| In traditional pyro-metallurgical process,the natural oxidation slime is mixed with adjuvant materials of coal,soda and fluorite and then feed into the smelting furnace for reducing smelting, correspondingly primary slag, primary dust and lead alloy containing rich noble metals are produced.Primary slag and primary dust are sent to the Comprehensive Recovery Plant to recover the antimony,bithmuth and precious metals, while lead alloy is experienced refining process to obtain an alloy of Ag and Au excess of 97%(mass%) in the refining furnace.This process has numerous advantages of simple process,stable performance indexes and easy to realize large scale productions,which can be extensively used in treatment of lead anode slime.However,there are some drawbacks in the traditional process emerging as the production of the lead anode slime increased year by year,which needs to be improved eagerly.Moreover,the research and application of advanced equipment and new technology create right conditions for the improvement of this process.The traditional pyro-metallurgical process of lead anode slime in Henan Yuguang Gold & Lead Group CO. LTD. had many shortcomings such as long process times, low direct metals recovery,high producing cost,small treatment capacity,which had been studied and a brand-new pyrometallurgy technology of Oxygen Enriched Bottom Blowing Reduction Smelting-oxidation Refining Process has been developed.In bottom-blowing reduction smelting,antimony and arsenic were separated with noble metals by volatilizing as oxidation or entering dross,thus the primary slag, primary dust and lead alloy with high grade of gold and silver obtaining.The primary slag and primary dust were transported back to the Comprehensive Recovery Plant for further treatment,while lead alloy is experienced refining process to produce a qualified alloy.The parameters of ingredients, oxidation degree, reaction temperature, feed rate in the technology of bottom-blowing reduction smelting were easy to adjust and control,therefore a high-grade of lead alloy containing rich noble metals and the primary slag and primary dust with very low content of gold and silver were produced,which demonstrated that the speed of smelting had been improved and the capacity of equipment had been enhanced.The operation conditions and indexes in oxygen bottom-blowing reduction smelting are as follows: when temperature of 800～900℃, the feed rate of 2.0～2.5t/h, slag settling time of 1.5～2h, precipitation temperature of 850～950℃, the yield of lead alloy containing noble metals can reach to 35～45%,and that of the primary dust is 50～60% with a composition of Au<5g/t, Ag<5kg/t while yield of the primary slag is 30～40% with a component of Au<5g/t, Ag<5kg/t. The purity of oxygen is more than 99%(by volume), and correspondingly working pressure is 0.7～0.8MPa with a flow rate of 40～50Nm3/h.In industrial practice,a single converter with the model of 2540×4800 has an average daily processing amount of 25 tons of anode mud (dry weight) with 45 tons of feeding(gross weight) under the above parameters.Compared with the traditional pyrometallurgy techniques,the smelting capacity of converter with the same indicator have been improved more than two times,and the production cost in smelting-refining have declined by 609.2 yuan per ton,furthermore it can save consumption of 3.86 million per year under the prerequisite of 6000t as the smelting capacity,which bring in great economic and social benefits. |
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