湖泊底泥燃烧特性及其热动力学分析

湖泊底泥为沉积于湖泊水体底部的黏土、泥沙、有机质及各种矿物的混合物,因其含有较高的SiO_2、Al_2O_3等成陶成分和一定的CaO、MgO、K_2O、Na_2O等助熔成分以及部分有机物,可作为焙烧陶粒或其他烧结制品原料进行资源化利用。本文选用湖北黄石某湖泊底泥,测定其烧失量和有机质含量,采用XRF、ICP-OES和XRD研究其物化特性,并用同步热分析-质谱联用仪(TG-DSC-MS)进行热分析,对结果进行热动力学计算。结果表明:湖泊底泥的主要成分为石英、方解石、镁方解石、云母等矿物质;其中,SiO_2含量为52.3%,Al_2O_3含量为14.41%,Fe_2O_3含量为6.89%,S含量为0.39%,P含量为0.13%,以及极少量的重金属,烧失量为14.19%,有机物含量为10.86%。湖泊底泥燃烧过程中气体释放主要发生在120～750℃阶段,主要气体有CO_2、H_2O、NO、NO_2等,不同升温速率对湖泊底泥燃烧过程无明显影响;湖泊底泥的燃烧失重过程可以分为两个阶段,利用Coats-Redfern法的一级反应模型能够很好地描述湖泊底泥的燃烧过程,在第一阶段湖泊底泥活化能约为22.00kJ/mol,可为湖泊底泥烧结制品控制反应历程和研究固化机理提供参考。

Combustion characteristics and thermodynamic analysis of lake sediments

The sediment in the lake is a mixture of clay, organic matter and various minerals. It contains SiO2, Al2O3, CaO, MgO, K2O, Na2O and some organic materials which can be used as raw materials for roasting ceramics or other sintered products. In this paper, some sediment derived from a lake in Huangshi City, Hubei Province was selected to measure the loss on ignition and the content of organic matter. XRF, ICP-OES and XRD were used to study the physical and chemical properties. Synchronous thermal analysis-mass spectrometer (TG-DSC-MS) was used in thermal analysis, and thermal analysis kinetic calculations were performed based on the results of the thermal analysis. The results showed that the main components in the sediments were quartz, calcite, magnesium calcite, mica and such on. The organic matter content was 10.86%, and the loss on ignition was 14.19%, and the content of S was 0.39% and P was 0.13%, and there was a small amount of heavy metals. The gas release during the combustion of lake sediment mainly occurs in the stage of 120 °C ~ 750 °C. The main gases are CO2, H2O, NO, NO2, etc. The different heating rates have no obvious effect on the combustion process of lake sediment. The combustion of lake sediment can be divided into two stages, the first-order reaction model of Coats-Redfern method can describe the combustion process of lake sediment well. The activation energy of lake sediment in the first stage is about 22.00 kJ/mol. So the reference is given to the control of the reaction mechanism and the research on the curing mechanism of the preparation of sintered products in lake sediments.