Study On The Technology Of Preparing Ceramsite By Adding Oily Sludge To Domestic Sludge

As a by-product in the process of crude oil exploitation and refining,sludge is classified as hazardous waste because it is rich in heavy metals,organic poisons and pollutants,which is seriously harmful to nature and human beings.however,the current way of treating sludge is unable to strike a balance between resource utilization and harmlessness.Domestic sludge is the waste produced by sewage treatment plant,which not only wastes a lot of land,but also has potential danger because it contains a certain amount of highly pathogenic bacteria.Domestic sludge contains a certain amount of Si O₂,Al₂O₃and organic matter,so it has the resource potential of preparing ceramsite.In this paper,through the analysis of the basic physical properties of the raw materials for the preparation of ceramsite,and the regulation of raw material ratio and roasting process,the basic properties of ceramsite were optimized.According to the design idea of core-shell structure,the basic characteristics of traditional sludge ceramsite were optimized in order to stabilize the harm of oil sludge,and the surface coated ceramsite with higher performance was prepared.By using the method of theoretical analysis,the phase change during the roasting process of ceramsite was studied systematically,and the properties,morphology and phase of ceramsite were characterized.Firstly,the effects of raw material ratio and roasting process conditions on the properties of two kinds of sludge ceramsite were analyzed by single factor experiment.When domestic sludge is 50%,the fly ash is 30%,the content of clay and zeolite powder is 10%,the preheating temperature is 350℃,the preheating time is 25min,the roasting temperature is1150℃,and the roasting time is 15min.Sludge ceramsite with a bulk density of 673.23kg/m³,a water absorption rate of 1.4%in 1 hour,and a particle strength of 949N was prepared in line with the national standard.When the proportion of oil sludge is 25%,the proportion of domestic sludge and fly ash is 37.5%,the preheating temperature is 400℃and the roasting time is 15min,the bulk density of 759.68kg/m³,1h water absorption rate of 9.36%,the particle strength of 701N sludge ceramsite and all indicators meet the national standards.Secondly,the calorific value of sludge ceramsite roasting process was studied by means of uniform formula design,and it was found that the calorific value of ceramsite after adding oily sludge was a hundred times higher than that without adding oily sludge,up to841.14KJ/kg.Only 8.43KJ/kg at most.This shows that the burning swelling property of ceramsite can be effectively improved by adding oil sludge.The phase change of ceramsite roasting process was studied by Fact Sage software,and it was found that the suitable temperature range for ceramsite roasting was 1200℃～1300℃.In the phase diagram of the Si O₂-Al₂O₃-Fe₂O₃ternary system,as the Mg O content increases from 0.5%to 3.5%,the liquid phase region expands,and as the K₂O+Na₂O content increases from 1.5 to 6.0%,the liquid phase region increases.expand.Finally,the dosage of domestic sludge was increased by optimizing the formula design,and the surface-coated ceramsite was prepared by wrapping clay and zeolite powder.performance.At the same time,the core-shell structure can not only realize the resource utilization of sludge,but also realize harmless.When the oil sludge content is 25%,the domestic sludge content is 47.5%,and the fly ash content is 27.5%,the preheating temperature is 500℃,the preheating time is 30min,the roasting temperature is 1250℃,and the roasting time is 15min.The bulk density was reduced from 634.46kg/m³to 572.24kg/m³,the 1h water absorption rate was reduced from 10.71%to 7.42%,and the particle strength was increased from 528N to 878N.