CN1281499C - Process for producing high purity magnesia - Google Patents

Abstract

The present invention discloses a method which has the advantages of simple equipment, easy operation, continuous production and low production cost and is used for producing a high purity magnesia product. Bittern containing magnesium chloride in a sea and a lake, or coarse magnesium chloride hexahydrate is used by the present invention as a raw material, the bittern is purified by a vacuum crystallization method, and boron, sulfate radicals, calcium ions, and other soluble impurities in the raw material are removed; then, the bittern is dynamically calcined, high purity magnesia (MgO is greater than 99%) serial products and hydrochloric acid (30%) can be produced by technology. The method has the characteristics of short technical line, little investment, simple equipment, easy operation, continuous production, low cost, etc.; the method can produce the high purity magnesia serial products and the hydrochloric acid. The technology carries out closed cycle production, and has the advantages of cleanness and environmental protection.

Description

The production method of high-purity magnesium oxide

Technical field

The present invention relates to the technical field of marine chemical industry in the inorganic chemical engineering, in particular, the bittern that relates to utilize ocean, salt lake to contain magnesium chloride is the method for raw material production high-purity magnesium oxide, highly pure active magnesium oxide, highly-purity magnesite and hydrochloric acid.

Background technology

The high-purity magnesium oxide series product are magnesium salts fine chemical products, be widely used in Iron And Steel Industry, rubber, senior cable, senior plastics, paint, pottery, senior papermaking and pharmaceutical industries, the high-purity magnesium oxide more than 99% is produced the best industrial chemicals of oriented silicon steel sheet especially.Highly-purity magnesite is the main raw material of the used high-grade refractory brick carbon magnesia brick of metallurgy, Cement industry

Produce magnesian raw material at present in the world and mainly be divided into two kinds: first kind of solid mineral feedstock such as the rhombspar, magnesite that high pollution is arranged for under-developed country's multi-tool produced the magnesium oxide of 93-97%; The seawater that another kind is used for west advanced country more, the above high-purity magnesium oxide of the 96%-99% that bittern is produced.

China is three magnesium salts big producing countries in the world, but is not power.Because for a long time, it is raw material that solid ore deposits such as magnesite, rhombspar are mainly adopted in the magnesium oxide production of China, the magnesium oxide quality of producing is lower, though introducing external sophisticated equipment in recent years increases, but still be lower than 96% based on purity, be difficult to reach high-purity requirement, more can't satisfy domestic year 100000 tons demand.Though the scientific payoffs of meticulous magnesium oxide product is continuous in recent years, kind, quantitatively still can not satisfy the demand in market, let alone export trade, because meticulous magnesium oxide product is few, also had a strong impact on the magnesium salts economic benefit of enterprises.As about 8000 yuan of common light calcined magnesia domestic prices, and silicon steel level magnesium oxide reaches 20,000 yuan, and high-purity magnesium oxide (＞99%) is more than 30,000 yuan.So promote the structural adjustment of magnesium industry, accelerate the research and development of China's magnesium salts product innovation, producing functional magnesium products has become the task of top priority.At present, it is blank that the production of domestic high-purity magnesium oxide also belongs to basically, magnesium be product functionalization, customizations, becoming more meticulous becomes the emphasis of countries in the world research and development.

Because domestic to produce purity of magnesite low, so the furnace life of carbon magnesia brick in steel melting furnace of the production of using is generally at the 300-400 stove.And use highly-purity magnesite (content is more than 99%) to reach the 4000-5000 stove abroad for the raw material made furnace life of carbon magnesia brick in steel melting furnace, and not only improve furnace life greatly, and can also satisfy the needs that special steel is produced, huge economic benefit is arranged.China does not still have the high-purity electrosmelted magnesite clinker of manufacturer production at present, thereby need spend a large amount of foreign exchange imports (about 100,000 tons of existing annual imports), and China produces steel big country, output of steel has reached more than 1.1 hundreds of millions tons, need 10 kilograms of highly-purity magnesites to calculate by steel per ton, only China needs about 1,100,000 tons of highly-purity magnesite in static market year.And China is again magnesium resource big country, production cost hangs down and also has competitive power in the international market, present China's magnesium salts and magnesium oxide factory 33 families, the low-grade magnesian outlet every year of producing all more than 1,300,000 tons, and high-grade high-purity magnesium oxide, highly-purity magnesite etc. are again by import, so the high-grade magnesian production of development China will have great economic and social benefit.

Our traditional technology is difficult to take part in international competition because scientific and technological content is lower at present.The present domestic lime that is just using (or rhombspar) method, carborization energy consumption height not only also is difficult to solve the calcium contents problem that exceeds standard; Domestic advanced ammonia process and carbon ammonia method technology, though these methods can both be produced high-grade magnesium oxide product, but still have several problems: promptly magnesium oxide and magnesiumcarbonate all will be dissolved in the ammonia solution, keep this balance and will constantly carry out replenishing of ammonia, there is pollution problem, during by magnesium hydroxide and magnesiumcarbonate system magnesia, all wants pressure ball or moulding dead roasting afterwards, this has just caused the too high and operational difficulty of energy consumption, and sad cost closes.

A lot of in the world now national with bittern method production magnesium oxide and magnesium hydroxide, but its impurity removal process is very complicated, as: need to use the calcium chloride sulfate radical, use ion exchange method attracts boron etc.This has not only prolonged operational path, has introduced new calcium impurities simultaneously again.This method need be carried out three calcinings, and easy dust from flying again when middle product magnesium hydroxide is carried out dead roasting causes damage and pollutes, so need pressure ball or moulding again, has increased facility investment and production cycle.

After sea, the purification of earning of lake bittern water process, its major ingredient is a magnesium chloride hexahydrate, and magnesium chloride hexahydrate promptly generates magnesium oxide and hydrogen chloride gas through high-temperature calcination, and hydrogen chloride gas absorbs through water can produce hydrochloric acid.Magnesium oxide can produce high-purity magnesium oxide, highly pure active magnesium oxide and highly-purity magnesite respectively according to different calcining temperatures.

Summary of the invention

The objective of the invention is in order to overcome the deficiencies in the prior art, provide that a kind of equipment is simple, processing ease, can continuous production and the method for the low production high-purity magnesium oxide product of production cost.

The present invention produces the method for high-purity magnesium oxide product, is achieved by following technical proposals, comprises the steps:

1. vacuum-evaporation: old halogen is evaporated under vacuum tightness 0.06-0.07MPa, 120 ℃ of conditions of temperature;

2. settlement separate: as in the insulation settling vessel, to carry out 105 ℃ of its holding temperatures; Be interrupted when producing soaking time 3 hours;

3. spray pyrolysis: the high density material dissolution liquid with above-mentioned, carry out 280～320 ℃ of temperature in the dynamic pyrolysis stove with Sprayable; Pyrolysis time 3-6 second;

4. dynamic calcining: with the basic magnesium chloride superfine powder of gained behind the spray pyrolysis, enter again in the high temperature dynamic calcining stove and calcine, 600～650 ℃ or 700 ℃ of calcining temperatures; Distinguish calcination time 5-10 second;

5. pulverize washing: the thick magnesium oxide powder after the calcining, in pulverizing washing machine, to pulverize, wash, solid-to-liquid ratio was controlled at 1.3: 10;

6. expansion drying: will dewater through the magnesium oxide solid after the washing, in flash distillation dryer, carry out drying afterwards and can become high-purity magnesium oxide.

The present invention provides a kind of utilization sea, lake bittern water or thick magnesium chloride hexahydrate and is raw material, utilize the vacuum crystallization method that bittern is purified boron, sulfate radical, calcium ion and other soluble impurity of removing in the raw material, calcine the Technology that to produce high-purity magnesium oxide series product and hydrochloric acid then.This method compares with other existing method that the route that possesses skills is short, equipment simple, processing ease, can continuous production, production cost is low and can produce characteristics such as high-purity magnesium oxide series product and hydrochloric acid.Raw brine is produced high-purity serial magnesium oxide (magnesium oxide＞99%), and does not have the three wastes, and is free from environmental pollution, accomplishes cleaner production.

Embodiment

Below in conjunction with embodiment the present invention is described further.

Embodiment 1:

A. vacuum-evaporation: with the vacuum-evaporation under vacuum tightness 0.06-0.07MPa, 120 ℃ of conditions of temperature of old halogen;

B. settlement separate: as in the insulation settling vessel of 105 ℃ of temperature, to be incubated sedimentation 3 hours, clear liquid is carried out crystallisation by cooling in crystallizer, 30-40 ℃ of crystallization final temperature;

C. spray pyrolysis: the high density purification of raw materials liquid with above-mentioned, carry out pyrolysis with Sprayable, about 300 ℃ of temperature, reaction times 3-6 second in the dynamic pyrolysis stove;

D. dynamic calcining: with the basic magnesium chloride superfine powder of gained behind the spray pyrolysis, enter in the high temperature dynamic calcining stove again and calcine, calcination time 5-10 second, the control calcining temperature can obtain thick magnesium oxide powder for 600-650 ℃;

E. pulverize washing: the thick magnesium oxide powder after the calcining, in pulverizing washing machine, to pulverize, wash, solid-to-liquid ratio was controlled at 1.3: 10;

F. dry: as will to carry out centrifuge dehydration through the magnesium oxide solid after the washing, and in flash distillation dryer, carry out drying afterwards and can become highly pure active magnesium oxide;

G. hydrochloric acid absorbs: the hydrochloric acid gas in the furnace gas absorbs with water cycle in the absorption tower after the cyclonic separation dedusting, can produce the hydrochloric acid of different stage after the purification.

Embodiment 2:

1. vacuum-evaporation: with the vacuum-evaporation under vacuum tightness 0.06MPa, 120 ℃ of conditions of temperature of old halogen;

2. settlement separate: as in the insulation settling vessel, to carry out 105 ℃ of its holding temperatures;

3. spray pyrolysis: the high density stock liquid with above-mentioned, carry out about 300 ℃ of temperature, reaction times 3-6 second in the dynamic pyrolysis stove with Sprayable;

4. dynamic calcining: with the basic magnesium chloride superfine powder of gained behind the spray pyrolysis, enter in the high temperature dynamic calcining stove again and calcine, about 700 ℃ of control calcining temperatures, can obtain thick magnesium oxide powder at the equal 5-10 of calcination time second;

5. pulverize washing; Thick magnesium oxide powder after the calcining is pulverized, is washed in pulverizing washing machine, and solid-to-liquid ratio was controlled at 1.3: 10;

6. dry: as will to carry out centrifuge dehydration through the magnesium oxide solid after the washing, and in moisture eliminator, carry out drying afterwards and can become high-purity magnesium oxide;

7. high-purity magnesium oxide is through high-temperature calcination in electric arc furnace, and temperature 2800--3000 ~ C can produce high-purity electrosmelted magnesite clinker in 6--8 hour;

8. hydrochloric acid absorbs: the hydrochloric acid gas in the furnace gas absorbs with water cycle in the absorption tower after the cyclonic separation dedusting, can produce the hydrochloric acid of different stage after the purification.

Claims (1)

1, a kind of production method of high-purity magnesium oxide is characterized in that, comprises the steps:

1. vacuum-evaporation: Jiang Hai, the vacuum-evaporation under vacuum tightness 0.06MPa, 120 ℃ of conditions of temperature of the old halogen in lake;

2. settlement separate: carry out in the insulation settling vessel, 105 ℃ of its holding temperatures are interrupted when producing soaking time 3 hours;

3. spray pyrolysis: the high density stock liquid with above-mentioned, carry out 280～320 ℃ of temperature, pyrolysis time 3-6 second in the dynamic pyrolysis stove with Sprayable;

4. dynamic calcining: the alkali formula magnesium oxide superfine powder with gained behind the spray pyrolysis enters in the high temperature dynamic calcining stove again and calcines, about 600-650 ℃ or 700 ℃ of control calcining temperature, calcination time 5-10 second respectively;

5. pulverize washing: the thick magnesium oxide powder after the calcining, in pulverizing washing machine, to pulverize, wash, solid-to-liquid ratio was controlled at 1.3: 10;

6. expansion drying: will dewater through the magnesium oxide solid after the washing, in moisture eliminator, carry out drying afterwards and can become high-purity magnesium oxide.