added. After two pre-dip and seven-stage soaking, the tail slag grade dropped to 0.3g/t and the tail grade dropped to 0.03g/t. The carbon leaching tailings are discharged to the sewage treatment system and treated by the alkali chloride method. After treatment, the cyanide content of the tailings slurry is reduced to less than 0.5 mg/L, and then discharged to the tailings pond for self-purification. The gold-loaded carbon sieve proposed by the carbon leaching system is washed and desorbed and accumulated in the gold recovery system. The charcoal leaching system is completed by a centrifugal carbon pump and a trough bridge. The desorption column and the electric accumulator form a closed circuit, and no noble tank or lean tank is provided. The desorption operation reduces the amount of gold contained in the activated carbon from 3,500 g/t to less than 80 g/t. The desorbed carbon is acid-washed, heated and regenerated, and then returned to the CIL system for use. Desorbing the precious liquid deposits gold in the solution on the cathode through a rectangular electrode. Gold cathode mud extracted once a month, gold and silver to the smelting chamber and smelting separation (see Figure).
Technical data: The process conditions are shown in Table 1, the process indicators are shown in Table 2, and the main material consumption is shown in Table 3. 
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