Method for preparing modified calcium sulfate whisker by using desulfurization gypsum

A calcium sulfate whisker and desulfurization gypsum technology, applied in chemical instruments and methods, calcium/strontium/barium sulfate, single crystal growth, etc., can solve problems such as complex process, difficult realization, and difficult industrial scale-up and mass production, and achieve The preparation process is green and environmentally friendly, the production cost is low, and the modification effect is good.

Active Publication Date: 2011-03-30
JIANGSU EFFUL SCIENCE AND TECHNOLOGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that in the surface treatment process, the surface of the whiskers needs to be sprayed with polyvinyl alcohol. This surface treatment process is not only difficult for industrial scale-up and mass production, but also difficult for the sprayed polyvinyl alcohol solution to dissolve in calcium sulfate. Whiskers are comprehensive, in short, the process is complex and difficult to realize
Shi Peiyang et al. (Shi Peiyang, Liu Chengjun, Jiang Maofa, the method for preparing calcium sulfate whiskers by using flue gas desulfurization gypsum, CN 101311337A) used desulfurization gypsum as raw material, and obtained a length of 15 mm after slurry mixing, high temperature crystallization, drying and modification. ~240um, calcium sulfate whiskers with a diameter of 0.2~4um, the disadvantage of this method is that the whiskers are modified after drying, and the fibrous structure of the whiskers is easily damaged during the modification process, reducing the aspect ratio At the same time, due to the relatively complicated process, the investment in equipment has been increased in the process of building the production line, and the energy consumption in the process of preparing calcium sulfate whiskers has been increased.
[0005] In short, the predecessors have made fruitful work in the preparation of calcium sulfate whiskers by using desulfurized gypsum, but there are still problems such as complicated process, poor modification effect, and easy reduction of whisker aspect ratio during the modification process.

Method used

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  • Method for preparing modified calcium sulfate whisker by using desulfurization gypsum
  • Method for preparing modified calcium sulfate whisker by using desulfurization gypsum
  • Method for preparing modified calcium sulfate whisker by using desulfurization gypsum

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] The process steps are as follows:

[0026] ① Sieving: Sieving the desulfurized gypsum with a 0.08mm sieve to remove sand, stones and other impurities in the desulfurized gypsum. Impurities are treated as solid waste.

[0027] ②Pulping: Weigh 500g of desulfurized gypsum after sieving, measure 10L of tap water with a graduated cylinder, then mix the prepared desulfurized gypsum with water, adjust the pH of the solution to 5 with NaOH and HCl, and finally stir with a mixer for 20 second.

[0028] ③Hydrothermal reaction: Put the stirred slurry in a high-pressure reactor, control the reaction temperature to 125°C, the pressure corresponding to the temperature is about 0.232Mpa, and the holding time is 300min;

[0029] ④Whisker surface modification: Add 0.05% acrylic acid-maleic acid copolymer and 2% sodium lauryl sulfate by weight of desulfurization gypsum to the autoclave, and keep it warm for 60 minutes;

[0030] ⑤Dehydration: Use a centrifuge to separate the calcium sulfate whisk...

Embodiment 2

[0035] The process steps are as follows:

[0036] ①Sieving: sieving the desulfurized gypsum with a 1.18mm sieve to remove impurities such as sand and gravel in the desulfurized gypsum. Impurities are treated as solid waste.

[0037] ②Pulping: Weigh 3300g of desulfurized gypsum after sieving, measure 10L of tap water with a graduated cylinder, then mix the prepared desulfurized gypsum with water, adjust the pH of the solution to 10 with NaOH and HCl, and finally stir with a mixer for 60 second.

[0038] ③Hydrothermal reaction: Put the stirred slurry in a high-pressure reactor, control the reaction temperature to be 180°C, and the pressure corresponding to the temperature to be 1.052Mpa for 30 minutes;

[0039] ④Whisker surface modification: Add 0.3% potassium oleate by weight of desulfurized gypsum to the high-pressure reactor, and keep it warm for 40 minutes;

[0040] ⑤Dehydration: Use a centrifuge to separate calcium sulfate whiskers and water into solid and liquid, so that the moist...

Embodiment 3

[0044] The process steps are as follows:

[0045] ①Sieving: Sieving the desulfurized gypsum with a 1.18mm sieve to remove sand, stones and other impurities in the desulfurized gypsum. Impurities are treated as solid waste.

[0046] ②Pulping: Weigh 1000g of desulfurized gypsum after sieving, measure 10L of tap water with a graduated cylinder, then mix the prepared desulfurized gypsum with water, adjust the pH of the solution to 7 with NaOH and HCl, and finally stir with a mixer for 120 second.

[0047] ③Hydrothermal reaction: Put the stirred slurry in a high-pressure reactor, control the reaction temperature to 130°C, and the pressure corresponding to the temperature to 0.270Mpa, and the holding time for 150min;

[0048] ④Whisker surface modification: Add 5% sodium tetradecyl sulfate by weight of desulfurization gypsum to the high-pressure reactor, and keep it warm for 60 minutes;

[0049] ⑤Dehydration: Use a centrifuge to separate calcium sulfate whiskers and water into solid and liqu...

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Abstract

The invention discloses a method for preparing a modified calcium sulfate whisker by using desulfurization gypsum, comprising the following steps of sieving, pulping, performing hydro-thermal reaction and whisker surface modification, dewatering and drying, wherein the reaction temperature ranges from 107 DEG C to 180 DEG C, the concentration of desulfurization gypsum and water is 5-33wt% and the drying temperature ranges from 100 DEG C to 300 DEG C, and a modifier which is 0.05-5% of the weight of desulfurization gypsum in the calcium sulfate whisker suspension formed in hydro-thermal reaction. The invention solves the problem that CaSO4.0.5H2O whisker is easy to hydrate in the drying process tocause fracture of the whisker and enhances the compatibility of the calcium sulfate whisker and the high polymer materials. The prepared modified calcium sulfate whisker has a diameter of 0.5-6 micrometers, a length of 30-300 micrometers and a diameter ratio of 15-115 and the contact angle of water on the surface of the modified calcium sulfate whisker ranges from 12 to 140 degrees. The invention has the advantages of good modified effect, simple process, low production cost, the use of the non-toxic modifier and environmental-friendly preparation process.

Description

Technical field [0001] The invention relates to a preparation method of modified calcium sulfate whiskers, belonging to the technical field of resource recycling of industrial waste and new inorganic materials. technical background [0002] Rich coal, poor oil, and low gas are the basic characteristics of my country's energy resources. This feature determines that coal occupies a dominant position in my country's energy structure. Coal will remain the most important energy source in my country for a long time. Due to environmental protection reasons, power plants must force desulfurization when using coal for power generation. At present, most coal-fired power plants in our country use wet desulfurization technology. This process produces a large amount of desulfurized gypsum that occupies cultivated land and pollutes the environment. Therefore, deep processing of desulfurized gypsum is one thing A work of great social and economic benefits. [0003] Gypsum whiskers are small fibr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/10C30B29/62C30B7/10C01F11/46
Inventor 唐绍林唐永波万建东丁大武唐修仁刘丽娟
Owner JIANGSU EFFUL SCIENCE AND TECHNOLOGY CO LTD
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