1. Whole mud cyanidation of fragile ore Shenghailiena (Sint Helena) is a gold mine into production in 1951 of the old cyanide plant, due to increased ore, plant corrosion serious, obsolete equipment and gold recovery decline and other reasons, decided to build another new plant. The design of the new plant draws on the grinding practice of the old factory since 1956 and the Leslie gold mine since 1963, and the compression of production costs since the 5,000-year-old Kinross plant was put into operation in 1967. And experience as much as possible to save labor. The new plant was put into operation in September 1976, and the production scale was 300,000 tons of ore per month. The new plant has no waste rock picking and crushing operations. The ore from the mine directly enters the ore grinding machine. The grinding machine and the Krebs cyclone form a closed-circuit grinding. The whole pulp is cyanated. To improve efficiency, a few large equipments were used and sophisticated sensing and metering devices were installed. Due to the friability of the ore, the grinding is self-grinding with ore or adding a steel ball with a diameter of 100 mm. The slurry was ground to -0.074 mm (200 mesh) and cyanated in 10 flat-bottom air agitation tanks (Fig. 1). The slurry is circulated by the air lifter in the center of the mixer. In order to prevent sludge sedimentation, six high-pressure air nozzles are arranged around the riser through high-pressure air for agitation. The cap was filtered using vacuum filtration integral casting casting machine, to prevent deformation and leakage. Clarify the use of an upflow sand filter and degas with a Claude degassing tower. The precipitated gold mud is dehydrated on a horizontal belt filter and fired in a tunnel kiln. The dried zinc gold precipitate is smelted in a very large arc furnace to shorten the smelting time. The soot is collected by a bag filter. Figure 1 Flat bottom air agitation tank 1-splash cover; 2-gate valve; 3-center air riser; 4-stainless steel support pipe; 5-cone intake pipe; 6-concrete base; 7-observation hole; 8-feed trough; 9-discharge trough, 10-overflow pipe; 11-drainage pipe 2. Full mud cyanidation of fine-grained gold slate and sandstone mines The new Occidental gold mine was originally treated with cyanidation of fine-grained slate and sandstone ore. Containing ore consumes about 1% of the cyanide brass ore and 1% to 2% of pyrrhotite. The latter requires careful control of the alkalinity of the solution to reduce cyanide consumption and increase gold recovery. Although the plant has been discontinued, the process of using lead oxide to reduce the consumption of cyanide and improve the extraction rate of gold (Fig. 2) in the original operation is of practical significance. Figure 2 New Oakton Gold Mine Process The plant's original capacity to treat ore was 8,000 tons per month. The ore is broken to -9.5mm, and lime, cyanide and lead oxide are added to the two-stage closed-circuit process to 90% -0.074mm (200 mesh). The slurry concentrated by the classifier was stirred and cyanated for 30 h in 4 Defro mixers connected in series. The solution was kept to contain 0.06% NaCN and 0.007% CaO. The consumption of the medicament was NaCN 1.14 kg ∕t, CaO 1.4 kg ∕t, and PhO 300 g ∕t. The precipitate produced by cyanidation is calcined and then oxidized with an oxidant to produce a high-copper gold ingot, which is then smelted together with sulfur to remove some copper, producing 86% gold, 4% silver and base metal (mainly It is copper) 10% of the combined gold ingot. The ore contains 8.7 g of gold and the recovery of gold is 91%. 3. Hand selection and cyanidation of gold-silver quartzite ore The Kuroki gold and silver mine in Kagoshima Prefecture, Japan, and its affiliated Iwate gold deposit, mainly quartzite sulfide ore. The Chuanmuye gold and silver ore contains 7.1g∕t, silver 53g∕t, and the ratio of gold to silver is about 1:8. The two ores were first crushed by a jaw crusher to -70 mm and then washed. After removing the waste rock by hand, it was crushed in a 1.2 m cone crusher and sieved through a vibrating sieve. The sieved ore block is returned to the cone crusher and then crushed. The sieved ore is sent to the 2.4m×6m cone ball mill for grinding with the washed ore. After the grinding machine and the classifier are composed of closed loop grinding to -0.295mm (48 mesh), the classifier overflows to the Ф1.8m×4.2m tube mill and the float type classifier to form a closed-circuit grinding to -0.074mm (200 Project). The floatation type classifier overflows through a 1.8m×3.6m thickener, and then adds sodium cyanide and a small amount of lead nitrate to 8 leaching tanks (6 sets of Ф8.53m×6.7m, 1 set of Ф12.2m×3.68m). , 1 set Ф 12.7m × 5m), air and mechanical stirring leaching for 4d. The slurry was filtered through a Moor vacuum filter, and the noble liquid was precipitated in a 3 m × 9 m × 1.5 m tank to remove coarse particles, which were then filtered through a 6 m × 1.5 m sand filter. The cleaned precious liquid is deoxidized and then replaced with zinc powder to replace the precipitated gold. The precipitate is dried and smelted, and finally gold and silver are recovered by electrolysis. SHAOXING MINGQUAN TRADE CO., LTD , https://www.sxmingquan.com