Research On Proppants Preparation With Waste Ceramic Sands Instead Of Aluminum Source

Bauxite is the main raw material for the preparation of ceramsite proppant.At this stage,high-grade bauxite resources are scarce,causing prices to rise,so it is very important to seek alternatives for high-grade bauxite.The waste ceramic sands are the agglomerate produced after high-temperature calcination in a furnace and the particle size does not meet the specifications after sieving.Their chemical composition contains a high content of Al₂O₃,and the shrinkage is little and easy to sinter.However,it was discarded without reasonable treatment,which not only caused a waste of aluminum resources,but also occupied a lot of land resources.In order to make rational use of waste ceramsite sands,two kinds of waste ceramsite sands were recycled to prepare proppant,by adding low-grade bauxite and potash feldspar as mixed raw materials in this work.In addtion,the X-ray diffractometer(XRD)and scanning electron microscope(SEM)were applied to characterize the phase composition and microstructure of the proppant.At the same time,the performance indicators of the green bodies and proppants were tested,and the effects of sintering temperature and waste ceramsite sands addition on the structure and performance of proppants were also explored.Combining the difficulty of ceramsite ball formation and the degree of de-powdering,the most suitable amount of waste ceramsite sands were selected.On the basis of the above-mentioned experiments,aiming at the problems of granulating and efflorescence caused by the introduction of waste ceramsite sands,the sodium carboxymethyl cellulose(CMC)was used as a binder,and the effect of CMC addition on the ball molding process,structure and performance of ceramsite proppants was studied,and the optimized CMC addition was selected.The main results are as follows:(1)The influence of different sintering temperature on the structure and performance of proppant was studied,and the final sintering temperature was selected as 1260?.The proppant prepared at this temperature has a high degree of internal densification and good crush resistance.(2)Combined with the influence of the addition of waste ceramsite sands on the granulation process,the influence of the added amount of waste ceramsite sands on the structure and performance of the proppant was studied.When the sintering temperature is 1260?,25 wt.%of high aluminum waste ceramsite sands is the most suitable,the powder removal rate is 15.81%,the bulk density is 1.38 g·cm^-3,and the apparent density is 2.69 g·cm^-3,meeting the requirements for use under 35 MPa and 42 MPa closed pressure.Similarly,the optimal additive amount of low aluminum waste ceramsite sands is 30 wt.%,and the corresponding powder removal rate is 9.42%,the bulk density is 1.45g·cm^-3,the apparent density is 2.7 g·cm^-3,which meets the requirements for use.The above products all satisfy the industry standard requirements of 30/50 mesh for low density and high strength proppants.(3)In order to solve the practical problems of granulating and efflorescence,the binder CMC was adding to improve the granulating process,and the effect of CMC addition on the structure and performance of the proppant is studied.When the CMC amount is 0.2 wt.%,the proppant prepared at 1260?has the best performance,less pores in the ceramsite section.The bulk density is 1.46 g·cm^-3,the apparent density is 2.68 g·cm^-3,meet the requirements for use under 35 MPa?42 MPa and 52MPa closed pressure,which meets the requirements of the low-density and high-strength proppant.