Aluminothermic reduction method and technology of giobertite calcination to produce magnesium

A technology for calcining magnesite and magnesite powder, which is applied in the field of extraction of aluminum reduction metals and magnesium, can solve the problems of low slag value, long reduction period, and decreased activity of MgO, and achieve shortened reduction time, which is beneficial to environmental protection, The effect of reducing the amount of processing

Inactive Publication Date: 2006-02-08
路忠胜
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the Pidgeon method also has the following disadvantages: the reduction temperature is high, so the energy consumption is high (~13 tons of coal / ton of magnesium); the reduction period is long (12 hours), and the production efficiency is low; the output of single tank magnesium is low (~30Kg / ton) times), the daily output is low; the amount of slag is relatively large (~7 tons of slag / ton of magnesium), and the value of slag is low
And in calcined dolomite MgCO 3 ·CaCO 3 , due to CaCO 3 The decomposition needs to be heated to 1200 ° C, and at this temperature, MgCO 3 The activity of the decomposed MgO has decreased significantly, so calcining dolomite to produce magnesium consumes energy but does not achieve good results, which is not worth the gain.

Method used

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  • Aluminothermic reduction method and technology of giobertite calcination to produce magnesium
  • Aluminothermic reduction method and technology of giobertite calcination to produce magnesium
  • Aluminothermic reduction method and technology of giobertite calcination to produce magnesium

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Effect test

Embodiment 1

[0042] Raw material handling:

[0043] Magnesite (MgCO 3 ) after coarse crushing and medium crushing to a particle size of 0.25mm, calcined at 700°C for 1 hour to make active MgO, and then finely ground and sieved for later use; then limestone (CaCO 3 ) into a powder with a particle size of 0.833 mm, and then calcined at 1100° C. for 1 hour to make CaO powder, and then finely ground and sieved for later use.

[0044] Ingredients Briquette:

[0045] The calcined and sieved fine powder of MgO and CaO and aluminum powder are evenly mixed according to weight percentage: 80:5:15, and then pressed under a press at a pressure of 40 MPa to form agglomerates.

[0046] Reduction of magnesium:

[0047] Put the pressed agglomerate in the reaction tank of Pidgeon method, then put the reaction tank into the heating furnace (reduction furnace), evacuate to 1 Pa, heat to 1050°C, and react for 8 hours to obtain crude magnesium.

Embodiment 2

[0049] Raw material handling:

[0050] Firstly, the magnesite is crushed to a particle size of 0.075mm through primary crushing and secondary crushing, and then calcined at 1000°C for 1 hour to make active MgO, which is finely ground and sieved for later use; then the limestone is crushed by the same process and calcined at 1100°C for 1 hour hour to make CaO powder with a particle size of 0.075mm, and sieve it for later use.

[0051] Ingredients Briquette:

[0052] The calcined and sieved fine powders of MgO and CaO and aluminum powder were uniformly mixed in a weight percentage of 35:15:54, and then pressed under a press at a pressure of 450 MPa to form agglomerates.

[0053] Reduction of magnesium:

[0054] Put the pressed agglomerate in the reaction tank of Pidgeon method, then send the reaction tank into the heating furnace, vacuumize to 13.3 Pa for heating, keep the temperature at 1170°C for 4 hours, and reduce to obtain crude magnesium.

Embodiment 3

[0056] Raw material handling:

[0057] First, the magnesite is crushed to a particle size of 0.15mm through primary crushing and secondary crushing, and then calcined at 900°C for 1 hour to make active MgO, which is then finely ground and sieved for use; then the limestone is crushed to a particle size of 0.25mm by the same process The powder was then calcined at 1150°C for 1 hour to make CaO, which was finely ground and sieved for later use.

[0058] Ingredients Briquette:

[0059] The calcined and sieved MgO, CaO powder and aluminum powder were evenly mixed according to the weight percentage of 65.64:5.07:29.28, and then pressed under a press at a pressure of 300 MPa to form agglomerates.

[0060] Reduction of magnesium:

[0061] Put the pressed agglomerate in the reaction tank of Pidgeon method, then put the reaction tank into the reduction furnace, evacuate to 2 Pa, and react at 1150°C for 6 hours to make crude magnesium.

[0062] In a word, because the present inventio...

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Abstract

Disclosed is an aluminothermic reduction method and technology of giobertite calcination to produce magnesium which comprises using magnesite powder as raw material, aluminum powder as reducing agent, the invention is characterized in that, (1) charging 5-15 wt% calcined limestone powder (CaO) as adjuvant, (2) calcining magnesite powder at 700-1000 deg C for 1 hour to prepare active MgO, (3) mixing magnesite powder, limestone powder and aluminum powder by the weight ratio of 35-80:5-15:15-54, making into blocks under 40-450MPa, (4) loading the block into retort, evacuating and heating in reducing furnace, reducing 4-8 hours at 1050-1170 deg. C to obtain crude magnesium. The invention also discloses the optimum parameter for the process.

Description

technical field [0001] The invention belongs to the technical field of metal reduction by aluminum and extraction of magnesium, and relates to a process for smelting magnesium by the aluminothermic method. Background technique [0002] At present, magnesium production methods are divided into two categories, magnesium chloride molten salt electrolysis method and thermal reduction method. The electrolysis method consumes too much energy and causes serious environmental pollution, so it has been seldom used by people. The most widely used thermal reduction method is the Pidgeon method, that is, the calcined dolomite (MgO CaO) is used as the raw material and the ferrosilicon (Si-Fe) is used as the reducing agent. Under certain conditions, the reaction produces metallic magnesium. However, the Pidgeon method also has the following disadvantages: the reduction temperature is high, so the energy consumption is high (~13 tons of coal / ton of magnesium); the reduction period is long...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B26/22C22B1/16C22B5/04
Inventor 路忠胜
Owner 路忠胜
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