Phosphogypsum New Walling Materials Research

The mainly composition of Phosphogypsum is CaSO4·2H2O,and Phosphogypsum is the solid waste of wet phosphoric acid production process, its main components containing a small amount of solubleP2O5、SiO2、Al2O3and fluoride,organic compounds and other harmful impurities. Using rich CaSO4·2H2O of Phosphogypsum for resources to manufacture new wall materials, not only well solve natural gypsum resources, but also reduce the wall materials production costs, and using high energy consumption of the of clay brick reduce, it can solve serious environment pollution problem of the phosphorus gypsum accumulation of large amount. It used recrystallization method in the topic research, curing made of material of new-style wall for difficult treatment of phosphogypsum, find the reaction rule and principle of special conditions for recrystallization made the large scale and industrialization of suing phosphogypsum waste utilization.The phosphogypsum crystallization is the use of mechanical ball milling to process which the increase phosphogypsum specific surface area and activity is enhanced, using water crystallization solidification. This topic use of recrystallization method to treat of phosphogypsum, researching the strength of phosphogypsum process influence for ball milling time, It joined the laboratory assistant grinding agent on the phosphorus gypsum grinding while mechanical ball milling process will make phosphorus gypsum particles occur sticky ball and reunion.later,adding lime to the improve phosphogypsum cohesion. Pretreatment resulted:grinding time is25min,, grinding agent content0.02%,water cement ratio of0.22, the bending strength of Phosphorus gypsum block is2.1MPa, compressive strength is8.89MPa, requirements of7.5wall materials.It studies of activator phosphorus gypsum block the intensity of excitation effect study of five kinds of activator,on on the preprocessing based. JF-1, JF-2, JF-3, JF-4, JF-5in volume2%of phosphorus gypsum block strength effect. Activator joined the results, JF-1, JF-3mixed incorporation, in addition tol%and JF-3when JF-1was1.5%, block MPa, compressive bending2.713.4MPa, requirements of10wall materials. Using of admixture increase the phosphate gypsum block strength, test using half water gypsum, fly ash, cement, on the preprocessing based on adding admixture, test results show half water gypsum and fly ash did not significantly increase the test block strength.cement parameters in15%,28d bending strength is of4.3MPa, compressive strength is18.75MPa, the strength higher than the wall material level15requirements, test of undisturbed phosphogypsum into cement and the pretreatment result of adding cement were compared, the preprocessing is the necessary premise of high strength of test block.In order to make the phosphogypsum wall materials used more extensively, adding foaming agent for light phosphorus gypsum wall materials, research of phosphorus gypsum in180℃for4h, on the preparation of half water gypsum total analysis, initial setting time is3min, because gypsum slurry in the initial setting time can not for join foam process requirements, by means of adding retarder gypsum slurry initial setting time extended, adding superplasticizer reduce gypsum standard requirement to enhance the strength, the experimental results show that, after joining the retarder admixture is0.2%, JK series superplasticizer dosage0.3%, initial setting time of27min, alkaline water rate of9%, adding foaming agent addition volume0.02%, preparation of the wall material of7days later compression strength of test block is4.6MPa, bending strength is2.2MPa, volume density of0.82g.cm-3. As load bearing wall material, the strength is higher than that of MU3.5strength standard grade, while the density of less than1.2g.cm-3standard, standard light wall material of requirements.Research on curing mechanism of phosphogypsum pretreatment show that reasonable mechanical ball milling under the action of water, phosphorus gypsum similar like half water gypsum as excitant recrystallization, adding phosphogypsum crystal grain in more dense, admixture cement is formed in the phosphorus gypsum gypsum crystallization grain and cement production of gel gel structure, the test block strength r improved further.