| The gold ore of a certain gold mine in Shaanxi province is defined as a low sulfur carbon-bearing refractory gold ore because the recovery is only 14.84%with a conventional cyaniding process.In order to improve the recovery,the process mineralogy is analyzed and the exploration test and optimization of process parameters were studied,then the production cost and profit of different processes were contrasted.The results of process mineralogy research show that the ore is classified to carbonaceous siliceous slate ore.The main metal minerals of it are pyrite and chalcopyrite,and the main nonmetallic mineral is quartz.The main forms of harmful carbon are organic carbon and graphite,mainly with organic carbon.The gold occurs as fine-and microfine-grained natural gold in quartz?as enclosed gold?and in the fissure of minerals.The forms of nature gold are mainly irregular,the secondly in granular,crescent,wheat grain,fine strip,kernels and triangles.And the mostly particle diameter of gold are less than 0.01mm.Exploratory tests are conducted by complete mud cyanide leaching,competitive adsorption leaching,carbon in leaching,oxidation roasting leaching,single floatation,and flotation-cyanidation.The result shows that high gold recovery can be achieved by the process of oxidation roasting leaching and flotation pre-treatment cyanidation leaching.The condition test of flotation-pretreatment-cyanide leaching process shows that a gold concentration with a grade 5.41g·t-1,yield 16.5017%and recovery 39.09%can be obtained when the grinding fineness was-200 mesh content 90%,the dosage of ammonium dibutyl dithiophosphate was 35 g·t-1 and the dosage of pine camphor oil was120g·t-1.The gold concentrate was roasted 1h at 600?,while the flotation tailings were pretreated under 225g·t-1 kerosene,the leaching rate of gold can reached 82.43%when the two products were combined leaching.The roasting of raw ore-all-slime cyanidation-carbon leaching test shows that the leaching rate of gold reached 90.7%,the adsorption rate reached 98.83%in the conditions of roasting temperature of 600?,calcination time 1h,grinding fineness of-200 mesh content 80%,sodium cyanide 500g·t-1,pulp concentration 40%,leaching time 12 h,carbon density 18g·l-1,prepreg 6 h and carbon leaching 6 h.The preliminary economic calculation of production cost,output value and profit of the three processes such as flotation-pretreatment-cyanide leaching was carried out,the result shows that the raw ore roasting-all-slime cyanidation process has the advantages of good index and low cost,and its production profit is the highest,and this process can earn more 181 RMB/t than the all-sludge cyanidation process.The study can provide theoretical guidance for the development and utilization of the refractory high carbon oxidized gold ore,and also has reference significance for the production and application of carlin type gold deposits in western china. |
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