The Lightweight Wall Materials Of Fiber Reinforced Modified Phosphogypsum

Phosphogypsum is the solid wastes produced from phosphorous chemical enterprise.The main components of phosphogypsum is CaSO4, it contains also a small amount ofharmful impurities, including soluble P2O5, Si02, Al203, fluoride and organics. Thesesubstances affect the utilization of phosphogypsum, and make its utilization rateextremely low. The piling up of mass of phosphogypsum which is unable to be utilizedeffectively becomes the concern of people. Regarding wall materials, our country has putforward a series of policies restricting the use of clay bricks while supporting andencouraging the development of new wall materials. Using phosphogypsum as the fillerof the wall materials can not only solve the issue of consuming mass of phosphogypsum,but also promote the development of new type wall. To develop wall material by utilizingphosphogypsum has important significance for both the environmental protection andefficient use of resources.This thesis makes experiment research to the preparation of phosphogypsumlightweight wall bricks, in which the phosphogypsum is used as basic raw material, spareash， a by-product of calcined limestone is used as gelled material, supplemented by flyash as the auxiliary material. Adopting the spare ash which is rich in calcium oxide toneutralize the phosphogypsum, to make pretreatment to the phosphogypsum by addingappropriate activator. The activator makes the materials’ granules dispersed, which isbeneficial to improving system response speed, and accelerating hydration reaction.Inthis way the contribution to the strength of the building blocks has been increased. spareash can make the harmful impurities in the phosphogypsum to be transferred to inertsubstance. The activated spare ash and fly ash together ensure the strength. Theworkability of the materials will be adjusted in initial stage when the fly ash added.The optimum proportion of the phosphogypsum building blocks is determined bysingle factor experiment,50%phosphogypsum,9%spare ash,1%activator and20%fly ash. And the optimum technological conditions is obtained, water consumption is20%,wet and heated maintenance is under60°C, maintenance method is2days standardmaintenance and7days maintenance. Ideal compressive strength is gained.According to this formula, an appropriate additive system of phosphogypsum isdeveloped in this thesis, using phosphogypsum as main raw material to preparelightweight heat preservation wall materials; the direct utilization of phosphogypsum isrealized. The experimental results show that using phosphogypsum to preparelightweight heat preservation wall materials adopting the method of molding by castingis entirely feasible, to add expanded perlite on the basis of the original formula will lowerthe density of the phosphogypsum building blocks. Owing to the adding of theexpanded perlite, the compressive strength and tensile strength of the formed buildingblocks decreased, the above mentioned shortage is made up by adding appropriateamount of PP fiber. The expected goal is reached within the permitted scope ofcompressive strength when the density is of1.2or so.