Method for producing magnesium hydroxide from mixed solution containing magnesium chloride and calcium chloride by lime seeding method

A magnesium hydroxide and mixed solution technology, applied in the direction of magnesium hydroxide, calcium/strontium/barium chloride, calcium/strontium/barium halide, etc., can solve the problem of low value and no economy of magnesium chloride and calcium chloride mixture problems, to achieve the effect of small investment, easy operation and low production cost

Inactive Publication Date: 2014-04-30
江苏仁欣化工股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Direct evaporation and crystallization, the obtained mixture of magnesium chloride and calcium chloride has low value and is not economical

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Magnesium chloride, calcium chloride mixed solution 1m 3 , and its chemical composition is as follows:

[0021] pH

Mg g / L

Ca g / L

8.5

10

39.8

[0022] will be 1m 3 Fill the mixed solution of magnesium chloride and calcium chloride into 2m 3 In the stirring tank, add 0.5kg of industrial magnesium hydroxide seed crystals (the amount of seed crystals added is 0.05 of the magnesium metal content of the mixed solution of magnesium chloride and calcium chloride), stir for 10 minutes, raise the temperature to 30°C, and add effective CaO10% lime milk 233kg, continue to stir for 1h after adding, the pH of the end point of magnesium precipitation is 9.0, and the material after precipitation of magnesium hydroxide is obtained.

[0023] The material after the precipitated magnesium hydroxide is filtered with a filter area of ​​4m 2 The chamber filter press is filtered, and the filter cake is washed with 49 kg of water on the filter press, a...

Embodiment 2

[0030] Magnesium chloride, calcium chloride mixed solution 5m 3 , and its chemical composition is as follows:

[0031] pH

[0032] will be 5m 3 Fill the mixed solution of magnesium chloride and calcium chloride into 20m 3 In the stirring tank, add 4.2 kg of magnesium hydroxide produced in Example 1 (dry weight, the amount of seed crystals added is 0.02 of the magnesium metal content of the mixed solution of magnesium chloride and calcium chloride), stir for 10 minutes, heat up to 60 ° C, and use 1 ton Add 2.45t of milk of lime with effective CaO20% at a speed of 1 / h, and continue stirring for 3 hours after the addition is complete, the pH of the magnesium precipitation end point is 10.0, and the material after precipitation of magnesium hydroxide is obtained.

[0033] The material after the precipitated magnesium hydroxide is filtered with an area of ​​80m 2 The chamber filter press is filtered, and the filter cake is washed with 49 kg of water on the filter press...

Embodiment 3

[0041] Magnesium chloride, calcium chloride mixed solution 5m 3 , and its chemical composition is as follows:

[0042] pH

Mg g / L

Ca g / L

7.2

24

26

[0043] will be 5m 3 Fill the mixed solution of magnesium chloride and calcium chloride into 20m 3 In the stirring tank, add 12 kg of magnesium hydroxide produced in Example 2 (dry weight, the amount of seed crystals added is 0.03 of the amount of magnesium metal in the mixed solution of magnesium chloride and calcium chloride), stir for 10 minutes, heat up to 45 ° C, and use 1 t / Add 2.8t of milk of lime with 10% effective CaO at a speed of h, and continue to stir for 2 hours after the addition is complete. The final pH of magnesium precipitation is 9.5, and the material after precipitation of magnesium hydroxide is obtained.

[0044] The material after the precipitated magnesium hydroxide is filtered with an area of ​​80m 2 The chamber filter press is filtered, and the filter cake is wash...

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PUM

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Abstract

The invention discloses a method for producing magnesium hydroxide from a mixed solution containing magnesium chloride and calcium chloride by a lime seeding method. The method is capable of producing high-purity magnesium hydroxide through the steps of adding the magnesium hydroxide to the mixed solution containing magnesium chloride and calcium chloride, stirring and then slowly adding lime milk, wherein the produced high-purity magnesium hydroxide is good in filtration performance, easy to wash and capable of completely separating calcium from magnesium. The calcium chloride solution left after the magnesium hydroxide precipitates can be used for producing crystalline calcium chloride through evaporative crystallization. The method is changeable in production scale, wide in application, simple in process route, low in investment, low in energy consumption, free of pollution to environment, good in calcium-magnesium separation effect, simple and convenient to operate and low in production cost; and therefore, a quite effective, economical and practicable way is provided for producing the magnesium hydroxide from the mixed solution of magnesium chloride and calcium chloride.

Description

technical field [0001] The invention relates to a method for producing magnesium hydroxide by a lime seed crystal method in a mixed solution containing magnesium chloride and calcium chloride, and belongs to the field of resource recovery and utilization. Background technique [0002] In the chemical production process, when acid and alkali are neutralized, a large amount of mixed solution of magnesium chloride and calcium chloride will be produced. The solution after stirring and leaching of laterite nickel ore with hydrochloric acid, calcium carbonate iron removal, and nickel precipitation with lime is also a mixed solution of magnesium chloride and calcium chloride. It is difficult to separate the mixed solution of magnesium chloride and calcium chloride. Direct evaporative crystallization, the value of the obtained magnesium chloride, calcium chloride mixture is low, not economical. [0003] In order to reduce the impact of the discharge of the mixed solution containing...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F5/22C01F11/28
Inventor 江山柯鼎王泽强
Owner 江苏仁欣化工股份有限公司
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