| Gold, as a strategic metal of our country, plays an irreplaceable part in the national economy and social development. However, the development of gold industry has always been slowed down, due to the poor extraction technology from the gold concentrate which contains copper, lead, zinc, arsenic, carbon, and so on. Dealing with complex unwieldiness gold concentrate is an inevitable course from all angles, for instance, the development history of world’s gold industry or the amount of gold holdings. This thesis studied the melting technology of intractable gold concentrate in detail, on the basis of the existing achievement of gold and non-ferrous metal smelting, and develop the process of oxygen-enriched bottom-blown smelting technology and dry bag process for arsenic collection in detail. The results of this research are as followed:The proportion of charges in the melting process was calculated according to the composition of raw materials. And the amount of quartz required was 5.32%, matte productivity was 28.62%, slag yield was 48.77%, the ratio of oxygen to furnace burden was 172.39, while that of oxygen-enriched air needed 14561.1Nm3 per hour. Through single factor test we can determine the optimized technological conditions that Cu, Fe, Zn, Pb, Au and Ag content of matte were accounted for 45.37%,23.23%,1.17%,1.73%, 79g/t and 2119g/t, respectively. The smelting slag was composed of matte, magnetite, fayalite, and vitreous phase. Because Au and Ag in the slag mainly lied in matte and its Cu, Ag and Au content were less than 3.27%,170g/t and 3g/t, respectively, so that Cu content of slag needs to reduce. Cu existed in the mushroom head was constituted of matte and CU2S, whose contents were 31.8% and 10.1%, respectively. The form of Fe in the mushroom head was Fe3O4, when the amount of the lump coal and calcium oxide were 0.6t/h and 2.5% and Fe/SiO2 was 1.73.From experimental studies of of the slag dilution process, We made a final determination by using a method of slow cooling-grinding-flotation to deal with slag. the operation conditions were as followed:the cooling rate was controlled at 1 ℃/min, from 1250℃ natural cooling to 1000℃, then completely cooled by water, and the grinding fineness rate was 90% lower than 0.074mm, slurry density was 40%, the dosage of collector was 120g/t, the dosage of 2#oil was 1OOg/t under the conditions, the copper concentrate grade and recovery were 21.38% and 94.5% respectively, the copper concentrate enriched approximately 7.8-fold, gold and silver enrichment were about 4.5 and 5.1 times, respectively. The metal contents of tailing would be very low, and Cu, Au and Ag content of tailing were accounted for 0.20%,0.2g/t and 9.4g/t respectively.From the analysis of the physical and chemical properties of arsenic trioxide, it can be learned that the content of arsenic trioxide in the gas varies at different temperature. And the paper has used the method of rapid temperature changes so that arsenic trioxide crystallized to become solid, so as to achieve the separation and recovery of arsenic. The research shows that the arsenic removal process should ensure that the temperature of flue gas entering tower was below 350℃ while the outlet temperature was lower than 150℃. We used specification of the quench tower,(?)4500x 14700mm, according to the gas velocity and pace times, controling water quantities of the quench tower with 5.2t/h, the spray gun average atomized particles were 80-120μm in diameter, assure that arsenide in the gaseous phase of flue gas to break quickly through temperature zone of forming vitreum arsenide at the residence times of flue gas in the quench tower,99% AS2O3 was collected by bag type dust collector.In accordance with the practice of two years production, feed methods, the holes of slag and copper shed of the oxygen-rich bottom blowing smelting furnace had been optimized in order to improve the safety factor, reducing the labor intensity, optimizing separation of matte and slag. We designed uniform section and slot type dual casing oxygen lances, gas supplying capacity of single oxygen lance can reach 1800Nm3 per hour. By controlling the flow of oxygen lance and pressure of bottom blowing promoted gas to erupt in jet way and spearhead of oxygen lance to develop loose mushroom head, which can effectively protect oxygen lance and refractory brick, and extend life of oxygen lance to 3600 hours, the bed-capacity of bottom blowing smelting furnace can reach 18.82t/m3·d, improve working rate of bottom blowing smelting furnace. The average corrosion speed of oxygen lance was 0.02-0.03mm/h by actual measurement.The research results show that the oxygen-rich bottom blown bath smelting furnace was not strict with raw material requirements and able to handle the complexity of gold concentrates, which has a high trapping rate of precious metals. Without coal exists, the oxygen-rich bottom blowing smelting furnace can also achieve self-heating melting and almost no carbon emissions, while reducing energy consumption, realizing low-carbon economy. The oxygen-rich bottom blowing smelting furnace is capable of producing different Fe/SiO2 slag according to different raw materials, and does not produce the foamy slag, which reducing the wastage of copper and precious metals in slag. The reasonable structure of the oxygen gun and the mushroom head control technology can extend the life of oxygen lance and refractory brick. |
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