强化硫化铅精矿烧结焙烧技术及机理研究

【作者】 付刚华；

【导师】 姜涛；

【作者基本信息】 中南大学 ， 矿物加工工程， 2003， 硕士

【摘要】 硫化铅精矿烧结焙烧是火法炼铅工艺的主要工序之一，铅烧结块质量的好坏将直接影响鼓风炉还原熔炼过程和铅的回收率。 针对目前硫化铅精矿带式烧结机鼓风烧结工艺中所存在的烧结料层透气性差，烧结结块率低、强度差，脱硫效果差等问题，本文以株洲冶炼厂铅精矿为对象，系统研究了硫化铅精矿烧结焙烧的强化技术。 研究表明：通过采用添加剂、强化混合料制粒、热风烧结等技术，以及对烧结机鼓风烧结工艺参数进行优化等措施，可显著改善烧结料层的透气性，强化混合料的烧结焙烧和脱硫，提高烧结结块率和铅烧结块的强度。 当烧结原料配比为返矿65％、圆盘铅10％、浸出渣7％、黄铁矿烧渣4％、石灰石3.8％、宝山铅14％，原料含硫6.0％左右、含铅45.7％左右，并添加0.5％F粘结剂的条件下，进行鼓风烧结焙烧。具体烧结焙烧工艺条件：返矿润湿水分4.0％，混合料水分6.8％，混合时间2min，制粒时间2min，烧结料层高度365mm，烧结鼓风风压4000Pa。在此条件下，可使烧结焙烧脱硫率由60.86％提高到73.73％～76.16％，成品烧结块含硫量由2.15％下降到1.51％～1.64％，ISO转鼓强度由49.93％提高到54.79％～55.44％，烧结利用系数由16.70t／（d·m²）提高到18.00t／（d·m²）～20.00t／（d·m²）的优良结果。 机理研究表明：理想的制粒效果是形成以返矿为核心，以细粒精矿的粘附料的制粒小球结构模型。粘结剂可改善矿粒表面亲水性并在矿粒表面吸附，促进了制粒小球结构模型的形成。提高料层透气性可提高氧气的内扩散速率，而白云石添加剂可提高液相形成温度，延长脱硫时间，提高脱硫反应温度。 物相组成和显微结构分析表明：采取强化措施后，铅烧结块中各物相之间的粘结明显加强，孔隙率减小，结构变得致密，显微强度获得明显改善。烧结块中钙镁橄榄石、镁铁橄榄石等含镁化合物的生成数量增多，游离CaO和SiO₂的数量减少，烧结块自然粉化率降低，质量获得明显改善。更多还原

【Abstract】 The sintering of lead sulphide concentrate is one of the most important procedures in lead extraction by pyrometallurgy. The qualities of lead sinter present important effects on the reduction smelting and the recovery of lead.In the paper, focusing on the problems existing the updraught sintering of lead concentrate, such as low bed permeability, low productivity and low qualities of product lead sinter and desulphurization, the enforcing sintering techniques were systematically investigated by using lead concentrate from Zhuzhou metallurgy plant.It was found that the improvement of permeability of the bed, qualities of lead sinter and desulphurization could be achieved by using additive, strengthening granulating, hot blast firing and adjusting the parameters for sintering.For a mixed feed of 65% return, 10% mixed lead concentrate, 7% leaching residue, 4% pyrite residue, 3.8% limestone and 14% Baoshan lead concentrate and 0.5% F-additive, the improvement of desulphurization from 60.86% to 73.37%~76.16%, the reduction of sulphur content in product lead sinter from 2.15% to 1.51%~1.64%, the increase of ISO tumbler index from 49.93% to 54.79%~55.44% and production coefficient from 16.70t/(d.m2) to 18.00 t/(d.m2)~20.00 t/(d.m2) were obtained under conditions of 4.0% moisture of return, 6.8% moisture of blend, 2min blend time, 2min granulating time, 365mm height of sinterbed and 4000Pa updraught pressure.Effective granulation is the formation of granular structure with return as core and concentrate fines as adhering layer. Binders contribute to improvement of surface waterability of returns and fines, and to linkage of fines by adsorbing on surface of fines and returns. High permeability helps to increase oxygen diffusion rate through inner pores, and dolomite acts as additive elevating fluid formation temperature, which results in longer time of desulfurization process. Therefore, desulfurization is enhanced by effective granular structure, high permeability, and dolomite as additive.Mineralogy composition and microstructure of product lead sinterwere studied. It was shown that the strengthening techniques result in increase in cohesion among components in lead sinter and decrease in porosity as well as improvement of microstructure strength. Furthermore, more compounds containing Mg, such as Ca-Fe olivine and Mg-Fe olivine are formed and free CaO and SiO2 are decreased. Therefore, the degradation index of lead sinter is decreased and the qualities are increased remarkably by the strengthening techniques.更多还原