Study On The Application Of Bauxite Tailings In Cement Production

This paper we use the bauxite tailings as a research object, respectively as raw materials for production the belite sulphoaluminate cement clinker and belite sulphoaluminate cement clinker and the corresponding sulfur aluminum acid calcium mineral additives and aluminum acid calcium mineral additives witch composed with different mineral content; Studied on the hydration and physics performance of the two kinds of cement; Studied on the hydration and physical properties and mechanical properties of ordinary portland cement witch added by sulfur aluminate and silicate mineral additives; Studied on the influence to cement and concrete basic properties when use bauxite tailings as cement admixture and concrete admixture. And use the means of XRD, SEM, polarizing microscope analysis, chemical analysis, compressive strength test and other analysis methods to explore the relevant performance and mechanism, and discussed its application value.The results indicated that, using the bauxite tailings as ingredients, when under the condition of 1300 degrees and Calcination for 50 minutes, it can be synthesized the sulfur aluminum acid calcium clinker mineral additives that mainly contains C₄A₃???,C₄AF, C₂ S mineral and the aluminum acid calcium clinker mineral additives that mainly contains CA, C₁₂A₇ and C₂ S mineral. The formation of clinker mineral is good, almost no f-CaO, and at this time the mineral burn well, with the design of CA content increased in clinker additives and the C₂ S content decreased, the amount of CA mineral formation increased.Using the fired clinker additives and adding with amount of gypsum, than produce the belite sulphoaluminate cement and belite aluminate cement after grinding system. With the content of C₄A₃??? and CA increased in clinker, the belite sulphoaluminate cement and belite aluminate cement will present that the setting time is shortened and early strength increased. But when the content of C₄A₃??? more than 30%, it will lead to a lower cement strength.Using the belite sulphoaluminate and aluminate clinker as additives added in the amount of Portland cement, can effectively shorten the setting time of ordinary portland cement and the early strength improved significantly. As the content of sulphoaluminate and aluminate mineral additive increasing, the effect of performance improvement remarkably enhanced.Bauxite tailings used as cement admixture directly, lead to a longer cement setting time,lower intensity; Using the bauxite tailings that calcined under 800 degree with the two condition of oxidation and reduction atmosphere as cement admixture, the cement setting time is shortened, strength increased significantly and slightly lower than slag powder cement but greater than fly ash cement. Treated under reducing atmosphere processing, the color of tail slag cement present to gray green, and treated under oxidizing atmosphere the tail slag cement performance as dark red color. As an admixture of concrete, it behaved a large slump loss of concrete, but the strength of concrete is superior.