| Coal consumption is a major part of China’s energy consumption structure. Solid waste gangue are generated from the coal mining progress, the excessive emissions and simple disposal of gangue lead to the environmental, social and economic problems.with the rapid economic and social development, the problem about resources, energy, environment is increasingly outstanding,gangue comprehensive utilization attract more and more attention. At the same time, the traditional cement clinker for the preparation of the cement industry faces grave situation that high-quality high-calcium limestone resources are depleted. Preparation of traditional cement clinker raw material selection is more stringent. The requirement of gangue chemical composition and quality of the limestone resources are higher, the preparation of ordinary portland and sulfur aluminate cement clinker use gangue facing technology, resources and other issues. Because of the problem generated in the Gangue utilization process and the problem of the shortage of high-quality calcium raw materials in cement industry, the subject put forward the study of eco-cement key technology of the preparation of Q phase cement which use gangue and low-quality calcium matrix. The study strive to efficient use of heat and slag of gangue and resoure utilization of low-quality calcium matrix in the cement industryChemical composition analysis, melting characteristics analysis and heat value analysis was carried on gangue and paper mill sludge, From the chemical composition analysis results of Gangue and paper mill sludge, We can clearly see, the chemical composition of the gangue is similar to the clayey materials used in the cement production. the content of Si and Al is high.It is entirely possible to use gangue in place of the clayey material in the cement industry. CaO content in the paper mill sludge is not high, but it is enough to meet the requested content of CaO of Q phase cement. From the melting characteristics analysis results of Gangue and paper mill sludge, We can clearly see, the ash melting point of gangue is a bit high(above1500℃),but is lower than clay (melting point1580℃). And the ash melting point of paper mill sludge is a low. If the melting point of raw materials is reduced. it will play a positive role during calcination of the raw material, If the melting point of raw materials is reduced,the temperature of liquid appear will be lower and contributing to the firing of clinker, reducing the firing temperature. In addition, From the heat value analysis results of Gangue and paper mill sludge, We can clearly see that gangue and paper mill sludge itself has a certain amount of heat, which can also provide some heat for cement calcining,So as to achieve the purpose of saving cement calcining coal consumption.Gangue,low-grade calcium matrix sludge,analytical pure MgO, analytical pure CaO and analytical pure SiO2were selected as experimental materials. According to the molecular formula of the major minerals of the mineral composition of the Q phase cement (6CaO·4Al2O3·MgO·SiO2), the proportional programme of raw material of the Q phase cement were designed and calculated.There are three designed proportional programme:(1) Analytical pure MgO, analytical pure CaO and analytical pure SiO2were selected as experimental materials, the fundamental proportional programme of the Q phase cement raw material was designed.(2) Gangue,Analytical pure MgO and analytical pure CaO were selected as experimental materials. According to the fundamental proportional programme of the Q phase cement raw material, the proportional programme of raw material of the Q phase cement calcined by gangue was designed.(3) Gangue, low-grade calcium matrix sludge, and analytical pure CaO were selected as experimental materials. According to the proportional programme of raw material of the Q phase cement calcined by gangue, the proportional programme of raw material of the Q phase cement calcined by gangue and low-grade calcium matrix sludge was designed.Test simulates cement calcining process by High temperature resistance furnace. P repar the raw material according to the proportional programme of raw material of t he Q phase cement,and then grinding, homogenization and calcination were carried on the raw material. The test was set five calcination temperature1,200℃,1230℃1260℃,1290℃,1320℃. The raw material were calcinated,and XRD analysis was carried on the clinker samples of the calcined test. The experimental results sho wed that when the temperature reached1320℃, large quantity of liquid phase appear ed and the color of the clinker became darker. According to the XRD analysis, the result show that the main mineral composition of the cement clinker were2CaO·SiO2and Q phase.they both have good hydration properties.At last analysis of sulfur fixation characteristics was carrired out on the Q phase cement clinker, The result show that the effect of sulfur fixation of the quaternary phase cement clinker calcinated by gangue and low-grade calcium matrix or the quaternary phase cement clinker calcinated only by gangue under1320℃are both very good, which are up to50%. The Sulfur fixation rate of the former is71.13%and the latter is50.24%. |
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