Study On Preparation And Properties Of Oil Shale Slag Ceramsite

Oil shale slag is the remaining product of oil shale after dry distillation or combustion.Its production is huge,but it is not well used,resulting in a large number of accumulation,causing serious environmental pollution.The problem of recycling and use of oil shale slag is imminent.A large number of studies have shown that oil shale slag has a porous structure,has high activity,and has basic conditions for recycling.Ceramsite,as a new type of building material,has been widely used in construction due to its low density,high strength,fire resistance and earthquake resistance.The purpose of this paper is to prepare ceramsite with oil shale slag as the main raw material.The purpose of this paper is to prepare ceramic grain slag as the main raw material,and to realize the efficient utilization of oil shale slag in the preparation of ceramic grain through the optimization of the composition of ingredients and the sintering system.Based on the chemical composition of oil shale slag and the principle of maximizing the use of oil shale slag,this paper first carried out research on the basic proportion of oil shale slag ceramsite and foaming agent.The type and optimal blending amount of the foaming agent.Secondly,based on the results of thermogravimetric analysis,the preheating temperature and sintering temperature range for the preparation of oil shale slag ceramsite were initially determined.Thirdly,the heat treatment system was optimized by orthogonal experiments.The influencing factors of shale slag ceramsite preparation were analyzed,the optimal technology was determined,and performance indexes such as water absorption,bulk density and single grain compressive strength were tested and analyzed.Finally,the morphology and internal structure of the fired ceramsite were analyzed by means of XRD and SEM.The results of the study show that:The shale slag used from Beita Oil Shale Comprehensive Development and Utilization Co.,Ltd.meets the requirements for producing ceramsite in the ternary phase diagram.The foaming effect of sodium carbonate and sodium bicarbonate is good and similar,considering that sodium bicarbonate is used as The performance of the ceramsite produced by the foaming agent is greatly affected by changes in the test conditions,so sodium carbonate is used as the foaming agent.With the increase of sodium carbonate content,the bulk density of oil shale slag ceramsite gradually decreases and increases slightly.When the foaming agent content reaches 5%,the bulk density is the smallest.According to the results of thermogravimetric analysis,the oil sheet is obtained.The preheating temperature for the preparation of rock slag ceramsite is 400℃,and the sintering temperature is 1100℃.The results of orthogonal experiments show that the strength of the factors affecting the compressive strength of ceramsite single grains is:firing temperature>holding time>The amount of foaming agent.The order of influencing factors on the packing density of ceramsite is:sintering temperature>the amount of foaming agent>holding time.The order of influencing factors on the water absorption of ceramsite is:sintering temperature>holding time>the amount of foaming agent.The effect of firing temperature on ceramsite water absorption,bulk density and compressive strength of single grain is significant.Through the three-factor three-level design orthogonal test process optimization,the firing temperature was determined as 1100℃,while the holding time is 15min,admixture content is 7%.In accordance with the principle of maximizing resource utilization of shale slag,using a mix of 75%shale slag,25%fly ash,and 7%sodium carbonate,preheat it at 400 ℃ for 15 minutes,continue to heat up to 1100 ℃ and finally keep it warm.Oil shale slag ceramsite with a bulk density of 600 kg/m3,a water absorption of 0.23%for 24 hours and a single compressive strength of 7.05 MPa can be prepared in a 15 min firing process.The performance of ceramsite is in accordance with "Light Aggregate and Its Test Method Part 1:Light Aggregate"(GB/T 17431.1-2010)and "Light Aggregate and Its Test Method Part 2:Light Aggregate Test Method"(GB/T 17431.2-2010)and other national standards.