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A kind of precipitation calcium carbonate production process that reduces magnesium and increases calcium

A technology of precipitated calcium carbonate and production process, which is applied in the direction of calcium carbonate/strontium/barium, etc., to achieve the effect of improving quality, product quality index does not fluctuate, and quality is stable

Inactive Publication Date: 2016-01-20
云南和铄投资管理有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

CN1886340A discloses a method and equipment for producing precipitated calcium carbonate, but it does not relate to the problem of how to reduce iron and magnesium content in the product

Method used

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  • A kind of precipitation calcium carbonate production process that reduces magnesium and increases calcium
  • A kind of precipitation calcium carbonate production process that reduces magnesium and increases calcium
  • A kind of precipitation calcium carbonate production process that reduces magnesium and increases calcium

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] The technological process of the present embodiment is:

[0051] 1) Kiln gas purification process

[0052] The kiln gas produced by the lime kiln 5 (see "Inorganic Salt Technology", Zhou Youying. Chemical Press, page 168) is passed into the lower part of the desulfurization tower 101, and the desulfurized kiln gas flows out from the top of the desulfurization tower 101, and then enters the washing The lower part of the tower 102 flows out from the top of the washing tower 102 (at this time, the temperature of the kiln gas drops to 40°C, CO 2 The volume content of the kiln gas is 30% of the kiln gas), and enters the gas-liquid separator 103;

[0053] Among them, the liquid phase in the desulfurization tower is water, and the liquid phase contains a desulfurization agent with a mass ratio of 1.5%, and the composition of the desulfurization agent is CaO, CaCO 3 and MgO, whose mass ratio is CaO:CaCO 3 :MgO=1:1:0.5.

[0054] 2) Lime milk pre-aging + dynamic aging process...

Embodiment 2

[0069] The changes in this example are: the amount of sodium polyacrylate added in process 3) was changed to 0.2% of the mass of calcium carbonate, carbonization was carried out for 90 minutes until the pH value of the slurry reached 7.0, and carbonization was continued for 10 minutes; then calcium carbonate was added After whitening treatment (stirring for 60 minutes) with 2% by mass of whitening agent (sodium dithionite), 2% by mass of calcium carbonate modifier ammonium stearate was added through additive head tank 106d for wet modification (stirring for 60 minutes ), and then put into the cooked pulp tank to complete the carbonization process; other process steps are the same as

[0070] Example 1.

[0071] The performance test result of gained product calcium carbonate is shown in Table 1.

Embodiment 3

[0073] The changes in this example are: in step 3), add additive A sodium polyacrylate and additive B citrate with a theoretically generated calcium carbonate mass of 0.3% respectively, carbonize for 90 minutes until the pH value of the slurry reaches 7.0, and continue carbonizing for 30 minute. After adding whitening agent (sodium dithionite) with 2% calcium carbonate mass for whitening treatment (stirring for 60 minutes), in step 4) according to customer needs, the product is modified by dry method: calcium carbonate in cooked pulp tank 107 The slurry is sent to the plate and frame filter press 109 by the cooked pulp pump 108, dehydrated until the water content of the filter cake is 30% by mass, and the filter cake is sent by the belt conveyor 110 to the disc dryer 111 for drying until the water content by mass is less than 0.5% Finally, the calcium carbonate is sent into the kneader 112, and the modifier borate coupling agent (produced by Fujian Tianbao Plastic Co., Ltd.) i...

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Abstract

The invention discloses a precipitated calcium carbonate production technology for reducing magnesium and increasing calcium. The technology comprises the steps as follows: 1) a desulfurizing tower is serially connected with a washing tower in kiln gas purification, and a desulfurizer is added to a liquid phase of the desulfurizing tower, so that the purification effect of a kiln gas is improved, and meanwhile, the dosage of circulating water is reduced; 2) a raw slurry pre-ageing process and a dynamic ageing process are adopted, the "back-mixing" phenomenon is avoided, and the ageing time of the raw slurry is ensured; 3) a carbonation reaction kettle adopts a stirring apparatus with three layers of paddles, so that the carbonation reaction time is shortened, and the utilization rate of the kiln gas is increased; 4) magnesium is separated out from mother liquor from which calcium carbonate is separated out by adopting a steam pyrolysis method, filtrate is returned to a digestive process, and cyclic utilization of water is achieved. The precipitated calcium carbonate product obtained by the technology is small in grain size (D50 is approximate to 4mu), high in whiteness (greater than or equal to 94), low in magnesium content (MgO is smaller than or equal to 0.5%), and low in alkalinity (pH is smaller than or equal to 9), and is more applicable to the industries of plastic steel and the like with special demands on the magnesium content, the whiteness, the alkalinity and the like besides of meeting the industries such as rubber, plastic, papermaking and coatings.

Description

Technical field: [0001] The invention belongs to the field of inorganic materials, and relates to a new process for reducing magnesium and increasing calcium by using low-grade (especially high magnesium and iron content) limestone as raw material to prepare precipitated calcium carbonate. Background technique: [0002] As a high-quality filler and white pigment, calcium carbonate is widely used in industries such as rubber, plastics, paper, paint, ink, and medicine. [0003] Although our country is rich in limestone resources and widely distributed, the quality varies, which directly affects the quality of light calcium carbonate products. If the magnesium and iron content of limestone is too high, it will lead to high alkalinity, low whiteness and high magnesium content of calcium carbonate products. Adding it to plastic steel will lead to increased viscosity and increased tensile current, eventually resulting in plastic steel products. Yellowing and other consequences. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F11/18
Inventor 胡琳娜何豫基张广林解忠诚张东文费长荣赵朋伟
Owner 云南和铄投资管理有限公司
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