The Detoxification Of Tailings Slurry Containing Cyanide Of Liaoning Wu Long Gold Mine

The quantity of gold mine tailings in China is particularly alarming and the number of the tailings which contain cyanide can reached 24.5 million tons every year. As the technical difficulty of extracting relatively large, low-tailing has been difficult to be taken good use. A lot of mine tailings have formed an important factor to constrain the continual development of mine and endanger the ecological environment around the mining area. In this paper, we will research the tailing slurry containing cyanide of Liaoning Wulong gold mine, aiming at finding a plan which is suitable and reasonable to disposal the tailing.The methods to disposal cyanide are many, but only chlorine-oxidation, acidizing recovery method, complex precipitation method and sulfide oxidation can be used in practice. The concentration of cyanide in Wulong gold mine tailings is 250-300mg/L, not too high, and after consulting to the lead of the mine and domestic and foreign literature, the alkaline chlorine-oxidation is chosen to disposal the tailings finally.After the treatment of simulating cyanide waste water, we compared bleaching powder with calcium hypochlorite and found out which is better. When the cyanide concentration of waste water is around 230mg/L and the emission concentration must below 0.5mg/L, the necessary amount of bleaching powder is 14kg/t (wastewater), while the necessary amount of calcium hypochlorite is 6.8kg/t (wastewater). At last, the calcium hypochlorite is selected to be the most proper oxidant.Through the direct disposal of tailings found that when the concentration of cyanide in the tailings is 250-300mg/L, the best conditions to enable the leaching concentration of the tailings to fill the final requirements of lmg/L is that the calcium hypochlorite 8.50 kg/t (tailing), stirring time 5 min, stirring intensity 300 r/m, pH the original 9, stay time after stirring 25 minutes. After calculating the cost of the tailings, it is too high to disposal the tailings without any pretreatment, so the washing step is added before dealing. Experiments researched different water consumption and dosage of drugs, combined with economic analysis. The best condition is the final washing water,250 kg/t (tailing), and dosage for 0.29 kg/t (tailing). After washing the raw material cost was cut to 2.19yuan from 45.9yuan/ton slurry which treated directly.Adopting the process referred in this paper, the wastewater concentrated from tailings which containing cyanide can be used to recycle instead of emission; the tailings after detoxification treatment can meet the requirements of filling, which can reduce the importation of tailings and extend the length of service of tailings pond, with good economic returns, social benefits and environmental benefits.