Research And Design Of Bath Smelting Process Of Hot Acid Leaching Residue For Zinc Hydrometallurgy

Conventional leaching and hot acid leaching are the mainstream processes used in wet zinc smelting.The leaching residue(lead-silver residue)and Jarosite residue produced by the hot acid leaching process are commonly used in the form of stockpiles.The fire treatment technology of wet zinc leaching residue has obvious advantages in environmental protection and economy.The technology of rotary kiln and fuming furnace is high in energy consumption,secondary pollution or comprehensive recovery effect;while flash smelting and Ausmelt have high investment and complicated operation.It is necessary to develop a leaching residue treatment process with high efficiency,low energy consumption,good environmental protection comprehensive utilization and low investment.Based on the literature and the practice of molten bath smelting industry,this paper analyzes,researches and designs the process of comprehensive utilization and harmless treatment for the 250,000 t/a hot acid leaching residue using oxygen-enriched side blowing bath smelting combined with fuming method.(1)The phase and composition of lead-silver residue and jarosite residue were analyzed by X-ray diffraction and fluorescence spectroscopy.The feasibility of leaching residue from molten bath smelting was theoretically analyzed.The technical route was preliminarily determined.(2)Tested the moisture content and melting point of the leaching residue.Leaching residue moisture content 33.6%.The melting points of jarosite residue and lead-silver residue are 1446?and 1052?.Mixed residue(jarosite residue:lead-silver residue=2:1)melting point is 1141?.The molten residue type at 1250?adopts mixed residue:Ca O/Si O₂=0.5,Fe/Si O₂=1.5,mixed residue viscosity is less than 0.5(Pa·S),and the fluidity is good,which can realize the separation of dross in the molten pool melting process.(3)The effects of coke leaching residue ratio,melting temperature and time on the volatilization rate of Pb and Zn were investigated by single factor test.The results showed that under the conditions of carbon content/slag=1/6,melting temperature1250°C and melting time 60 min.The smelting residue contains Pb0.626%,Zn5.599%,and the volatilization rates of Pb and Zn are 91.73%and 20.26%.(4)The smelting process parameters were determined through relevant literature,laboratory tests,and 9m²side blow furnace industrial test.The bed energy rate can reach45?55t/m²·d and the coal consumption is 15?25%.Under the condition of Ca O/Si O₂=0.5 and Fe/Si O₂=1.5,the treated residue contains Pb 0.58%,Zn7.0%,and smelting flue gas:The SO₂concentration was 3.1%.It shows that the molten bath smelting can achieve effective melting of leaching residue and separation of Pb and Zn.The concentration of flue gas meets the basic requirements of acid production and achieves the intended purpose of slag.(5)Based on the objective requirements of industrialization of 250000t/a zinc leaching residue treatment,this paper has carried out preliminary design on the process of fuming furnace combined bath smelting process of oxygen-rich side blowing.(a)The metal balance and fuel consumption utilization levels of the bath smelting and fuming furnace process were analyzed by metallurgy and heat balance calculation.The design of the oxygen-enriched side blowing furnace and the fuming furnace was completed.The oxygen-enriched side blowing melting furnace adopts a rectangular furnace type and a three-layer cooling water jacket maintenance structure;the fuming furnace uses three conventional three-layer water jacket cooling structure furnace type.(b)Completed the selection and design of related auxiliary equipment.Make sure to use a steam pipe to indirectly heat the drum dryer;determine the specifications of the electrostatic precipitator,bag filter and waste heat boiler.(c)The analysis and design of the process environmental protection measures were carried out;the economic analysis of the residue treatment project was completed;the key equipment structural design and the general layout drawing were completed.The research results of this thesis have important reference value for the enterprise's oxygen-enriched side blowing smelting technology to treat zinc leaching residue project.The relevant design results have been adopted in the leaching slag treatment industrialization project.