Method for utilizing solid waste ardealite to prepare gypsum whiskers

Abstract

The invention discloses a method for utilizing solid waste ardealite to prepare gypsum whiskers. According to the method, the industrial solid waste ardealite is used as a raw material. Firstly, the ardealite is subjected to washing pretreatment including the three working procedures of washing, centrifugal dewatering and lime neutralizing treatment; the ardealite is evenly stirred with water in a reactor, an upper-layer flotage of supernatant liquid is filtered out after standing, then the ardealite is slowly stirred to obtain uniform slurry, centrifugal separation, dewatering and vacuum drying are performed to obtain purified ardealite, and waste liquid produced after washing is neutralized with lime water and then can be recycled; secondly, an appropriate amount of purified ardealite is calcined, the calcined ardealite is shaken up with mixed liquor prepared from glycerine and water in certain proportion in a tubular furnace, the mixture is calcined at the 4 DEG C / min temperature rise speed under the 500 DEG C temperature condition for 2 hours, and calcined semi-hydrated gypsum whiskers can be obtained through crystallization reaction. The gypsum whiskers are prepared by means of a one-step method, energy is saved, the environment is protected, a process and the devices are novel, and the method is simple and convenient to operate and advanced in technology and facilitates industrialization.

Description

technical field [0001] The invention relates to a method for preparing gypsum whiskers from industrial solid waste phosphogypsum, and belongs to the technical field of industrial solid waste treatment and disposal. Background technique [0002] The world produces about 280 million tons of phosphogypsum every year. According to data, in 2012, the output of phosphogypsum in my country was about 70 million tons, and the cumulative stock of phosphogypsum has reached 250 million tons. few. The annual comprehensive utilization rate of phosphogypsum is only 24.28%. Except for a small amount used to replace natural gypsum as cement retarder, sulfuric acid co-production cement, soil improver, etc., most of phosphogypsum is stacked in the open air, occupying a large area. Land, and soluble phosphorus, soluble fluorine and other impurities contained in phosphogypsum will leach with rainwater, producing acidic wastewater, causing serious pollution of soil, water system and atmosphere, a...

AI Technical Summary

Problems solved by technology

[0020] Purpose of the invention: The present invention aims to overcome the above-mentioned technical defects, aiming at the complex production process and complex control existing in the existing phosphogypsum pretreatment and calcium sulfate whisker preparation technologies, which make it difficult to apply industrially, and to provide a method that utilizes solid waste A method for preparing gypsum whiskers from phosphogypsum. The method introduces as few interfering substances as possible into the system and simplifies control factors, and uses water-washed and purified phosphogypsum to be calcined into calcium sulfate hemihydrate whiskers in one step to realize the utilization of solid waste. Waste liquid can be recycled, green production, in line with national requirements for circular economy

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