Precipitated calcium carbonate production technology for reducing magnesium and increasing calcium

A technology of precipitating calcium carbonate and production process, applied in the direction of calcium carbonate/strontium/barium, etc., to achieve the effect of improving purification effect, high mass transfer efficiency and improving quality

Inactive Publication Date: 2014-06-25
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

Method used

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  • Precipitated calcium carbonate production technology for reducing magnesium and increasing calcium
  • Precipitated calcium carbonate production technology for reducing magnesium and increasing calcium
  • Precipitated calcium carbonate production technology for reducing magnesium and increasing calcium

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0049] Example 1:

[0050] The process flow of this embodiment is:

[0051] 1) Kiln gas purification process

[0052] The kiln gas produced by lime kiln 5 (see "Inorganic Salt Technology", Zhou Youying. Chemical Industry Press, page 168) is passed into the lower part of desulfurization tower 101, and the desulfurized kiln gas flows out from the top of desulfurization tower 101, and then enters the scrubber The lower part of the tower 102 flows out from the top of the scrubbing tower 102 (at this time the temperature of the kiln gas drops to 40°C, CO 2 The volume content of kiln gas is 30%), and enters the gas-liquid separator 103; after the liquid droplets are separated by the vapor-liquid separator 103, the kiln gas is sent to the bottom of the carbonization tower 105 by the Roots blower 104.

[0053] Among them, the liquid phase in the desulfurization tower is water, and the liquid phase contains a desulfurizer with a mass ratio of 1.5%. The composition of the desulfurizer is CaO an...

Example Embodiment

[0068] Example 2:

[0069] The changes in this embodiment are: the amount of sodium polyacrylate added in step 3) is changed to 0.2% of the mass of calcium carbonate, the carbonization reaction is 90 minutes until the pH of the slurry reaches 7.0, and the carbonization is continued for 10 minutes; then calcium carbonate is added After whitening treatment with 2% mass of brightener (sodium dithionite) (stirring for 60 minutes), add calcium carbonate mass 2% modifier ammonium stearate through the additive high tank 106d for wet modification (stirring for 60 minutes) ), then put it into the cooking tank to complete the carbonization process; other process steps are the same

[0070] Example 1.

[0071] The performance test results of the obtained product calcium carbonate are shown in Table 1.

Example Embodiment

[0072] Example 3:

[0073] The changes in this embodiment are: in step 3), the additive A sodium polyacrylate and the additive B citrate are respectively added with 0.3% of the theoretically generated calcium carbonate mass, and the carbonization reaction is 90 minutes until the pH value of the slurry reaches 7.0, and the carbonization is continued for 30 minute. After adding a whitening agent (sodium dithionite) of 2% calcium carbonate mass for whitening treatment (mixing for 60 minutes), in step 4), the product is dry modified according to customer needs: calcium carbonate in the cooked slurry tank 107 The slurry is sent to the plate and frame filter press 109 by the cooked slurry pump 108, and is dehydrated until the water content of the filter cake is 30% by mass. The filter cake is sent to the disc dryer 111 by the belt conveyor 110 and dried until the water content is less than 0.5%. Then, the calcium carbonate is fed into the kneader 112, and the modifier borate coupling ...

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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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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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