A kind of method that uses low-grade magnesite to prepare magnesium oxide raw material and low particle size magnesium hydroxide

A technology of magnesium hydroxide and magnesium oxide, applied in the production of magnesium hydroxide and lime, which can solve the problems of long washing cycle, numerous process steps, small magnesium hydroxide, etc.

Active Publication Date: 2017-05-03
刘昕
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method has disadvantages such as low yield and long washing cycle, and it is impossible to produce magnesium hydroxide with a small particle size.
Concentrated seawater extraction method, which uses concentrated seawater to extract slurry-like magnesium hydroxide, in which the existence of calcium ions is an important factor affecting the purity and quality of the product, and there are also problems of many impurities and large particle sizes
Another method is to prepare magnesium hydroxide by hydrating magnesium oxide, but this method currently has problems such as low magnesium hydroxide hydration ratio, large particle size of magnesium hydroxide, and numerous process steps.

Method used

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  • A kind of method that uses low-grade magnesite to prepare magnesium oxide raw material and low particle size magnesium hydroxide
  • A kind of method that uses low-grade magnesite to prepare magnesium oxide raw material and low particle size magnesium hydroxide
  • A kind of method that uses low-grade magnesite to prepare magnesium oxide raw material and low particle size magnesium hydroxide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Magnesium oxide with a measured calcium sulfate content of 0.61% by mass, produced from bischofite, was used. According to the ratio shown in Table 1, magnesium oxide, distilled water and barium chloride (with no addition of barium chloride as a control) were added and placed in a reaction kettle in a water bath at 50°C, stirred at a speed of 400 rpm for 6 hours, passed The liquid was filtered off by suction to obtain crude magnesium hydroxide. Then dry to constant weight (moisture content is lower than 1% by weight) at 50 ℃, make dry magnesium hydroxide, use 100 micron mesh sieve to sieve off residue, obtain final magnesium hydroxide product, and according to HG / The method described in T 3607-2007 (issued on April 13, 2007, implemented on October 1, 2007) measures D50. The results are shown in Table 1 below as well as figure 1 middle.

[0048] Table 1

[0049] Barium Chloride: Calcium Sulfate Molar Ratio D50(micron) 1 12.0 2 1.4 3 1.3 ...

Embodiment 2

[0052] Example 2 was carried out in the same manner as in Example except for the contents shown in Table 2 below.

[0053] Table 2

[0054] Barium Chloride: Calcium Sulfate Molar Ratio D50(micron) 2.0 1.41 2.1 1 2.2 0.82 2.3 0.51 2.4 0.53 2.5 0.57 2.6 0.61 2.7 0.69 2.8 0.78 2.9 0.88 3.0 1.32 3.1 1.34 3.2 1.33 3.3 1.35 3.4 1.46 3.5 1.47 3.6 1.42 3.7 1.38 3.8 1.52 3.9 1.58 4.0 1.6

[0055] From figure 2 combined with the results in Table 2 figure 1 It can be seen from the results that in figure 1 In the flat section where the molar ratio of barium chloride and calcium sulfate is 2:1 to 4:1, there is actually a "deep pit" between the molar ratio of 2.3:1 and 2.9:1. The D50 can be stably in the range of 0.5 to 1.0 micron, and a magnesium hydroxide product with a smaller particle size can be obtained by adopting the molar ratio in this range.

Embodiment 3

[0057] Example 3 was carried out in the same manner as in Example 1 except for the contents described in Table 3 below. See Table 3 below for the results.

[0058] table 3

[0059]

[0060]

[0061] Note:

[0062] (1)*The mass fraction of the sieve residue refers to the mass percentage of the material that does not pass through the 75-micron mesh when sieving with a 75-micron test sieve to the entire material.

[0063] (2) The mass fraction of sieve residue and D50 are carried out according to the method stipulated in the industry standard of HG / T 3607-2007 (issued on April 13, 2007, implemented on October 1, 2007), and the mass fraction of sieve residue is class II The standards for first-class products and qualified products are less than or equal to 0.02% and less than or equal to 0.05% respectively; the standards for Class III first-class products and qualified products are respectively less than or equal to 0.5 and less than or equal to 1.0. The D50 Class I stand...

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Abstract

The invention provides a preparation method for a magnesium oxide raw material and magnesium hydroxide with low particle size by using low-grade magnesite. Specifically, the invention provides a preparation method for a magnesium oxide raw material used for producing magnesium hydroxide by using low-grade magnesite. The method comprises the following steps: subjecting magnesite to calcining so as to obtain light calcined ore, and recycling carbon dioxide; crushing the light calcined ore, and preparing the crushed light calcined ore into a slurry with a concentration of 35%; subjecting the slurry and an ammonium chloride solution to reaction, then filtering the reacted slurry, and recycling ammonia gas; subjecting obtained filtrate, ammonia water and carbon dioxide to reaction, and carrying out filtering; subjecting the filtrate and excess ammonia water to reaction, then carrying out filtering, washing filter residue, and carrying out drying so as to obtain crude magnesium oxide; and detecting the content of calcium sulfate, and adding barium chloride so as to obtain the magnesium oxide raw material. The invention also provides a preparation method for magnesium hydroxide by using the magnesium oxide raw material. According to the invention, the low-grade magnesite can be utilized to prepare magnesium hydroxide with high hydration rate and D50 less than 1.0 micron.

Description

technical field [0001] The invention relates to a method for preparing magnesium oxide raw material and magnesium hydroxide with low particle size by using low-grade magnesite. Background technique [0002] Although my country's natural magnesite resources are very rich, after decades of mining, commercial-grade magnesite has become less and less, especially high-grade magnesite can no longer meet production needs in some areas. However, low-grade magnesite cannot be directly used in the production of high-grade products, especially a large amount of extra-grade magnesite cannot be utilized, resulting in a waste of magnesite resources. Therefore, considering long-term interests, in order to better utilize resources, how to make full use of low-grade magnesite to solve the problems of low utilization rate of magnesite resources and shortage of high-grade magnesite is a very important issue in this field. . [0003] Magnesium hydroxide is also called caustic magnesia, light ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B2/10C01F5/16
CPCC01F5/16C01P2004/61C01P2004/62C04B2/10Y02P40/40
Inventor 姚胜铎
Owner 刘昕
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