CN1584076A

CN1584076A - Method for preparing magnesium with silica-alumina alloy as electronating agent

Info

Publication number: CN1584076A
Application number: CN 200410020666
Authority: CN
Inventors: 郭清富
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-06-04
Filing date: 2004-06-04
Publication date: 2005-02-23
Anticipated expiration: 2024-06-04
Also published as: CN1246487C

Abstract

A method for preparing magnesium with silica-alumina alloy as reducing agent includes: using dolomite and magnesite as raw materials, silica-alumina alloy as reducing agent, reducing calcined dolomite, and producing magnesium. Its technological process is: raw material->calcined dolomite and caustic magnesite->furnish->briquetting->grinding powder->vacuum reducing->magnesium, casting and magnesium ingot. Its furnish is: calcined dolomite (24%Mg), caustic magnesite (50%Mg). Its silica-alumina alloy component and preparation are: calcined dolomite: caustic magnesite: silica-alumina= 3.8-4.0: 0.8-1.2:1-1.4. It achieves low cost and high profit.

Description

Method for preparing magnesium metal by using silicon-aluminum alloy as reducing agent

Technical Field

The invention belongs to the technical field of metallurgy, and particularly relates to a method for preparing metal magnesium by taking silicon-aluminum alloy as a reducing agent.

Background

The silicothermic magnesium smelting method is the main method for producing metal magnesium at present, the method takes dolomite as raw material and takes ferrosilicon alloy as reducing agent, under the conditions of high temperature and vacuum, the dolomite is reduced and calcined to generate the metal magnesium, and the reduction reaction is as follows:

the general problems of the silicothermic method for preparing magnesium are as follows: the reduction temperature is as high as 1180-1250 ℃, the production period is as long as 12 hours, the briquetting pressure is large, and the briquetting pressure is generally 2000Kg/cm²The recovery rate of metal magnesium is low, the average recovery rate is only about 65%, the recovery rate is 15-20% lower than the world advanced technology, the energy consumption is high, the economic benefit is poor, the environmental pollution is serious, and the reduction slag is difficultTo be utilized, etc.

Disclosure of Invention

The invention aims to reduce and calcine dolomite and caustic magnesite to generate magnesium metal under the conditions of high temperature and vacuum by taking dolomite and magnesite as raw materials and taking silicon-aluminum alloy as a reducing agent, wherein the reduction reaction is as follows:

the production process flow of the invention is as follows: (the flow is shown in the attached drawing)

(1) Raw materials dolomite (13% Mg) and magnesite (28% Mg);

(2) calcining dolomite and magnesite at 1150 deg.C for 40 min in rotary kiln to obtain calcined dolomite and caustic

Magnesite, dolomitic (24% Mg), caustic magnesite (50% Mg);

(3) the ingredients calcined dolomite (24% Mg), caustic magnesite (50% Mg) and Si-Al alloy

(50-90%) Al + (10-50%) Si, and the furnace burden comprises the following components in percentage by weight: calcined dolomite, caustic magnesite and silica-alumina

The alloy is 3.8-4.0: 0.8-1.2: 1-1.4.

(4) Briquetting and briquetting machine for briquetting, the pressure is 300-500 Kg/cm²；

(5) The milled powder is milled by a milling ball mill, and 100 percent of a 100# sieve passes through the milled powder;

(6) the temperature of the vacuum reduction furnace is 1000-1150 ℃, and the reduction time is 6-8 hours;

(7) metal magnesium, casting, magnesium ingot.

The invention has the advantages that: when the method is implemented according to the process conditions, compared with a silicon thermal method, the method has the following good effects: the yield is increased by 1-1.4 times, the energy consumption is reduced by more than 50%, the cost of the metal magnesium is reduced by 20-25%, the equipment investment is reduced by 40-60%, the consumption of the reduction tank is reduced by 55%, and the profit is increased by about 7 times.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The production is as in the example:

if the market price of the metal magnesium is 15000 yuan per ton, the cost of magnesium per ton in a silicothermic magnesium plant with the annual output of 2240 tons is as high as 13870 yuan, and the annual profit is only (15000-13870) ═ 25312 ten thousand yuan, if the silicothermic magnesium plant is changed into a thermal magnesium plant of silicon-aluminum alloy, the economic benefit is very obvious due to the superior process conditions, and the details are shown in the table below.

Comparison of silicoaluminothermic and silicothermic annual yield, product cost and annual profit

Production method	Silicothermic process	Silicoaluminothermic process
Production method	Silicothermic process	Silicoaluminothermic process			Alloy composition	75％Si+25％Fe	60％Al+40％Si	70％Al+30％Si	85.263％Al+14.737％Si
Annual output in tons	2240	4898	5138	5541	Alloy composition	75％Si+25％Fe	60％Al+40％Si	70％Al+30％Si	85.263％Al+14.737％Si
Annual output in tons	2240	4898	5138	5541	Ton of magnesium cost, Yuan	13870	11044	10908	10705
Annual profit, ten thousand yuan	253	1938	2103	2380	Ton of magnesium cost, Yuan	13870	11044	10908	10705

Due to the increase of the yield, the product cost is reduced, and the annual profit is increased by 6-8 times.

The following three examples were carried out under the above-mentioned process conditions, composition of the raw materials and the reducing agent

(coal as fuel in vacuum reductionfurnace)

Example 1:

the furnace burden proportion is as follows: 2100 kg of calcined dolomite, 500kg of caustic magnesite,

600 kg of silicon-aluminum alloy (60% of Al and 40% of Si);

the implementation conditions are as follows: briquetting in a briquetting and briquetting machine under the pressure of 300-500 Kg/cm²；

The milled powder is milled by a milling ball mill, and 100 percent of a 100# sieve passes through the milled powder;

the temperature of the vacuum reduction furnace is 1000-1150 ℃, and the reduction time is 6-8 hours;

the implementation results are as follows: the magnesium yield is 667 kg, and the magnesium metal recovery rate is 84%.

Example 2:

600 kg of silicon-aluminum alloy (70% of Al and 30% of Si);

the implementation conditions are as follows: the same as above;

the implementation results are as follows: the magnesium yield is 674 kg, and the recovery rate of metal magnesium is 84%.

Example 3:

600 kg of silicon-aluminum alloy (85.263% Al + 14.737% Si);

the implementation conditions are as follows: the same as above;

the implementation results are as follows: the magnesium yield is 710.6 kg, and the recovery rate of metal magnesium is 88.36%.

Claims

1. A method for preparing magnesium metal by taking silicon-aluminum alloy as a reducing agent is characterized in that dolomite and magnesite are taken as raw materials, silicon-aluminum alloy is taken as the reducing agent, the dolomite and caustic magnesite are reduced and calcined under the conditions of high temperature and vacuum to generate magnesium metal, and the reduction reaction is as follows:

；

the method comprises the following process flows:

(1) raw materials dolomite (13% Mg) and magnesite (28% Mg);

Magnesite, dolomitic (24% Mg), caustic magnesite (50% Mg);

(3) burdening calcined dolomite (24% Mg), caustic magnesite (50% Mg) and silicon-aluminum alloy;

(7) metal magnesium, casting, magnesium ingot.

2. The method for preparing magnesium metal by using silicon-aluminum alloy as a reducing agent according to claim 1, wherein the reducing agent comprises: silicon-aluminum alloy components: (50-90%) Al + (10-50%) Si.

3. The method for preparing metal magnesium by using silicon-aluminum alloy as a reducing agent according to claim 1, which is characterized in that the charge mixture ratio is as follows: calcined dolomite, caustic magnesite and silicon-aluminum alloy are 3.8-4.0: 0.8-1.2: 1-1.4.