以铅锌尾矿为原料煅烧水泥熟料

以广西河池富源铅锌选矿厂尾矿为主要原料煅烧制备水泥熟料,从不同煅烧温度下熟料成分的差异,水化产物的微观相貌和组成,煅烧过程中重金属的固化与熟料净浆试块的毒性浸出情况,以及熟料净浆试块的力学性能等方面探讨了用该铅锌尾矿制备水泥熟料的适宜工艺条件。试验结果表明:掺有35.4%广西河池富源铅锌尾矿的生料煅烧制备水泥熟料的最佳烧成温度为1 350℃,此时可生成大量有利于熟料强度的C2S和C3S。该水泥熟料的主要水化产物为C—S—H和钙矾石,试块前期强度的主要来源是钙矾石,后期强度的主要来源是C—S—H,C—S—H填满试块内部空隙,增大试块密实度,使试块28 d龄期的抗压强度达到43.68 MPa,与普通硅酸盐水泥P.O 42.5的28d抗压强度指标相当。煅烧过程中Pb的固化率较低,仅为21.16%,而As和Zn的固化率则高达87.61%和91.43%。养护龄期为3 d和28 d的水泥净浆试块浸出液中As、Pb、Zn的含量远低于浸出毒性标准。这种水泥熟料在生产地下胶结充填料的胶结剂方面具有一定潜力。

Study on Calcination Cement Clinker Using a Lead-zinc Tailings as Raw Material

Cement clinker was prepared using tailings from Fuyuan Lead-zinc Plant of Hechi,Guangxi Province,as main raw material,mechanism of cement production from lead-zinc tailings was discussed from different aspects,such as the composition difference of clinker with different calcination temperature,microscopic appearance and composition of hydration products,solidification of heavy metals during calcination,the toxic leaching of clinker test block and suitable technological conditions in parparation of cement clinker test block.Results show that the optimum sintering temperature of cement clinker calcined with 35.4％ lead-zinc tailings from Fuyuan,Hechi city,Guangxi Province,was 1 350 ℃,and lots of C2S and C3S were produced,which is beneficial for increase of clinker strength.Main hydration products of cement clinker are C-S-H and ettringite.Main reason for early strength of test block is ettringite,main reason for late strength is C-S-H.And C-S-H fill the gap within the test block,increasing the density of the test block.And its compressive strength at 28 d age was 43.68 MPa,which equal to the 28 d compressive strength index of ordinary Portland cement P.O 42.5.The heavy metals solidification of As and Zn were as high as 87.61％ and 91.43％,respectively,while the heavy metals solidification of Pb was only 21.16％.The content of As,Pb and Zn in the cement paste test block of 3 d and 28 d in curing age was much lower than that of the leaching toxicity standard.This kind of cement clinker has certain potential in production of cementing agent of underground cemented filling.