CN1865140A

CN1865140A - Nemalite carbonization for preparing light magnesium carbonate and high purity magnesia

Info

Publication number: CN1865140A
Application number: CN 200510072496
Authority: CN
Inventors: 王斌俊
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-05-19
Filing date: 2005-05-19
Publication date: 2006-11-22

Abstract

This invention discloses a method for producing lightweight magnesium carbonate and high-purity magnesium oxide by fibre brucite carbonization, comprising: a. disintegrate the fibre brucite, calcine at 500-600Deg C, add water to podzolizing, and send to the carbonization tower; b. CO2 enters the tower from the bottom, the pressure inside the tower is approximately 0.2-0.3Mpa, and the temperature is 25Deg C; c. after reaction matures, filtrate the heavy magnesium solution and heat it at 85-105Deg C to transform to basic magnesium carbonate; d. filtrate the solid basic magnesium carbonate, wash with deionized water, centrifuge to remove the water, and calcine in the rotary furnace at 600Deg C to produce the lightweight MgCO3; e. the MgCO3 can be transformed to high-purity MgO by calcining at 800-950Deg C, and after disintegration and product test, the product can be packed. The fibre brucite has little impurity and can produce MgO with 98.25% purity according to the said process.

Description

Carbonization of fiber brucite to prepare light magnesium carbonate and high purity magnesium oxide

Technical Field

The invention relates to a production method of light magnesium carbonate and high-purity magnesium oxide, in particular to a method for preparing light magnesium carbonate and high-purity magnesium oxide by using a fiber brucite raw material.

Background

Light MgCO₃Is an intermediate product for producing high-purity MgO, and the two are important raw materials in chemical industry and metallurgical industry. The current methods for producing MgO in China include a lime seawater method, a dolomite carbonization method, a magnesite soda ash method (ammonium bicarbonate method), a brine soda ash method and the like. These methods are either complicated in process or high in raw material cost. For example, 15-18 tons of brine and 3-3.5 tons of soda ash are needed for preparing one ton of MgO by using a brine soda ash method, and the cost for producing one ton of raw material is more than 8 thousand yuan.

Light MgCO₃Is a raw material of rubber, printing ink, ceramics, glass, cosmetics, toothpaste, etc. The melting point of the high-purity MgO is 2800 ℃ and the boiling point is 3600 ℃, and the MgO is a refractory material widely used in the metallurgical industry. According to nothingThe organic salt industry reports that: "the U.S. consumes over 100 million tons of MgO per year, and the ratio of U.S. MgO production to steel production is 7 kg/ton steel. The content of MgO popular in the world market is more than 95 percent ". According to HG1-324-77 standard, the high-purity MgO contains 98-99% of MgO, and the active MgO contains MgO: the special grade contains 95 percent of MgO, the first grade contains 93 percent of MgO and the second grade contains 92 percent of MgO. Light MgCO₃Special MgCO, also expressed in terms of MgO₃Contains 41-45% of MgO and primary MgCO₃Containing 41-45% of MgO and two-stage MgCO₃38-45% of MgO.

Survey of China non-metal mine industry (group) head office and geological sector: the asbestos mine in the southern Shaanxi province of Shaanxi province is the only mine enterprise for producing fiber brucite all over the world, and the proven storage capacity reaches 980 ten thousand tons. Is one of the 100 largest metal ore mining and selecting enterprises in China awarded by the State statistics Bureau. The asbestos mineral products mainly comprise three series of fibrobrucite, chrysotile and serpentine, wherein the fibrobrucite is taken as the main material, and the quality of the products is excellent. The enterprise has a history of 50 years, and no magnesium-making compound is found so far.

Disclosure of Invention

The invention aims to provide a method for preparing light magnesium carbonate and high-purity magnesium oxide by using fiber brucite as a raw material.

The technical scheme for realizing the purpose is as follows:

1. crushing fiber brucite, calcining at 500-600 deg.c to eliminate crystal water, adding water to incinerate, converting MgO into Mg (OH)₂I.e. Mg (OH)₂Sending the slurry into a carbonization tower for carbonization;

2、CO₂after dust-removing and water-washing, the mixture enters from the bottom of a carbonization tower, the pressure in the carbonization tower is about 0.2-0.3Mpa, the temperature is 25 ℃, and Mg (OH) is added₂Slurry in excess of CO₂Conversion to Mg (HCO) under the action of₃)₂The magnesium bicarbonate is heavy magnesium water in liquid phase, and the fiber brucite in the carbonization tower is about 10 percent of water or mother liquor;

3. after the reaction is mature, heavy magnesium water is filtered out and heated to 85-105 ℃ to be converted into basic magnesium carbonate，MgCO₃3H2O or XMgO YMg (OH)₂·ZH₂O；

4. Filtering solid basic magnesium carbonate, washing with deionized water, centrifuging, dewatering, and calcining at 600 deg.Cin converter to obtain light MgCO₃Testing and packaging the finished product;

5. light MgCO₃Calcining at 950 ℃ under 800 ℃ to obtain high-purity MgO, crushing, testing and packaging the finished product;

as the fibrous brucite contains less impurities, the MgO with the purity of 98.25 percent can be produced according to the process. The carbonization of fibrous brucite is used to prepare high-purity MgO, which only uses fibrous brucite and its leftover bits and dregs and then uses the waste gas CO from lime kiln₂The raw material cost is low when the carbonization is carried out in the carbonization tower.

Detailed Description

The present invention will be described in further detail with reference to the following examples:

1. the brucite is crushed and calcined at 500-600 deg.c to lose crystal water and obtain calcine, which is incinerated in water to convert MgO into Mg (OH)₂I.e. Mg (OH)₂Sending the slurry into a carbonization tower for carbonization;

2. the carbonization tower is made of 6mm steel plates, the diameter is about 1.4 meters, the height is 6-7 meters, and the inside and the outside are protected by epoxy resin. Exhaust gas CO of lime kiln₂The dust-removing and water-washing process is carried out, then the obtained product is fed from the bottom of the tower, the gas inlet main pipe is fed into the tower and is divided into 15-20 small nozzles, the nozzles are downward, the waste residue can not block the nozzles, the pressure in the carbonization tower is about 0.2-0.3Mpa (2-3at), and the temperature is 25 ℃; the cooling water pipe is added internally to reduce the temperature in summer;

3. the chemical reaction in the carbonization tower is Introducing excess CO₂Then is The magnesium bicarbonate is heavy magnesium water in liquid phase. The fiber brucite in the carbonization tower is about 10 percent of water or mother liquor;

4. after the reaction is mature, the heavy magnesium water is filtered out, and the slag is separated so as to ensureThe high purity of the heavy magnesium water can be centrifugally filtered, the heavy magnesium water is heated to 85-105 ℃ and is converted into basic magnesium carbonate, the molecular formula is different due to different operating conditions, and the heavy magnesium water is often expressed as MgCO₃3H2O or XMgO YMg (OH)₂·ZH₂O；

5. Filtering out solid basic magnesium carbonate, feeding mother liquor containing 0.5g magnesium salt into a sand baking pool to prepare Mg (OH)₂The slurry and the basic magnesium carbonate are washed by deionized water, centrifugally dewatered and calcined in a converter with the temperature of more than 600 ℃ to obtain the light MgCO₃Testing and packaging the finished product;

6. light MgCO₃CO decomposed by calcination at 800-950 DEG C₂Sending into a carbonization tower to obtain high-purity MgO, crushing by using a jet mill according to the requirement, and testing and packaging the finished product;

slag discharged from the carbonization tower is a good refractory material and a good heat-insulating material and needs to be researched and utilized.

The MgO is produced according to the process, and the three wastes and the toxicity are avoided.

The invention uses fiber brucite as a new raw material for preparing MgO for the first time. In practice there may be parameters to improve. Currently, there are dozens of magnesium compounds produced, especially for the production of MgCO₃And MgO has a great relationship with temperature and operating conditions, and parameters and operating processes need to be changed according to the requirements of users, so that the product is satisfied by the users.

Claims

A method for preparing light magnesium carbonate and high-purity magnesium oxide by a fiber brucite carbonization method is characterized by comprising the following steps:

a. crushing fiber brucite, calcining at 500-600 deg.c to eliminate crystal water, adding water to incinerate, converting MgO into Mg (OH)₂I.e. Mg (OH)₂Sending the slurry into a carbonization tower for carbonization;

b、CO₂after dust-removing and water-washing, the mixture enters from the bottom of a carbonization tower, the pressure in the carbonization tower is about 0.2-0.3Mpa, the temperature is 25 ℃, and Mg (OH) is added₂Slurry in excess of CO₂Conversion to Mg (HCO) under the action of₃)₂In the carbonization tower, the magnesium bicarbonate is heavy magnesium water in liquid phaseThe inner fiber brucite is about 10% of water or mother liquor;

c. filtering heavy magnesium water after the reaction is mature, heating the heavy magnesium water to 85-105 ℃ to convert the heavy magnesium water into basic magnesium carbonate MgCO₃3H2O or XMgO YMg (OH)₂·ZH₂O；

d. Filtering solid basic magnesium carbonate, washing with deionized water, centrifuging, dewatering, and calcining at 600 deg.C in converter to obtain light MgCO₃Testing andpackaging the finished product;

e. light MgCO₃Calcining at 950 deg.C under 800 deg.C to obtain high-purity MgO, pulverizing, testing and packaging.