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Preparation method of dustless damp-proof chalk

A technology of chalk and adsorbent, applied in the direction of pencil lead, household utensils, applications, etc., to achieve the effect of reasonable price

Inactive Publication Date: 2014-02-12
西安佳迅科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a preparation method of dust-free and moisture-proof chalk, which solves the problems in the prior art that the chalk dust particles are not harmful to the human body; it must also meet the needs of moisture-proof and the price is suitable

Method used

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Examples

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preparation example Construction

[0017] The preparation method of dust-free moisture-proof chalk of the present invention is to implement according to the following steps:

[0018] Step 1, weigh the following components according to mass percentage, 45%-55% calcium carbonate, 45%-55% calcium sulfate (gypsum), 1%-2% clay, 2%-5% adsorbent, Total 100%.

[0019] Step 2, heat the raw gypsum to a temperature of 60°-80° to partially dehydrate it into mature gypsum, then add 10%-15% water to the plaster of paris and stir, then add 45%-55% calcium carbonate, 1% -2% clay and 2%-5% adsorbent are stirred together to form a paste, poured into the model and solidified to obtain a formed chalk.

[0020] The reaction of raw gypsum to mature gypsum is (requires heating):

[0021] 2CaSO 4 2H 2 O=2CaSO 4 0.5H 2 O+3H 2 o

[0022] The reaction of adding water to plaster of paris to turn it into raw gypsum is (just normal temperature):

[0023] 2CaSO 4 0.5H 2 O+3H 2 O=2CaSO 4 2H 2 O.

[0024] Step 3: Apply a layer o...

Embodiment 1

[0026] Step 1, weigh the following components according to mass percentage, 45% calcium carbonate, 50% calcium sulfate (gypsum), 2% clay, 3% adsorbent, totaling 100%.

[0027] Step 2, heat the raw gypsum to 60°C to make it partially dehydrated into mature gypsum, then add 10% water to the plaster of paris and stir, then add calcium carbonate, 2% clay, and 3% adsorbent, and stir together to form Paste, poured into the model to solidify to obtain shaped chalk.

[0028] Step 3, apply a layer of paraffin wax on the chalk circumference surface obtained in step 2, and it is ready.

Embodiment 2

[0030] Step 1, weigh the following components according to mass percentage, 52% calcium carbonate, 45% calcium sulfate (gypsum), 1% clay, 2% adsorbent, totaling 100%.

[0031] Step 2: Heat the raw gypsum to 80° to make it partially dehydrated into mature gypsum, then add 15% water to the plaster of paris and stir, then add calcium carbonate, clay, and adsorbent, stir together to form a paste, and pour it into the model Solidify to obtain shaped chalk.

[0032] Step 3, apply a layer of paraffin wax on the chalk circumference surface obtained in step 2, and it is ready.

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PUM

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Abstract

The invention discloses a preparation method of a dustless damp-proof chalk. The preparation method comprises the following steps: 1. weighing the following components in percentage by mass: 45-55% of calcium carbonate, 45-55% of plaster stone, 1-2% of clay and 2-5% adsorbent, wherein the sum of the percentages by mass is 100%; 2. heating up the plaster stone to 60-80 DEG C to partially dehydrate the plaster stone to form calcined gypsum, adding 10-15% of water into the calcined gypsum, stirring, adding 45-55% of calcium carbonate, 1-2% of clay and 2-5% adsorbent, stirring the components to form paste, filling the paste into a model, and solidifying the paste to obtain a formed chalk; and 3. coating a layer of damp-proof material on the circumferential surface of the chalk obtained in the step 2 to obtain the dustless damp-proof chalk. The chalk prepared by the method disclosed by the invention is particularly suitable for use and storage in wet areas.

Description

technical field [0001] The invention belongs to the technical field of teaching supplies, and relates to a preparation method of dust-free and moisture-proof chalk. Background technique [0002] The chalk used now mainly contains two kinds of common chalk and dust-free moisture-proof chalk, and its main component is calcium carbonate (limestone) and calcium sulfate (gypsum), or contains a small amount of calcium oxide. [0003] Writing on the blackboard with chalk is to apply gypsum powder to the blackboard. When wiping the blackboard, gypsum dust (chalk dust) floats in the air for a short time and then falls on the surface and the ground near the blackboard. Dust-free and moisture-proof chalk is an improved product of ordinary chalk, which is used to eliminate chalk dust pollution in classrooms. Generally, oils or polyalcohols are added to ordinary chalk as adsorbents, and then fillers with larger specific gravity, such as clay, marl, cement, etc., can increase the specif...

Claims

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Application Information

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IPC IPC(8): C09D13/00
Inventor 王祯怡
Owner 西安佳迅科技有限公司
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