Preparation And Properties Of Secondary Aluminium Ash Ceramsite Proppant

In recent years,China’s high-quality economic development and industrialization process accelerated have been accompanied by a large amount of industrial solid waste.Secondary aluminum ash is a hazardous solid waste generated in the electrolytic aluminum industry.Currently,it is mainly treated through landfilling or stacking,which is not conducive to achieving resource utilization and sustainable development.In this paper,secondary aluminum ash is used as the main raw material to prepare ceramsite proppant,which not only reduces ecological environment pollution but also enables resource reuse.On the basis of a detailed analysis of the current production status of fracturing proppants at home and abroad,this article aims to explore the feasibility of preparing ceramsite proppants using solid waste secondary aluminum ash in the aluminum and electricity industry as the main raw material,and kaolin as an auxiliary material in response to the increasing scarcity of bauxite resources in China.Through a series of experimental studies such as material analysis,material ratio,granulation process,calcination temperature,performance testing,and phase characterization,combined with industry standards,the feasibility of preparing ceramsite proppant from secondary aluminum ash is judged.In order to further improve the performance of ceramsite proppant,magnesium oxide and manganese dioxide were introduced as additives,and their effects on the apparent density,bulk density,crushing rate,phase and microstructure of ceramsite apparent were analyzed and studied.A ceramic proppant with all performance indicators meeting the requirements of the proppant industry standard was prepared.The main results of the paper are as follows:(1)The feasibility of preparing ceramsite proppant using secondary aluminum ash and kaolin as raw materials at different material ratios and sintering temperatures was studied.The results showed that the ceramsite proppant prepared from secondary aluminum ash(66.7 wt%)and kaolin(33.3 wt%)as raw materials had the best performance at a calcination temperature of 1270℃and a holding time of 3 h.Its bulk density and apparent density were 1.1690 g/cm~3and 2.6435 g/cm~3,respectively,and the crushing rate was 13.36%under a closing pressure of35 MPa.(2)The main crystal phase of the sample ceramsite proppant prepared from secondary aluminum ash and kaolin is mainly corundum and mullite.With the increase of secondary aluminum ash content,the crystal phase of the sample ceramsite proppant transfers from mullite phase to corundum phase,and its anti crushing ability was improved.(3)Using secondary aluminum ash(66.7 wt%)and kaolin(33.3 wt%)as raw materials,and adding an appropriate amount of magnesium oxide as a cosolvent to prepare a sample ceramsite proppant,reduces the sintering temperature.The main crystal phases of ceramsite proppant are corundum phase,aluminum magnesium spinel phase,and a small amount of mullite phase.However,due to the high thermal expansion of magnesium oxide,the addition of magnesium oxide can significantly weaken the compressive strength of the sample,which was not improved the performance of the sample proppant.(4)Using secondary aluminum ash(66.7 wt%)and kaolin(33.3 wt%)as raw materials,adding an appropriate amount of manganese dioxide to prepare a sample ceramsite proppant,can improve its performance.When the sintering temperature is 1270℃and the addition amount is 2 wt%,the ceramsite performance was the best.The main crystal phases are corundum phase and a small amount of mullite phase.The bulk density and apparent density of ceramsite proppant were 1.2305 g/cm~3and 2.5033 g/cm~3,respectively.The crushing rate was 8.41%under the closed pressure of 35 MPa,which meets the industry standards for proppants.(5)Using secondary aluminum ash(66.7 wt%),kaolin(33.3 wt%),magnesium oxide(2wt%),and manganese dioxide(2 wt%)as raw materials,a ceramsite proppant with the main crystal phases of corundum and aluminum magnesium spinel was prepared at a lower sintering temperature(1250℃).Its bulk density and apparent density were 1.1396 g/cm~3and2.3720 g/cm~3,respectively.The crushing rate was 13.92%under a closed pressure of 35 MPa.