The return of cyanide-lean liquid is a direct method of recovering cyanide. In the early literature, it was considered that the lean liquid in the cyanide plant could not be returned directly. The practice of modern cyanidation has corrected this misconception. Nowadays, cyanide plants at home and abroad have returned cyanide-depleted liquid directly to the operation process instead of adding water (or returning to the ball mill grinding process), which makes it easier to achieve solution balance and reduce cyanide in cyanide plants. Consumption. Only a portion of the excess liquid is treated and discharged. The cyanide solution of a mine in China is directly returned to the preparation of cyanide solution without being replaced by a zinc wire, and the effect is good. The practice of the mine proves that the concentration of Cu 2 + , Zn 2 + and S - ions in the solution increases after the cyanide solution is returned to use, but there is no accumulation phenomenon; the dissolution rate of gold starts slightly. Slower, but after 12 hours of leaching, the dissolution rate before the return of the lean liquid is reached. Zhang Fengge conducted a theoretical analysis and practice verification of the cyanide lean liquid return process. He pointed out that in the cyanidation system, the sodium ion concentration can fully characterize other impurity components (mainly a variety of anions paired with sodium ions, such as CN - , OH - , Me(CN) n m - , CNS - etc.) The macro sum, the concentration of any impurity component in the system is never more than the concentration of sodium ions. In any continuous cyanide plant that uses the lean liquid return process, sodium cyanide (ie, sodium ions) is added to the cyanide tank again and again, and it is also required to be carried out in the bottom liquid phase of the three-layer concentrator. Take the sodium ion. As the number of lean liquid returns increases, the concentration of sodium ions in the cyanide leaching tank and the circulating liquid phase will increase accordingly. At the same time, the amount of sodium ions carried away from the bottom liquid phase of the three-layer concentrator also increases. After the number of lean liquid returns reaches a certain minimum value, the amount of sodium ions carried away from the bottom liquid phase of the three-layer concentrator is exactly equal to the amount of sodium ions added to the next cyanide leaching tank. At this time, the balance of sodium ions is achieved for the entire cyanide system. In this way, the impurity components will never increase again in the liquid phase of the entire cyanide system. This laid the theoretical foundation for the application of the lean liquid return process. This balance occurs only after the lean liquid returns 4 to 5 times, and the accumulation of impurity ions and sodium ions in the system cannot be infinitely increased. Therefore, the lean liquid return process can be realized only by purifying the adhered water brought out by the bottom stream of the three-layer concentrator, and the amount of water to be purified only accounts for less than 1/3 of the lean liquid returning process, which can save production water 2 ∕3 is an economic and reasonable gold extraction process. And from the production practice of some lean liquids returning to the cyanide plant, whether it is the high-concentration NaCN (7kg of tons of mine) leaching of the North Gold Mine, the medium concentration of NaCN (ton of mine 2.5kg) leached Luoshan gold mine and low concentration The two chemical plants leached by NaCN (ton of calcined 0.8kg) have been running for one to several years, the production is normal, and the gold leaching rate is stable. In foreign countries, the application of lean liquid return process is also very extensive. For example, the Carrolline Gold Mine in Canada is to return the clarified cyanide-depleted liquid exuded from the tailings instead of adding water. Automatic Sewing Machine,Bag Sewing Machine,Folding Sewing Machine,Sewing Stitching Machine ZHEJIANG LIANKE MACHINERY CO.,LTD , https://www.zjlinkmachinery.com