The Burning Property Of White Cement Raw Material And Its Application In The Predecomposition Kiln

Facing the contradiction which the domestic white cement industry technology isn’t satisfied with the increasing domestic needs for high-quality white cement, the domestic white cement industry need the technology innovation urgently, it is the key for resolving the contradiction to apply the predecomposition kiln in white cement production. The adaptability and design optimization of white cement predecomposition kiln was explored by combining laboratory research and the white cement predecomposition kiln production line design in this paper.The burnability of white cement raw material was studied by the burnability test and the comprehensive thermal analysis, the results showed that:①The increasing of KH and SM will make the white cement raw material burnability worse, the KH of white cement predecomposition kiln could be controlled over0.92, the SM of white cement predecomposition kiln could be controlled at5or higher.②The predecomposition characteristics of white cement raw material and ordinary cement raw material are basically identical, the predecomposition of them is divided into to two stages,which are water evaporation and carbonate decomposition, the white cement raw material decomposition heat consumption is1269kJ/kg.cl, the ordinary cement raw material decomposition heat consumption is1382kJ/kg.cl, the decomposition of CaCO3in the white cement raw material and the ordinary cement raw material is in according with the shrinking cylinder mechanism with surface reaction rate controlling, the activation energy of CaCO3in the white cement raw material is219kJ/mol, the activation energy of CaCO3in the ordinary cement raw material is233kJ/mol, thus, the predecomposition characteristics of them are basically identical, which is theoretical basis for applying the predecomposition kiln in white cement production.According the mature design parameters of the ordinary cement predecomposition kiln, aiming at the features of white cement predecomposition kiln, this paper came to some optimal design measures as follows:①The white cement predecomposition kiln could get secondary air and tertiary air by adding the heat exchanger behind the kiln tail.②Through strengthening the sealing of the kiln system to reduce system air leakage, taking anti-material accumulation design, using anti-crust refractory at some parts which blocke and crust easily, the probability of block and crust will be reduced.③The white cement predecomposition kiln could reduce system heat loss by increasing the refractory thickness.According the analysis of HBJY white cement predecomposition kiln trial production, the HBJY white cement predecomposition kiln production line should optimize it by three aspects as follows:①The raw material quality must be controlled strictly, it is the key to reduce the Fe2O3content of raw for white cement raw material quality, on the other hand, the appropriate alkali content of raw material which can reduce the probability of block and crust, improve the burnability of white cement raw material should be explored.②The coal quality control should be enhanced, except the basic indicators to meet the production, the internal water content of coal must be controlled under1%, the coal fineness must be controlled under4%(80μm sieve residue), the coal complete combustion in the calciner should be ensured.③Based on the premise which the white cement predecomposition kiln can produce stably, the possibility of using fluorite in the white cement predecomposition kiln and the appropriate added fluorite content should be studied cautiously to avoid the block and crust accident.The actual output of HBJY predecomposition kiln white cement clinker production line is more than380t/d, the heat consumption of white cement clinker is about5442kJ/kg.cl (1301kcal/kg.cl), the whiteness of white cement clinker is about85degree, HBJY predecomposition kiln white cement clinker production line has achieved all design targets.