Influence factors of TG-DTG method to test the combustion characteristic of refuse derived fuel (RDF) for the cement kiln was studied; the relationship between the proximate analysis and the combustion characteristic parameters of RDF was discussed. The combustion characteristic parameters were taken as a combustion process evaluation for both RDF and coal, and their influence on thermal parameters of the cement kiln system was discussed. The research results showed that for RDF combustion characteristic TG-DTG test, the heating rate should be 20℃/min, surroundings gas oxygen concentration should be 21%, the flow rate should be 100ml/min. When ash content of the refuse derived fuel reduced, the volatile content increased, the ignition temperature would decrease, relatively the burning time extended. RDF combustion characteristic had an important influence on cement kiln operation stability, therefore cement production should cope with its sufficient combustion characteristic research, strictly control the proportion of alternative fuels, at the same time, pay close attention to the thermal parameters of kiln system.

Effect of cement properties which using a bauxite tailings as admixture was studied. The mineral composition and the particle size distribution of the bauxite tailings were analyzed. The water demand at standard consistency, setting time and compressive strength of the bauxite tailings cement were tested. The results showed that: the original bauxite tailings contain the minerals of a class of kaolinite (halloysite, nacrite, dickite), diaspore and a class of mica (muscovite, potassium mica, polylithionite). Taking the burned bauxite tailings as admixture, the cement standard consistency was higher, the setting time was shortened obviously and the compressive strengths were a little lower than which with the fine blast furnace slag but higher than the fly ash. The burned bauxite tailings and fine blastfurnace slag and fly ash compositing together as admixture, the standard consistency was apt to decrease and the compressive strength increased.

The effect of STPP on the grinding efficiency of hematite was studied and the mechanism was also analyzed in this paper by measuring the grinding pulp viscosity and the absorption characteristics. The results showed that the content of ＜0.074mm ground product was increased by 29.83% under the appropriate conditions using STPP as grinding aid. STPP reduced the pulp viscosity and prompted the particle dispersion; STPP formed physical and chemical adsorption on the hematite surface , reduced the surface hardness of the hematite.

According to my company's original clinker hammer crusher failure frequency and high maintenance costs, by limiting the production of the kiln in winter, the grate cooler clinker hammer crusher was modified. Practice shows that after the retrofit, the equipment operation is stable, the power consumption is reduced greatly, the vibration of the equipment is also reduced, the cost of the crusher maintenance is reduced greatly, the material granularity becomes smaller, the cement cab be easily ground and the cement production cost is also reduced.