Method for producing land plaster whiskers from phosphoric acid

A technology of gypsum whiskers and phosphoric acid, which is applied in the field of manufacturing gypsum whiskers, can solve problems such as slow production speed and complex production equipment, and achieve the effects of low production costs, reduced production costs, and neat growth

Inactive Publication Date: 2005-02-23
QINGDAO UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Slow production speed and c

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Example 1. A method of making gypsum whiskers in phosphoric acid. It includes the steps of preparing phosphoric acid leaching solution, preparing gypsum whisker suspension, preparing semi-water or anhydrous gypsum whisker and the like. The preparation step of phosphoric acid leaching solution is to use excess phosphoric acid with a concentration of 35% to carry out leaching chemical reaction with phosphate rock, control the temperature at 95°C, and after 2 hours of reaction, separate the liquid phase and filter it to obtain 3 PO 4 3-4mol / L, Ca 2+ 0.8-1.2mol / L phosphoric acid leach solution. The preparation step of the gypsum whisker suspension is to gradually add the phosphoric acid leaching solution into the sulfuric acid solution with a concentration of 32% under stirring, and stir and react at 100°C for 120 minutes to form gypsum whiskers suspended in phosphoric acid or sulfur phosphorus mixed acid. The preparation step of the hemihydrate or anhydrous gypsum w...

Embodiment 2

[0016] Example 2. A method of making gypsum whiskers in phosphoric acid. It includes the steps of preparing phosphoric acid leaching solution, preparing gypsum whisker suspension, preparing semi-water or anhydrous gypsum whisker and the like. The preparation step of phosphoric acid leaching solution is to use excess phosphoric acid with a concentration of 40% to carry out leaching chemical reaction with phosphate rock, control the temperature at 50°C, and after 3 hours of reaction, separate the liquid phase and filter to obtain 3 PO 4 3-4mol / L, Ca 2+ 0.8-1.2mol / L phosphoric acid leach solution. The preparation step of the gypsum whisker suspension is to gradually add the phosphoric acid leaching solution into a sulfuric acid solution with a concentration of 35% under stirring, and stir and react at 50°C for 130 minutes to form gypsum whiskers suspended in phosphoric acid or sulfur phosphorus mixed acid. The preparation step of the hemihydrate gypsum whisker is to filter...

Embodiment 3

[0017] Example 3. A method of making gypsum whiskers in phosphoric acid. It includes the steps of preparing phosphoric acid leaching solution, preparing gypsum whisker suspension, preparing semi-water or anhydrous gypsum whisker and the like. The preparation step of phosphoric acid leaching solution is to use excess phosphoric acid with a concentration of 30% to carry out leaching chemical reaction with phosphate rock, control the temperature at 90°C, and after 3 hours of reaction, separate the liquid phase and filter to obtain 3 PO 4 3-4mol / L, Ca 2+ 0.8-1.2mol / L phosphoric acid leach solution. The preparation step of the gypsum whisker suspension is to gradually add the phosphoric acid leaching solution into a sulfuric acid solution with a concentration of 30% under stirring, and stir and react at 90°C for 150 minutes to form gypsum whiskers suspended in phosphoric acid or sulfur phosphorus mixed acid. The preparation step of the hemihydrate gypsum whisker is to filter...

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Abstract

Production of gypsum in phosphorous liquid involves preparing a phosphorous extracting liquid and a gypsum crystal whisker suspending liquid. The phosphorous extracting liquid is prepared by extracting 30 - 40% phosphorous acid with ores at 50 - 95deg.C for 2 - 4h, separating liquid phase and filtering to obtain products with H3PO4 3 - 4mol/L and Ca2+ 0.8 - 1.2mol/L. The suspending liquid is prepared by adding the said liquid into 30 - 35% sulfuric acid solution gradually, stirring and reacting at (50 - 100)deg.C for 120 - 150min. Hemi-hydrated or anhydrous gypsum whiskers are obtained after filtering the suspending liquid, cleansing with boiled water, and drying at (120 - 200)deg.C. The process reduces generating temperature and cost in production, shortens production time, and qualifies their performance, so that it can be widely used in production of gypsum whiskers.

Description

technical field [0001] The invention belongs to the technical field of gypsum whisker production, and more specifically relates to the improvement of a method for producing gypsum whiskers in phosphoric acid. Background technique [0002] Gypsum whiskers refer to rod-shaped (anhydrous, hemihydrate or dihydrate) calcium sulfate crystals with a diameter of 1-4 microns and a length of 10-200 microns. [0003] At present, there are two main methods of producing gypsum whiskers: [0004] (1) Hydrothermal method: add dihydrate gypsum with a mass fraction of less than 2% to a hydraulic heater, and convert it into needle-shaped gypsum crystals after a certain period of time under the action of saturated water vapor, then filter and dry . Due to the small solid-to-liquid ratio of the feed and the use of pressurized equipment, the production cost of gypsum whiskers remains high due to the hydraulic heating method. Therefore, it is actually difficult to industria...

Claims

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Application Information

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IPC IPC(8): C01F11/46C30B7/00C30B29/62
Inventor 陈学玺
Owner QINGDAO UNIV OF SCI & TECH
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