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二氧化硅对污泥烧结陶粒结构强度和孔隙率的影响
作者：秦晋一，封硕，方姣，张明慧，焦怡静，陈哲鑫
（长安大学 建筑工程学院，陕西 西安 710061）
摘要：市政污泥富含金属氧化物可以促进结晶体的形成，高温下有机质产气可以作为成孔剂，同时发热有利于内部烧结温度的提高，污泥作为原料有利于烧制陶粒。研究结果表明，烧结陶粒强度较高的化学成分配比为：SiO2 62%、Al2O3 14%、其他氧化物24%。此时陶粒强度为4.89 MPa，颗粒密度为1320 kg/m3，符合GB/T 17431.1—2010《轻集料及其试验方法 第1部分：轻集料》对800级人造轻集料的要求。试验细化了陶粒内SiO2、Al2O3及其他氧化物组分建立的三角相图。烧结的最佳温度为1050 ℃。污泥烧结中释放热量有利于高温产生流动相和小孔汇聚，但是污泥放气会对小孔汇聚产生扰动，二者之间相互抗衡，由此提出污泥陶粒烧结中孔隙和结构形成的假设。
关键词：污泥陶粒；二氧化硅；抗压强度；孔隙；烧结温度
中图分类号：TU55+1.3 文献标识码：A 文章编号：1001-702X（2019）09-0117-06
Effect of SiO2 on structural strength and porosity of sludge sintered ceramsite
QIN Jinyi，FENG Shuo，FANG Jiao，ZHANG Minghui，JIAO Yijing，CHEN Zhexin
（School of Civil Engineering，Chang'an University，Xi'an 710061，China）
Abstract：Municipal sludge is rich in metal oxides to promote the formation of crystals. At high temperatures，organic matter gas can be used as a pore forming agent，and released heat is beneficial to the increase of internal sintering temperature. So sludge sintered is beneficial to the preparation of ceramsite. The results show that the sintered ceramsite has the higher strength in the zone：SiO2=62%，Al2O3=14%，other oxides=24%. The strengths is 4.89 MPa，and the grain density is 1320 kg/m3，which meets the requirements of GB/T 17431.1—2010 "Lightweight Aggregates and Its Test Method Part 1：Lightweight Aggregates" for 800-grade artificial light aggregate. The triangular phase diagram established by SiO2，Al2O3 and other oxidized components in the ceramsite is refined. The optimum temperature for sintering is 1050 ℃. The release of heat during sludge sintering facilitates the formation of liquid phases and the accumulation of small pores therein at high temperatures. However，the gas released from combustion of the sludge will disturb the small pores convergence，and the two effects will compete with each other. Therefore，the assumption of the formation of internal pores and structures in the sintering of sludge ceramsite is proposed.
Key words：sludge ceramsite，SiO2，compressive strength，pores，sintering temperature