基于水泥窑协同处理石灰干化污泥工艺研究磷、硫对碳酸钙分解的影响

Effect of phosphorus and sulfur on calcium carbonate Decomposition in Cement Kiln Co-processing lime-dried sludge

针对水泥窑协同处理石灰干化污泥工艺,利用热差分析仪、X射线衍射和扫描电子显微镜分别从碳酸钙分解热力学和碳酸钙微观演变的角度研究了不同量的磷和硫掺比对碳酸钙分解的影响规律.实验结果表明,在碳酸钙烧制中,掺加0.5%的磷(以磷酸钙计)和硫(以硫酸钙计),使碳酸钙表观分解能分别降低了7.35%和8.04%,峰值温度分别降低了70.82℃和59.32℃,有效促进碳酸钙的分解;对其促进机理研究发现,硫酸钙、磷酸钙及其分解产物焦磷酸钙自身并不与碳酸钙及其分解产物氧化钙发生反应,他们仅破坏了碳酸钙的表面结构,促进了二氧化碳的释放,从而利于的碳酸钙分解.本研究结果表明,掺加一定量的石灰干化污泥引入磷和硫,利于水泥熟料的烧成.

The effects of phosphorus and sulfur on the calcium carbonate decomposition during the treatment process of lime-dried sludge in cement kiln were studied from the aspect of thermodynamics and microscopic evolution of calcium carbonate decomposition using scanning electron microscopy（ SEM）,thermal diffusivity analysis and X-ray diffraction. The experimental results showed that the addition of 0.5% phosphorus（ calculated as calcium phosphate） and sulfur（ calculated as calcium sulfate） reduced the apparent decomposition of calcium carbonate by 7. 35% and 8. 04%,the corresponding peak temperature was reduced by 70. 82 ℃ and 59. 32 ℃,respectively,which effectively promoted the decomposition of calcium carbonate. The analysis of its promotion mechanismshowed that calcium sulfate, calcium phosphate and its decomposition products calcium pyrophosphate did not react with calcium carbonate or its decomposition product calcium oxide. They only undermined the surface structure of calcium carbonate and promoted the release of carbon dioxide,which was conducive to the decomposition of calcium carbonate. The results of this study indicated that the incorporation of a certain amount of lime-dried sludge is conducive to the firing of cement clinker by introducing the phosphorus and sulfur.