Process for preparing calcined dolomite from magnesium chloride of chloride type by-product of potassium-extracting from salt lake

A technology of magnesium chloride and chloride, which is applied in the preparation of magnesium-calcium oxide for smelting magnesium by silicothermal method, and the production of calcined white for smelting magnesium by silicothermal method, which can solve the problems of endangering the safety of operators, environmental pollution, and high requirements for equipment corrosion resistance. problems, to achieve the effect of extending the industrial chain, abundant and easy-to-obtain raw materials, and simple and easy-to-control production process

Inactive Publication Date: 2009-01-07
QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This technology uses spray drying and calcining magnesium chloride to prepare metal magnesium. The process will produce a large amount of hydrogen chloride corrosive gas, which requires high corrosion resistance of equipment, and may cause environmental pollution and endanger the safety of operators.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] (1) Take 57.5g of ordinary construction lime calcined at 1200°C for 1.5 hours, add 460ml of water to prepare lime slurry, and the solid-to-liquid weight ratio of this slurry is 1:8.

[0034] (2) Measure 100ml of the saturated solution configured by the bischofite crystallized in the by-product mother liquor after extracting potassium from the salt lake, wherein the molar concentration of magnesium chloride is 4.7497mol / L.

[0035] (3) Add the prepared bischofite saturated solution into the prepared lime slurry to form a mixed system; stir for 10 minutes, and the mixed system slurry becomes viscous floc. In this mixing and system, the molar weight of CaO is 1.0268 moles, which is 2.16 times of the molar weight of magnesium chloride.

[0036] (4) Add polyacrylamide with 0.1% lime mass as a flocculant to the mixing system to flocculate the flocculent precipitate in the mixing system; then filter and separate, and wash the solid phase with 30ml of water for the separated so...

Embodiment 2

[0040] Get 57.5g of common building lime that has not been calcined, add water 460ml water and be mixed with lime slurry, all the other are identical in embodiment one.

[0041] In the synthesized calcined white, the molar ratio of MgO to CaO is 1:0.70 (less than 1:0.8). The water activity of synthetic calcined white is 23.52%.

[0042] Example 2 As a comparative example, we can see that lime is first calcined at 1000-1200° C. for 0.5-3 hours, preferably after 1.5-2 hours, and then mixed with water to make lime slurry, and then the by-product after extracting potassium from the salt lake The mixing of magnesium chloride raw materials is beneficial to increase the water activity of the synthetic calcined white and improve the molar ratio of MgO to CaO in the synthesized calcined white.

Embodiment 3

[0044] (1) Take 73.5g of ordinary building lime that has not been calcined, and add 588ml of water to prepare lime slurry. The solid-liquid weight ratio of this slurry is 1:8.

[0045] (2) Measure the old brine mother liquor (saturated magnesium chloride solution containing a small amount of sodium chloride and potassium chloride, wherein the molar concentration of magnesium chloride is 4.7068mol / L) by-product after extracting potassium from 100ml salt lake; join (1) step In the lime slurry prepared in , a mixed system is formed; after stirring for 30 minutes, the mixed system slurry becomes viscous floc. In this mixing and system, the molar weight of CaO is 1.3125 moles, which is 2.7885 times that of magnesium chloride.

[0046] (3) Add polyacrylamide with 0.2% lime mass as a flocculant to the mixing system to flocculate the flocculent precipitate in the mixing system; then filter and separate, and wash the solid phase with 30ml of water for the separated solid 3 Once, it is...

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PUM

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Abstract

The invention provides a method for preparing a composed calcined dolomite by taking the byproduct of brine ( a saturated liquor which is mainly magnesium chloride ) after potassium extraction or the bischofite separated out from the brine by naturally evaporating as the materials to react with excess lime to prepare the floccule mixture of magnesium hydrate and calcium hydroxide; then the mixture is calcined and dehydrated under the temperature of 400 to 1200 DEG C after the mixture is deposited, filtered, washed, dried and cracked. The materials of the invention are easily obtained and cheap; the production process is simply and easily controlled; no carbon dioxide is discharged; besides, the invention basically has no corrosion to a device. The mol ratio of MgO to CaO in the composed calcined dolomite is within the range of 1:0.8 to 1:1.2; the activity of water is 25 to 36 percent; the composed calcined dolomite is applicable for the areas rich in the resource of magnesium chloride to use a Pidgeon process to produce the metal of magnesium.

Description

technical field [0001] The invention belongs to the field of light metal smelting, and relates to a preparation method of magnesium-calcium oxide (commonly known as calcined white) for magnesium smelting by silicothermal method, in particular to a method of using magnesium chloride as a raw material, which is a by-product after potassium extraction from chloride salt lakes, through transformation, Calcination and other processes, the production of calcined white method for silicon thermal magnesium smelting. technical background [0002] The production methods of metal magnesium can be summarized into two methods, namely ferrosilicon thermal reduction method (Pidgeon method) and electrolysis method. The electrolytic method is to electrolyze molten anhydrous magnesium chloride to decompose it into metallic magnesium and chlorine gas. According to the raw materials used and the methods of processing raw materials, they can be subdivided into the following specific methods: Do...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B26/22
Inventor 龙光明何志贾优良祁米香
Owner QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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