Method for duplex deposition of high-purity magnesium hydroxide by liquid ammonia-ammonia

A technology of magnesium hydroxide and ammonia water, applied in the direction of magnesium hydroxide, etc., can solve the problems of environmental pollution and high concentration of free ammonia, and achieve the effects of convenient process control, optimized reaction process, and convenient control

Inactive Publication Date: 2008-07-23
DALIAN MARITIME UNIVERSITY +1
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AI Technical Summary

Problems solved by technology

The concentration of free ammonia in the reaction system is high, which is easy to cause environmental pollution
There are reports on the preparation process of high-purity magnesium hydroxide, but its production process is intermittent, that is, the production process is

Method used

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  • Method for duplex deposition of high-purity magnesium hydroxide by liquid ammonia-ammonia

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Experimental program
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Effect test

Embodiment Construction

[0035] (1) preparation concentration is the magnesium chloride solution of 1mol / L:

[0036] Add bischofite to deionized water, stir at room temperature until completely dissolved, and prepare a magnesium chloride solution with a concentration of 1mol / L; use a centrifugal filter to filter the solution to remove impurities;

[0037] (2) Inject the reaction bottom solution

[0038] Inject 15 liters of deionized water into a reactor with an effective volume of 30 liters as the bottom liquid, add 100 g of seed crystals, heat to 85°C and keep it warm, and the temperature fluctuation range is less than ±10°C;

[0039] (3) Inject ammonia gas

[0040] Ammonia gas was continuously injected at a flow rate of 90 L / min. In the initial stage of the reaction, the ammonia gas is provided by liquid ammonia. After the reaction is started, the ammonia is provided by the ammonia water produced by the tail liquid treatment, and the liquid ammonia supplements the balance;

[0041] (4) inject mag...

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PUM

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Abstract

The invention provides a method for depositing highly pure magnesium hydroxide with a liquid ammonia-ammonia twofold-gang and relates to a method for continuously producing the highly pure magnesium hydroxide with a bischofite as raw material and ammonia and ammonia water as a precipitant. The treated bischofite is prepared into a solution with the concentration of 0.5 mol/L-4 mol/L, the precipitant is supplied by ammonia gas at the early stage of the reaction, then the precipitant is provided by the ammonia water reclaimed from the decomposition of the reaction product, ammonium chloride, the ammonia gas supplements the rest amount and the reaction process can be carried out continuously or intermittently. The method can be used for producing the magnesium hydroxide with the granularity of 10 microns-100 microns and the purity of 99 percent-99.999 percent. The product, ammonium chloride, adopts alkaline splitting and vacuum ejection flow to reclaim the ammonia gas, prepare the ammonia water for recycling utilization. The product produced by the invention has large granule size, high purity, more specifications, low cost, high equipment utilization rate, high reliability and stability of the technique, low one-time investment and has no pollution to the environment.

Description

technical field [0001] The invention belongs to the technical fields of metallurgy, inorganic non-metallic materials and chemical industry. Background technique [0002] At present, foreign countries use brine or seawater as raw material and milk of lime as precipitant to prepare magnesium hydroxide. In China, ammonia method is used to prepare magnesium hydroxide, but these research works cannot realize continuous production, or the purity of the product cannot reach the technical requirements. standard. The magnesium hydroxide product of this technology has large particles, high purity, and the continuous and intermittent production process can be randomly controlled. So far, no relevant literature reports with similar technical characteristics have been seen. [0003] Now the commonly used process of using bischofite as raw material to prepare magnesium hydroxide is summarized as follows: [0004] (1) Lime brine method [0005] with MgCl 2 ·6H 2 O is the raw material ...

Claims

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Application Information

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IPC IPC(8): C01F5/20
Inventor 徐久军王建力杜吉胜
Owner DALIAN MARITIME UNIVERSITY
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