Research On Effect Of Particle Size Distribution Of Raw Materials On The Properties Of Ceramic Proppants

Ceramic proppants is widely used in hydraulic fracturing,which can support fracture and increase fracture conductivity.At present,high-grade bauxite is mainly used as the main raw material in China,and manganese powder and dolomite are added as additives to prepare ceramic proppants.However,influenced by the current environmental policy,the cost of purchasing high-grade bauxite is increasing,and the profit of ceramic proppants is greatly reduced.Secondly,the sintering temperature of ceramic proppants is generally higher,and its fuel cost is greatly increased due to the"gas shortage".The existence of these two problems makes the development of ceramic proppans manufacturers greatly restricted or even unsustainable.In view of the problems existing in the actual production of ceramic proppants,this paper mainly studies the influence of particle size distribution of raw materials on the properties of ceramic proppants,using low-grade bauxite as the main raw material and feldspar as the auxiliary material,so as to realize the preparation of low-density and high-strength ceramic proppants at low cost and low temperature.The main results are as follows:?1?The effect of feldspar content on the properties of ceramic proppants was studied.The results show that feldspar can reduce the sintering temperature of ceramic proppants.When the optimum feldspar content is 15wt.%,the sintering range of ceramic proppants which meets the requirement of 35MPa is 1220?-1300?.The bulk density and apparent density ranges are 1.36 g/cm³-1.40 g/cm³,2.61 g/cm³-2.62 g/cm³ respectively.It belongs to low density ceramic proppants and can be used for oil and gas exploitation.?2?The effect of ball milling time of bauxite on the properties of ceramic proppants was studied.The results show that prolonging the ball milling time of bauxite can improve the crushing strength of ceramic proppants to a certain extent,but it still does not meet the requirements.This method is not recommended in the actual produ ction of ceramic proppants.?3?The effect of ball milling time of feldspar on the properties of ceramic proppants was studied.The results show that prolonging ball milling time of feldspar can significantly reduce breakage ratio of ceramic proppants.When feldspar is milled for 6 hours,the sintering temperature range for 52 MPa is 1260?-1300?,the corresponding bulk density and breakage ratio are 1.46 g/cm³-1.48 g/cm³,6.97%-8.27%respectively,and the apparent density is 2.70 g/cm³.When the feldspar is milled for 8 hours,the sintering temperature which meets the requirements of 52 MPa ranges from 1240?to 1300?.The corresponding bulk density,apparent density and breakage ratio ranges are 1.45 g/cm³-1.48g/cm³,2.68 g/cm³-2.72 g/cm³ and 6.49%-8.72%,respectively.The low density and high strength ceramic proppants can be prepared by this method.?4?Orthogonal experiments are carried out to study the effects of various factors on the properties of ceramic proppants,which show that the ball milling time of fel dspar had the greatest influence on the bulk density,apparent density and breakage ratio of ceramic proppants.The optimum combination is A₃B₁C₄-bauxite ball milling for 4h,feldspar ball milling for 8h and sintering temperature for 1280?.