The Comprehensive Recovery Processes Of Gold, Silver, Nickel, Cobalt And Copper From Tailings Of Vanadium Titano-magnetite Ore

Vanadium titano-magnetite ore reserves are widely distributed throughout China. This ore is a kind of paragenetic association of many minerals, and the value of these elements is considered to be valuable. Presently, the implementation of a comprehensive technology for the recovery of iron, vanadium, and titanium from vanadium titano-magnetite is found to be important. However, there is only few researches focus on the recovery of associate valuable minerals from this ore.The tailings of vanadium titano-magnetite used during this investigation were obtained from Shanxi province. From this sample, comprehensive recovery of low-grade precious metals such as gold and silver, as well as the recovery of non-ferrous metals, namely nickel,cobalt and copper have been investigated. In order to achieve our objectives, three methods were carried out: Direct alkaline leaching process, flotation-alkaline leaching process, and flotation-acid-alkaline leaching process. In addition, an economic evaluation of each process has been also studied.The results of the direct alkaline leaching of vanadium titano-magnetite tailings showed that the optimum conditions of the experiment were at room temperature, 11 for ammonium solution pH value, 2 ml/g for solid to liquid ratio, 1 kg/t for “cicada” leaching reagent,reaction time of 24 h. Under these conditions Au, Ag, Ni, Co and Cu leaching efficiency reached 80.1%, 74.6%, 59.7%, 57.3% and 84.2%, respectively.The flotation experiment showed that the optimum conditions of the bulk flotation test were particle size of-0.074 mm 84.5%, 25% for pulp density, 1000 g/t for Na2CO3, butyl xanthate 75 g/t, ammonium butyl aerofloat 50 g/t, SN-9#400 g/t, terpenic oil 50 g/t. Under these conditions the yield of the mixed concentrate was 3.5%, and the grade of Au, Ag, Ni, Co and Cu were 1.69 g/t, 7.3 g/t, 0.22%, 0.18%, 0.12%, respectively。The results of the alka leaching of the mixed concentrate showed that the optimum conditions of the experiment were at room temperature, 1 kg/t for leaching agent, reaction time of 24 h, stirring speed of 400 r/min, 2 ml/g for liquid to solid ratio. Under these conditions Au, Ag, Ni, Co and Cu leaching efficiency reached 96.5%, 92.3%, 90.8%, 88.7%and 97.4%, respectively.The results of the acid-alkaline leaching of the mixed concentrate showed that the optimum conditions of the experiment should be kept as below.Acid leaching step: Sulfuric acid ratio to ore 40%(g/g), sodium chlorate ratio to ore 3%(g/g), liquid to solid ratio 2 ml/g, stirring speed of 400 r/min, reaction time of 8h. Under these conditions Ni, Co and Cu leaching efficiency reached 92.8%, 91.1%, and 93.6%, respectively.Alka leaching step: Temperature 25 oC, 0.8 kg/t for leaching agent, stirring speed of 400r/min, and reaction time of 24 h. Under these conditions Au and Ag leaching efficiency reached 95.7% and 92.2%, respectively.Among the three methods used for treatment of vanadium titano-magnetite tailings, it is found that under the optimum conditions of flotation followed by alkaline leaching, the processing of 20 000 tons of tailings per day will bring a daily operating profit of 513 338 RMB.