Effect Of Lead-zinc Tailing On Formation And Properties Of Portland Cement Clinker

Lead-zinc tailing is solid waste produced in the mining process of lead-zinc mines.A large number of tailing are stored in tailing reservoirs or natural areas,which brings serious environmental risks and potential safety hazards to the surrounding environment.The chemical composition of lead-zinc tailing is close to that of aluminium and siliceous raw materials.The rich trace elements in lead-zinc tailing can also play a part of mineralization in the process of cement clinker calcination.The application of lead-zinc tailing in the preparation of cement clinker conforms to the concept of solid waste reduction,harmlessness and resource utilization.In this paper,taking lead-zinc tailing as the object,combined with actual production,the sintering process and mineral composition of cement clinker with different tailing content were studied,and the most suitable tailing content in the process of calcining cement clinker with lead-zinc tailing was explored.At the same time,under laboratory simulation conditions,the effects of heavy metal oxides such as PbO,ZnO and SnO₂ on clinker quality were studied,which provided theoretical support for the preparation of cement clinker with lead-zinc tailing as raw cementIn this paper,the doping of lead-zinc tailing can promote the formation of C₃S in clinker.The optimum amount of tailing is 3% in the raw clinker which turns out that the content of C₃S and the M1-form C₃S in clinker takes over the most,and the quality of clinker comes out the best.Lead and ziinc in tailing are beneficial to the formation of C₃S in clinker,while SnO₂ is not conducive to the formation of C₃S in clinker.SnO₂ inhibits both M1 and M3 form of C₃S.With the increase of PbO and ZnO content,C₃S crystalline phase transforms from M3 to Ml.The addition of PbO and ZnO can enhance the strength of clinker.The results of laboratory research are applied to production practice.It is found that increasing the saturated lime ratio KH can effectively increase the content of C₃S in cement clinker.In the pilot test,increasing the saturated lime ratio can improve the 28-day compressive strength of cement clinker,which can reach about 60 MPa.