Technology for preparing calcium sulfate whisker from dimethyl cyanoamino di-tyiocarbonate wastewater

A technology of dimethyl cyanoimide dicarboxylate and calcium sulfate whiskers, which is applied in the directions of single crystal growth, single crystal growth, crystal growth, etc., and can solve problems such as processing difficulty

Active Publication Date: 2014-07-23
南京科硕生化科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the production of 1 ton of crude dimethyl dicarboxylate will produce 3-4 tons of 30-35% sulfuric acid wastewater, and the wastewater contains a large amount of calcium ions and some organic impurities, which brings great difficulties to subsequent treatment.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0009] Take 1500ml of dimethyl dicarboxylate wastewater in a 2000ml three-necked bottle, equip it with a thermometer, a water separator and a reflux condenser, and heat it slowly in an oil bath. When the temperature rises to 85°C, yellow organic matter slips out. When the water separator separates 8ml of yellow organic matter, remove the water separator and replace it with a reflux device, then add 5g of crystallization guide agent, continue to heat up to 96-100°C, and after stirring for 20 minutes, a large amount of white needle-like fibrous solids are precipitated , continue to reflux for 1 hour, then cool down to 25° C., age for 2 hours, filter to obtain 400.5 g of white needle-like fiber solids, and centrifugally dry to obtain 340.4 g of calcium sulfate whisker product.

Embodiment 2

[0011] Take 1200ml of dimethyl dicarboxylate wastewater in a 2000ml three-necked bottle, equip it with a thermometer, a water separator and a reflux condenser, and heat it slowly in an oil bath. When the temperature rises to 80°C, yellow organic matter slips out. When 10ml of yellow organic matter is separated from the water separator, remove the water separator and replace it with a reflux device, then add 8g of crystallization guide agent, continue to heat up to 96-105°C, and after stirring for 10 minutes, a large amount of white needle-like fiber solids are precipitated , continue to reflux for 1 hour, then cool down to 20° C., age for 2.5 hours, filter to obtain white needle-like fiber solid 260, and centrifugally dry to obtain 221 g of calcium sulfate whisker product.

Embodiment 3

[0013] Take 30L cyanoimide dimethyl dicarboxylate waste water in a 50L double-layer glass reactor, equipped with a thermometer, a water separator and a reflux condenser, and put the jacket into an oil bath to heat slowly. When the temperature rises to 90°C, The yellow organic matter slipped out. When the water separator separated 90ml of yellow organic matter, remove the water separator and replace it with a reflux device, then add 50g of crystallization guide agent, and continue to heat up to 96-98°C. After stirring for 30 minutes, there are a lot of white Acicular fiber solids were precipitated, and the reflux was continued for 2.5 hours, then cooled to 25° C., aged for 2.5 hours, filtered to obtain 6.5 Kg of white acicular fiber solids, and centrifugally dried to obtain 5.5 Kg of calcium sulfate whisker product.

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Abstract

The invention discloses a technology for preparing calcium sulfate whisker from dimethyl cyanoamino di-tyiocarbonate wastewater. The technology comprises the following steps: pretreating at the temperature of 70-90 DEG C; distilling organic impurities out of wastewater by azeotropic distillation; adding 0.1-1% of crystallization director in the wastewater; heating to 90-105 DEG C; stirring for 10-30 minutes to separate out white fiber-shaped solids; performing reflux for 1-3 hours; cooling to 20-30 DEG C; aging for 2-3 hours; and performing centrifugal drying to obtain a calcium sulfate whisker product with length of 50-300 micrometers and diameter of 1-20 micrometers. According to the method, the organic impurities in the wastewater are removed by azeotropic distillation, so that the influences of the impurities on the morphology of the calcium sulfate whisker are reduced.

Description

technical field [0001] The invention relates to a process for preparing calcium sulfate whiskers, in particular to a process for preparing calcium sulfate whiskers with dimethyl dicarboxylate wastewater. Background technique [0002] Dimethyl cyanamide dicarboxylate, also known as dimethyl cyanamide dicarboxylate, is a light yellow or off-white crystalline powder. The main intermediate of Ding. At present, the domestic production process mainly uses lime nitrogen, carbon disulfide, and dimethyl sulfate as raw materials. After the lime nitrogen is hydrolyzed, it reacts with carbon disulfide to obtain the dicalcium salt of cyanoimide dicarboxylate, and the obtained calcium salt is methylated by excess dimethyl sulfate. Finally, cool and crystallize in the solution to obtain dimethyl cyanoimide dicarboxylate, and obtain the crude product of dimethyl cyanoimide dicarboxylate after centrifugation. At present, the production of 1 ton of crude dimethyl dicarboxylate will produce ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B7/00C30B29/22C30B29/62
Inventor 宋石磊
Owner 南京科硕生化科技有限公司
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