Research On Yunnan Phosphorus Gypsum Building Putty Powder Of Interior Wall And Evaluation Of Social Benefits

Phosphogypsum is the production of phosphoric acid phosphate discharge industrial waste, with the rapid development of China’s phosphorus chemical enterprises, annual emissions of phosphogypsum soaring, it has become China’s largest number of industrial by-product gypsum, and its annual output is almost comparable to the annual output of natural gypsum. A lot of phosphogypsum stack in place and along the river, even into the ocean, this approach will undoubtedly cause great environmental pollution. The phosphogypsum resource recycling can not only reduce the environmental harm phosphogypsum, but also save natural gypsum resources,and bring considerable economic and social benefits.Phosphogypsum due to impurities exhibits itself as gray and black, this situation limit the use of phosphogypsum’s materials for paint or plaster decorative materials. The whitening phosphogypsum decolorization purification treatment can improve their resource utilization greatly. First, examine the parching procedure method, parching procedure-Acid Leaching influence the formulation of phosphogypsum whiteness, then determine the parching procedure-acid infusion formulation of parching procedure temperature and solid-liquid ratio, at last depend on the orthogonal experiment obtain the parching procedure-optimum conditions of acid infusion formulation. To use the after parching procedure-phosphogypsum after acid infusion formulation whitening decolorizing purification process is used to configure the interior wall putty powder, first, determine the phosphorus content building gypsum retarder, and then, by orthogonal experiment phosphorus obtain other components of the optimal interior gypsum-based building putty powder, finally,added wood fiber into the phosphorus construction gypsum-based dry powder putty optimal formulation optimization, make out to flexible putty. On the basis of experiments, evaluates recycling projects for the exploitation of phosphogypsum of social evaluation. The results show:1. Parching procedure-acid infusion formulation can effectively increase the whiteness of phosphogypsum, especially when sulfuric acid infusion effect is most obvious. Finally, the best decolorization whitening phosphogypsum obtained experimental conditions were:parching procedure time is 40min, parching procedure temperature at 400 ℃, acid extraction time is 60min, acid extraction temperature at 90 ℃　, sulfuric acid mass fraction of 20%, the solid-liquid ratio isl:4.Under these conditions, the repeatability of experiments made phosphogypsum whiteness increased from 32.4% to 88.5%. Phosphorus gypsum building after decolorization whitening obtained in line with GB/T 9770-2008 "Gypsum" physical performance requirements.2. By use of citric acid and six partial sodium phosphate as compound retarder to get best effect, their content of 0.1% and 0.15% respectively. After optimizing with wood fiber,obtained phosphorus gypsum-based building optimal flexible putty powder formula is:P-building gypsum 700g, dispersible polymer powder 15g, heavy calcium carbonate 150g, talc 65g, hydroxypropyl methyl cellulosel.5g, bentonite 50g, composite retarder 1.75g, wood fiber 16.75g. Its physical properties are in line with JG/T 298-2010 "building indoor putty" in pliable type (R) requirements.3. Construction of the development and utilization of phosphogypsum recycling project on social evaluation system, by the fuzzy comprehensive evaluation method for social development and utilization of phosphogypsum recycling projects were evaluated, the final results of the evaluation show that exploitation of gypsum recycling can bring good social benefits.