Method for preparing calcium sulfate whisker through recrystallization

A calcium sulfate whisker and recrystallization technology, which is applied in chemical instruments and methods, calcium/strontium/barium sulfate, single crystal growth, etc., can solve the problems of difficult industrial application and high cost, and achieve resource utilization and easy Operation, low energy consumption effect

Active Publication Date: 2015-06-24
XIANGTAN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to provide a simple and efficient method for preparing recrystallized calcium sulfate whiskers, aiming at the problems of high temperature and high pressure conditions in the existing calcium sulfate whisker preparation technology, high cost, and complicated regulation and control that lead to industrial application difficulties. Introduce as few interfering substances and simplify the control factors as possible in the system, and use the principle of dissolution-recrystallization to prepare calcium sulfate whiskers. Under normal pressure, choose sulfuric acid solution commonly used in industry as the reaction medium. The concentration of sulfuric acid solution changes with temperature, and the temperature change and regulation are used to realize the dissolution-recrystallization process, and grow into whisker-like calcium sulfate dihydrate whiskers, which can be further processed into hemihydrate and anhydrous calcium sulfate whiskers.

Method used

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  • Method for preparing calcium sulfate whisker through recrystallization
  • Method for preparing calcium sulfate whisker through recrystallization
  • Method for preparing calcium sulfate whisker through recrystallization

Examples

Experimental program
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Embodiment 1

[0032] Add 110g of calcium sulfate dihydrate reagent to 1L of sulfuric acid solution with a mass percentage concentration of 14%, stir evenly, and at the same time heat to 85°C at a rate of 1.5K / min to dissolve, then stand still, and adjust the jacket cold air through the PID control system The flow rate of the suspension is reduced to 20°C at an average rate of 0.5K / min, and the temperature is maintained for 0.5h. The product is filtered and washed with water, and then dried at 60°C for 1h to obtain an aspect ratio of 50. Calcium sulfate dihydrate whiskers at ~110.

Embodiment 2

[0034] Add 6kg of gypsum ore (calcium sulfate content ≥70%) with a particle size of ≤3cm into a tank filled with 200L of sulfuric acid solution with a concentration of 25% by mass and stir, while heating at a rate of 2.0K / min to 90°C to dissolve and then reduce Stirring strength or standing still; pump the upper suspension into the crystallization reactor for stirring, adjust the flow rate of the jacket cold air through the PID control system, so that the temperature of the suspension drops to 20°C at an average rate of 1.0K / min, and maintain the temperature Aging for 1 hour; filter the product through vacuum, and wash with water to meet the quality requirements; put the separated solid phase product in an oven and dry at 60°C for 1 hour to obtain calcium sulfate dihydrate whiskers with an aspect ratio of 50~110 .

Embodiment 3

[0036] Add 1kg of desulfurized gypsum into a tank containing 100L of sulfuric acid solution with a mass percentage concentration of 35%, stir evenly, and at the same time, heat at a rate of 0.5K / min to 75°C to dissolve and let it stand; pump the upper suspension into the crystallization reactor Stir, adjust the flow of cold water in the jacket through the PID control system, reduce the temperature of the suspension to 20°C at an average rate of 1.5K / min, and keep the temperature for aging for 0.5h, filter the product and wash it with water, and then cool it at 60°C Drying for 1 hour under the hood to obtain calcium sulfate dihydrate whiskers with an aspect ratio of 50-180.

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Abstract

The invention discloses a method for preparing a calcium sulfate whisker through recrystallization. The method is characterized in that the method comprises the steps of (1), conducting program control on heating and dissolution courses: putting a raw material with a main ingredient of calcium sulfate into a sulphuric acid solution for stirring, heating simultaneously, heating a mixture to 60-95 DEG C at a certain rate with the adoption of the program control, dissolving for 20min-1h, (2), conducting the program control on cooling and recrystallization courses: using the program control to cool a suspension obtained by dissolution to 10-30 DEG C, ageing for 20min-2h, (3), conducting separating and washing courses: conducting solid-liquid separation on the suspension, washing a separated solid-phase product, and (4), conducting a drying course: drying the washed solid-phase product at a certain temperature, and obtaining the calcium sulphate dihydrate whisker. The calcium sulfate whisker is prepared by utilizing a recrystallization principle under an ordinary-pressure mild condition, and a relatively economical technological approach can be provided for the resource utilization of industrial by-products such as desulfurization gypsum and phosphogypsum.

Description

technical field [0001] The invention belongs to the technical field of preparation of calcium sulfate inorganic mineral whiskers, and specifically relates to the preparation of calcium sulfate whiskers by using the principle of recrystallization under normal pressure and mild conditions, which can be used for resource utilization of industrial by-products such as desulfurized gypsum and phosphogypsum Provide a more economical technical approach. Background technique [0002] Calcium sulfate whisker refers to a whisker-like single crystal that grows in the form of a single crystal under certain conditions and is similar to a short fiber (diameter is generally between 0.01~10μm, and the aspect ratio is 5~1000). It is an environmentally friendly inorganic material. It has important uses in the fields of construction, medicine, plastics, rubber and environmental protection, and is currently used as a reinforcing component of composite materials. The disclosed main methods for p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B7/08C30B29/22C30B29/62C01F11/46
Inventor 杨柳春陈晓娟陈敏张俊丰黄妍
Owner XIANGTAN UNIV
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