| This thesis passes to the analysis research of extracting gold mine craft of laowangzhai of zhenyuan in Yunnan in the present condition proceeds, and again and again groping and experiment in the half a year, finally establish the craft of the nitric acid pre- Oxidizing ?desulfuration ?cyaniding. Basing on NITROX method and ARSENO method, experiment pass to improve on the device of oxidation and to adopt the different reagent of desulfuration, reduced the dosage of nitric acid, and increase the nitric acid's utilization, at the same time verified different influence of different reagent of desulfuration in the craft. Although result of desulfuration of reagent AN is not as good as reagent B, characteristic of reagent A make it realize to oxidize and to desulfate at the same time through changing the method of operation. Although reagent B only can desulfate for oxidized scoria, the effect of desulfuration is obvious, which can more increase the rate of cyaniding and lixiviating. For laowangzhai gold concentrate, improvement of one percentage point of rate of lixiviating predicates enhance of benefit. Two reagents all have characteristics of simple operation and repeating usage. The accomplished concrete work of whole experiment is following.1 The thesis summarized the present condition of craft of extracting of laowangzhai, and analyzed the current existed problem. The traditional baking method produced large quantity's smoke, whose pressure of accepting dust is big. The craft still increased craft of fine grinding and alkali washing, which is complicacy. The fixed sulphur baking produce the water-soluble sulfuric acid calcium, which make against the cyaniding lixiviation. Although bio-oxidization method has advantages of high rate of lixiviation and amity environment, it exists disadvantage of long time of oxidization, the high early investment and not easily controlling operation. All is not ideal craft of extracting gold of laowangzhai.2 The thesis analyzed the reason of the difficult lixiviation according to material photograph of laowangzhai gold concentrate and after understanding traditional extracting gold craft of sulfuration mineral pre-oxidation, it fixed on the craft of the nitric acid pre- Oxidizing ?desulfuration ?cyaniding guided by the theory of the method of nitric acid pre- oxidation. That craft improved on intrinsic equipment of oxidation, designed the new system and realized circular usage of nitric acid in the reactor passing the direct conversion of N02 in the liquid of reaction to nitric acid and the liquid film to absorb the excess' s N02.3 Because the sulphur produced in craft forms twice package at gold surface, it cause low rate of lixiviation. The ARSENO method with NITROX method once adopted the method of dissolving sulfur in oxidation sediment by adding limestone the under high temperature. But this makes the flowcomplicate and have economic problem, therefore the experiment carries through research of desulfurization effect of oxidation sediment about two reagents after analysis. And discover the change of rate of cyaniding extracting gold of desulfurization sediment following the different rate of desulfurization. The effect of desulfurization is good, so the rate of cyaniding extracting gold is high , vice versa .4 Through contrasting experiment between two reagents, I analyze the different reagents to adapt different craft of extracting gold. And enlightened by the result of desulfurization of reagent A, I offer a new thinking for anode oxidization- desulfurization cyaniding craft of extracting gold. |
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