Study On The Distribution Of Chlorine-alkali-sulfur And The Safety Of Heavy Metals Of Products Around Co-processing Solid Waste In The Kiln

The technology of co-processing solid waste in the kiln is the most environmentally friendly a garbage disposal method. It has both a waste incineration technology and environmentally friendly features. It not only can effectively eliminate dioxins and other acidic gases produced by waste incineration, also can dissolve the heavy metals in the waste incineration residues. However, alkali, chlorine, sulfur components of solid waste incineration has an adverse on the cement kiln operation. The cement products will have some security problems of heavy metals. So the study on the distribution of chlorine, alkali, sulfur components of the material in the preheater and the environmental safety of heavy metals of mortar not only in favor of the cement industry to better cope with chlorine, alkali, sulfur components caused 4th and 5th stage cyclone crust problems in the preheater, but also is conducive to safe application of cement products. It for the cement industry in China is of great significance to the energy conservation and emission reduction and green environmental protection.In this paper, studying on the co-processing solid waste in the cement kiln of Yellow River Tongli, using the online sampling methods and mainly to study the following aspects:1)analyze the calorific value of the solid waste and the influence of waste composition on the enrichment of chlorine, alkali, sulfur components in the system of cement kiln. 2)the distribution and change rule of chlorine, alkali, sulfur components of the material at all levels of the cyclone tube of the preheater system around the co-processing solid waste in the kiln. 3) study the influence of the physical properties of the cement clinker around the co-processing solid waste in the kiln. 4) analyze the environmental safety problems of heavy metal of clinker and bottom ash as a mixed material in cement products.The analysis results of solid waste show that the moisture content of solid waste in luoyang area is 30.71%. The low calorific value of wet base of solid waste is 5840 k J/kg and is designed for the incineration. In the current technology of the co-processing solid waste in the kiln, the vast majority of chlorine, alkali, sulfur component of solid waste is with the smoke and ash into the calciner. The incineration has a significant influence on the amount of chlorine component in the cement kiln system. Take the raw material in the Yellow River Tongli Cement(5000 t/d kiln) as example, when the chlorine component of solid waste in Luoyang converted to compound chlorine content of raw material, chlorine content of the original raw material has 29.92 percent increasing rate. The chlorine content of raw material has great impact on the safe operation of the furnace. The alkali content of clinker is about 0.7%, when the alkali content of clinker continues to increase, the cement products durability greater impact. The sulfur content of clinker is about 0.33%, the content is not high, little effect on the production of sulfur.From the distribution and variation of chlorine, alkali, sulfur components of material in the levels of cyclone preheater tube can be obtained: most of chlorine and alkali component concentration in the material of the main 4th, 5th stage cyclone, whereas the sulfur component is mainly concentrated in the material in 5th stage cyclone. After co-processing solid waste, the chlorine alkali component content of materials in 4th and 5th stage cyclone of preheater than before disposal has been a significant increase in the relative. The sulfur component content of material in 5th cylinder is the highest and more sensitive. The chlorine, alkali components by the material into the kiln system were about 40% and 20% of the residues or enriched in the kiln, and less residual or enrichment of sulfur component. In the cement kiln system, the chlorine component content of fumes, dust and clinker were low, when the chlorine content of solid waste is high or the volume of co-processing solid waste is big, the chlorine component content in the kiln will increase enrichment.The study of physical properties of clinker around the co-processing solid waste is show: the chemical composition, mineral composition and physical properties of cement clinker remain basically unchanged around the co-processing solid waste. The current solid waste disposal process conditions is describes that the volatile components of incineration of solid waste and bottom ash as raw material not affected the chemical composition, mineral composition and physical properties of clinker.The environmental security result of cement product of clinker and bottom ash as admixture showed that heavy metal leaching of cement product in the water(p H=7) and simulated acid rain( p H=3.2) can meet type Ⅱ surface water standard around the co-processing solid waste in the kiln. When in the water and simulated acid rain situation, with 10% of the bottom ash as a cement admixture of its products, the concentration of heavy metal leaching of cement product can meet type Ⅱ surface water standard, and heavy metal leaching of cement product can reached the surface impregnation dissolution typeⅠsurface water standards. It showed that the effect of heavy metals in cement solidification is good and the heavy metal environmental security performance of the prepared cement products meet the relevant requirements.The results of this study will provide a theoretical basis to the design and application of technology of co-processing solid waste in cement kiln, reduce the pressure on municipal solid waste disposal areas, but also deal with other solid waste for the dry cement kilns laid a theoretical foundation conducive to a more full disposal of solid waste in the cement industry collaborative role in the implementation of our strategy for sustainable development to contribute.