Process for producing PVC (polyvinyl chloride) section bar by taking phosphogypsum as filler

Abstract

The invention provides a process for producing a PVC (polyvinyl chloride) section bar by taking phosphogypsum as a filler. The PVC section bar is prepared from the following raw materials in parts by weight: 70-100 parts of polyvinyl chloride resin, 30-45 parts of the phosphogypsum, 3-6 parts of a stabilizer, 0.5-2 parts of an antioxidant, 1-2 parts of a lubricant and 5-10 parts of a composite plasticizer. The process is mainly characterized in that the phosphogypsum is treated, crushed, soaked in a calcium hydroxide solution with the mass concentration of 10-40%, and roasted at the temperature of 600-900 DEG C after dehydration, then soaked in water, roasted at the temperature of 163-400 DEG C after dehydration to obtain anhydrite; and the anhydrite is ground into powder of 400-800 meshes. According to the process, a phosphogypsum crystal is modified, so that the phosphogypsum replaces calcium powder in the preparation process of a conventional PVC section bar, the source of the calcium powder for PVC is expanded, the cost of the calcium powder for PVC production is reduced, the comprehensive utilization way of the phosphogypsum is expanded, and the comprehensive utilization rate of the phosphogypsum is improved.

Description

technical field [0001] The invention relates to the technical field of PVC pipe production, in particular to a process for producing PVC profiles by using phosphogypsum as a filler. Background technique [0002] Phosphogypsum is the solid waste of the phosphate fertilizer industry, and phosphoric acid is the foundation of the phosphate fertilizer industry. The wet process phosphoric acid production process is the most commonly used phosphoric acid production process. In the wet-process phosphoric acid production process, sulfuric acid is first used to decompose phosphate rock powder to produce extraction slurry, and then filter and wash to obtain phosphoric acid, and phosphogypsum waste will be generated during the process of filter and wash. Generally, about 5-6 tons of phosphogypsum are produced for every ton of phosphoric acid produced, and 2.5-5 tons of phosphogypsum are discharged for every ton of diammonium phosphate produced. With the rapid development of my country...

AI Technical Summary

Problems solved by technology

Therefore, a large number of researchers began to engage in the comprehensive utilization research of phosphogypsum, and used phosphogypsum as a raw material for building materials, such as thermal insulation blocks, etc.; some researchers used it as a raw material for the preparation of calcium oxide and sulfur dioxide etc.; but despite this, the annual comprehensive utilization rate of phosphogypsum is less than 10%, making the comprehensive utilization and development of phosphogypsum still need to further increase the process