Preparation Of High-strength Lightweight Ceramsite From Demagnesium Boron Mud And Oil Shale Semi-coke

Oil shale semi-coke and boron mud are solid wastes produced by extracting shale oil from oil shale,mining from boron iron ore,and producing boric acid.Their longterm storage not only takes up a large area of land,but also affects the ecology.The environment has an adverse effect.In recent years,resource utilization has been the focus of solid waste research.Due to the high content of magnesium in boron mud,magnesium can generally be extracted to recover magnesium resources,but solid wastes such as demagnesium boron mud will still be generated.This study uses oil shale semi-coke and demagnesium boron mud as raw materials to prepare high-strength light ceramsite,which can realize the high-value,bulk and full-component comprehensive utilization of oil shale semi-coke and boron mud,and has broad application prospects.This study tested the elemental composition of oil shale semi-coke and demagnesium boron mud,investigated the influence of binder,foaming agent and other auxiliary materials on the performance of ceramsite,and explored that sodium carbonate and carbon powder are foaming agents,respectively.The firing mechanism of ceramsite at the time,the influence law of the preheating system and firing system was analyzed,and the key factors and firing mechanism of the firing of high-strength and light-weight ceramsite were explored.The main research results are as follows:(1)The material ratio of the ceramsite raw meal will significantly affect the performance of the ceramsite.When the mass ratio of degreased boron mud to oil shale semi-coke is 1:1,and the additive amount of binder sodium silicate is 3%,The compressive strength of the prepared ceramsite can reach 14.72 MPa,but the organic matter in the oil shale semi-coke does not play a role in foaming.The apparent density of the ceramsite is as high as 1802.3 kg/m3,which cannot meet its light weight requirements,And after adding 10%Na2CO3 as a foaming agent,the compressive strength of the ceramsite after sintering at 1070℃ can still reach 11.50 MPa,and its porosity,apparent density,bulk density and cylinder compressive strength are respectively 22.63%,1398.33 kg/m3,8 9 9 kg/m3,and 12.21 MPa,its performance can meet the "GBT17431.1-2010 Lightweight Aggregate and test method" standard.(2)For the first time,the ImageJ grayscale analysis method was used to explore the foaming law in the ceramsite firing process.The research results show that when the firing temperature is low,the gas after the decomposition of Na2CO3 is difficult to escape due to insufficient melting of the ceramsite surface.The ceramsite accumulates to form a large cavity;when the firing temperature is too high,the gas after Na2CO3 decomposition will escape too quickly,and the molten minerals inside the ceramsite quickly filled the pores,which caused the bubbles to be mainly distributed in the ceramsite of outer surface.(3)Through the phase analysis of the high-strength lightweight ceramsite prepared with Na2CO3 as the foaming agent,it was found that the quartz,phlogopite,hematite,amphibole and enstatite in the raw meal were converted into sodium pyrite Stone,forsterite and clinostatite form a structure with forsterite as the filling and albite as the framework,which can promote the firing of ceramsite with high strength and low density.