Process for smelting magnesium by alumino-thermic reduction of magnesia

A process method, magnesium oxide technology, applied in magnesium oxide and other directions, can solve problems such as waste of resources and energy

Inactive Publication Date: 2005-09-07
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In order to solve the deficiencies of the above Pidgeon method for smelting magnesium, the object of the present invention provides a kind of processing method of thermally reducing magnesium oxide, utilizes the original equipment of Pidgeon method and adopts reducing agent aluminum to contain magnesium oxide minerals (dolomite, magnesite Magnesium and brucite) as raw materials, effectively solve the problem of waste of resources and energy

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Example 1: Magnesium smelting by reduction of calcined dolomite by thermite method

[0020] The chemical formula of dolomite is MgCO 3 .CaCO 3 . Dolomite contains 21.8% MgO and 30.4% CaO, the rest is CO 2 . MgO and CaO in dolomite fluctuate and also contain impurities.

[0021] Dolomite undergoes the following chemical reactions after calcination:

[0022] (1)

[0023] The MgO.CaO produced by this reaction is called calcined dolomite (commonly known as calcined white).

[0024] The chemical reaction of thermal reduction of MgO.CaO with aluminum (Al) as reducing agent is shown in (2).

[0025] (2)

[0026] The content of MgO and CaO in calcined dolomite fluctuates, that is, the content of MgO and CaO is sometimes higher than the theoretical value, sometimes lower than the theoretical value. When the content of MgO in calcined dolomite is high, CaO needs to be added, and when the content of CaO is high, MgO needs to ...

Embodiment 2

[0027] Embodiment 2: Reduction of calcined magnesite by thermite method for smelting magnesium

[0028] The chemical formula of magnesite is MgCO 3 . Magnesite contains 47.82% MgO, 52.18CO 2 . Calcined MgCO 3 The decomposition reaction is as follows:

[0029] (3)

[0030] In fact, MgO in magnesite is fluctuating and also contains impurities. When reducing calcined magnesite to smelt magnesium by thermite method, CaO (lime) needs to be supplemented to meet the requirements of chemical reaction formula (2).

[0031] The proportioning ratio of magnesite, limestone and aluminum is 3-6:2-3:0.8-1.5 respectively. Mixed magnesite and limestone calcined or separately calcined, powder milled, added aluminum powder ingredients, agglomerated (pressure 20-40Mpa), reduced magnesium. The reduction period is 8 hours, the reduction temperature is 1100-1150°C, and the vacuum degree is 1-23.3Pa.

Embodiment 3

[0032] Embodiment 3: Reduction of calcined brucite to smelt magnesium by thermite method

[0033] The chemical formula of brucite is Mg(OH) 2. Theoretically, brucite contains 69.13% MgO. The decomposition reaction during calcination is as follows:

[0034]

[0035] MgO in brucite is fluctuating and also contains impurities. When reducing calcined brucite to smelt magnesium by the thermite method, CaO (lime) needs to be supplemented to meet the requirements of chemical reaction formula (2).

[0036] The batching ratios of brucite, limestone and aluminum are respectively: 2-6:2-6:0.8-1.5. Brucite and limestone are mixed and calcined or calcined separately, pulverized, aluminum powder is added, pellets are made (pressure 20-40Mpa), and magnesium is reduced. The reduction period is 8 hours, the reduction temperature is 1100-1150°C, and the vacuum degree is 1-23.3Pa.

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PUM

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Abstract

The invention relates to an extraction method of nonferrous metal magnesium, in which dolostone(MgCO3, CaCO3), brucite (Mg(OH)2) and giobertite (MgOCO3) are chosen as raw material, metal aluminum as reducer. At first, said three raw materials are calcined respectively to produce magnesia. Magnesia reacts with reducer aluminum with chemical reaction formula: 21MgO+12CaO+14Al=12CaO.7Al2O3+21Mg, in which weight of each raw material accords to reaction formula. Raw materials are mixed, forced to ball and then added into reduction jar. Reduction jar is added into reduction furnace. Advantages of the invention: saving 20-50% of energy cost and increasing service life of reduction jar; reducing periodic time of reduction from 12h to 7-8h so as to increase output of single jar; increasing 30-90% of magnesium production; decreasing racial of raw material and magnesium; furnace slag having multiple use and reducing cost of magnesium manufacture.

Description

technical field [0001] The invention relates to a method for extracting nonferrous metal magnesium. Background technique [0002] At present, the main minerals containing magnesium oxide used in thermal magnesium smelting are magnesite (the main chemical composition is MgCO 3 ) Dolomite (MgCO 3 , CaCO 3 ) and brucite (Mg(OH) 2 ). Among them, the Pidgeon method is widely used at home and abroad, that is, calcined dolomite (MgO, CaO) is used as raw material and ferrosilicon (Si-Fe) is used as reducing agent to smelt magnesium. The advantage of using the Pidgeon method to smelt magnesium is that the method is simple and has been used for a long time, but its disadvantages are: high energy consumption, 13 tons of coal per ton of magnesium, and the cost of coal is also rising, the reduction cycle and reduction time Long time (10-12 hours), the amount of magnesium produced per unit is not high, and each reduction tank can produce about 30Kg of magnesium. The biggest disadvant...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F1/00C01F5/06C22B26/22
Inventor 路忠胜
Owner NORTHEASTERN UNIV
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