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　　Xinmi, Henan, China is a gathering place for refractory materials. There are many manufacturers of refractory materials. Different manufacturers specialize in different fields. Regarding the manufacturers of refractory materials used in the cement industry, I recommend one to everyone - Zhengzhou Zhenjin Refractory Materials Co., Ltd.

　　Zhengzhou Zhenjin Refractory Materials Co., Ltd. has developed a series of high-end refractory materials for the cement industry to meet the needs of various refractory materials in the cement industry.

　　In addition, Zhenjin Refractory is the drafting unit for the new dry-process cement kiln magnesia iron spinel bricks and composite structure silica-molybdenum brick standards in China's refractory industry. The company has been awarded as a national "High-tech Enterprise", "Ministry of Industry and Information Technology Access Announcement Enterprise", and "Environmental Assessment Performance Compliance Level A" enterprise for 15 consecutive years; it has continuously passed ISO19001 quality management system, ISO24001 environmental management system and ISO45001 occupational health and safety management system certification.

　　The following lists 10 cement customer cases of Zhengzhou Zhenjin Refractory Materials Co., Ltd. and real customer feedback information. I hope it will be of reference value to you.

　　1. Zhangye Shandan Tieqi Cement Co., Ltd. 2500t/d cement line project

　　The overall quality of the products of Zhengzhou Zhenjin Company is excellent, and the safe operation and service life exceeds expectations. After the kiln was stopped, the overall bricks were inspected and the wear was not significant. The products of Zhengzhou Zhenjin Company are of high quality and are trustworthy refractory products.

　　2. Huaxin Cement (Huangshi) Co., Ltd. 10,000t/d cement line project

　　Zhengzhou Zhenjin's refractory brick products have good quality, regular appearance, good wear resistance and high cost performance. Their overall quality can completely replace imported products.

　　3. Ningxia Jinyuyuan Resource Recycling Co., Ltd.

　　Through the actual use of Zhengzhou Zhenjin Company's products, the raw materials used in the products have high purity, stable high-temperature performance indicators, high wear resistance, erosion resistance, and thermal shock stability. There is no erosion caused by spalling in the entire kiln system. Zhengzhou Zhenjin Company Jin Company's silicon-molybdenum wear-resistant bricks can meet our actual production needs, and our company's clinker production has achieved good economic benefits.

　　4. Zhejiang Haolong Building Materials Co., Ltd. 5000t/d cement line project

　　After our company uses the products of Zhengzhou Zhenjin Company, they have a long service life and good wear resistance, which have been highly praised by the company. We will continue to cooperate with Zhengzhou Zhenjin Company.

　　5. Chengde BBMG Cement Co., Ltd.

　　Zhengzhou Zhenjin Company's product quality and service are in good condition, with timely arrival and complete varieties. The engineering and technical personnel are serious and responsible. We are very satisfied with the overall service.

　　6. Dalian Tianrui Cement Co., Ltd. 5000t/d cement line project

　　The products of Zhengzhou Zhenjin Company comply with the relevant national technical requirements and meet the construction requirements well. The technical service attitude is good and can be adjusted in time according to the on-site construction conditions, which fully reflects the brand spirit of the company's products - real gold is not afraid of fire.

　　7. Linyi Zhonglian Cement Co., Ltd. 5000t/d cement line project

　　The company's 5000t/d production line uses Zhenjin Company's products. The company provides timely delivery and sends engineering and technical personnel to guide the masonry construction on site. The whole process is considerate and has received unanimous praise from our company. Because it saves time during the masonry construction, it ensures a smooth construction period. The completion provided good conditions, for which we are grateful.

　　8. Fujian Honghuo Cement Co., Ltd. 5000t/d cement line project

　　The products of Zhenjin Company are of good quality and service, and are deeply trusted by our company's leaders and employees. We will always choose the refractory materials products produced by Zhenjin Company and look forward to our long-term cooperation!

　　9. Anhui Wuhu Conch Cement Co., Ltd. 5000t/d cement line project

　　The overall quality of Zhenjin Company's products is excellent, and the service life can reach the expected time. After the kiln is stopped, the bricks are inspected after the kiln is stopped. The wear of the bricks is not great. Zhenjin Company's products are trustworthy refractory products.

　　10. Oriental Hope Chongqing Cement Co., Ltd. 5000t/d cement line project

Magnesia brick is a common refractory material consisting of magnesia and other additives. It has the following properties and uses:

Good high temperature performance: Magnesia bricks have excellent high temperature stability and fire resistance. It can maintain structural stability for a long time at extremely high temperatures, and exhibits a low coefficient of expansion and excellent thermal shock resistance.

Anti-corrosion performance: Magnesia bricks have high resistance to the erosion of acid, alkali and other chemical substances. This makes it widely used in corrosive environments in chemical, metallurgical and other fields.

Lightweight and high strength: Compared with traditional silicate bricks, magnesia bricks have lighter weight and higher strength. This makes it favored in applications where structural load relief is required or higher strength is required.

Good heat insulation performance: Since magnesia bricks have low thermal conductivity, it can provide good heat insulation performance, effectively reduce heat energy loss and save energy. Therefore, it is widely used in the heat insulation layer of kilns, furnaces and other high-temperature equipment.

Wide range of applications: Magnesia bricks are widely used in metallurgy, chemical industry, building materials, glass, ceramics and other industries. It is often used in the construction and protection of high-temperature equipment such as furnace lining, kiln insulation layer, refractory kiln wall, and glass kiln tunnel.

Magnesia chrome bricks use high-quality sintered magnesia and chromite (Cr203 30%-15%, CaO 1%-5%) as the main raw materials. The production process of magnesia-chrome bricks is roughly similar to that of magnesia bricks. Non-fired magnesia chrome bricks use inorganic magnesium salt solution as a binder. During the firing process, due to the loosening effect caused by the expansion of spinel when MgO reacts with CrO3, Al2O3 or iron oxides, pre-synthesized magnesia sand can be used to make bricks, which must be fired in an oxidizing atmosphere above 1600 ° C. become. If the nature of the atmosphere changes, Fe203 in chromite is affected by the redox reaction to form iron oxides of various valences. At the same time, Cr203 is also reduced to produce different valence compounds. Under repeated reactions, bricks will be damaged, so products with high MgO and low Cr2O3 should be used as much as possible.

According to the raw materials and process characteristics of the products, it can be divided into fused-cast magnesia-chrome bricks, directly bonded magnesia-chrome bricks, silicate-bonded magnesia-chrome bricks, rebonded magnesia-chrome bricks, semi-rebonded magnesia-chrome bricks, pre-reacted magnesia-chrome bricks and non-reactive magnesia-chrome bricks. Burnt magnesia chrome brick. The following is an introduction to the composition of different types of magnesia-chrome bricks:

Composition of fused cast magnesia-chrome bricks

Fused-cast magnesia-chrome bricks are refractory products made from magnesia and chrome ore through electric melting and casting. The production process of fused cast magnesia-chrome bricks is shown in Figure 1. It is characterized by large and isolated pores, dense products, high strength, corrosion resistance, and sensitivity to temperature changes. The chemical properties of magnesia-chrome bricks are alkaline. Compared with magnesia bricks and slabs, they have good thermal shock resistance, stable volume at high temperatures, and high load softening temperature.

Directly combine the components of magnesia-chrome bricks

Directly bonded magnesia-chrome bricks are made by combining sintered magnesia and chromite. It is required that the SiO2 content of the raw material is low, and it is fired at a high temperature above 1700 ° C to form a direct bond between periclase and chromite particles. The typical physical and chemical properties of directly bonded magnesia-chrome bricks are: MgO 82.61%, Cr2O3 8.72%, SiO2 2.02%, apparent porosity 15%, and bulk density 3.08g/cm3. The compressive strength is 59.8MPa, the load softening temperature is 1765°C, the thermal shock resistance is 1100°C (water-cooled) 14 times, and the flexural strength is 8.33MPa.

Composition of silicate-bonded magnesia-chrome bricks

Silicate-bonded magnesia-chrome bricks are made by sintering magnesia and chrome ore as raw materials, blending them in appropriate proportions and firing them at high temperature. The mineral composition of the product is periclase, spinel and a small amount of silicate. The production of silicate-bonded magnesia-chrome bricks uses brick-making magnesia and general refractory grade chrome ore as raw materials, Si02<4% in magnesia, Mg0>90%, Cr203 in chromium ore 32%-45%, and sulfite as the main material. After binder, kneading and forming, it is fired at about 1600°C. In order to prevent abnormal expansion of products during firing, a weak oxidizing atmosphere must be maintained in the kiln. The chemical composition of the product: Si02 2.98%-4.50%, MgO 61.75%-72.69%, Cr203 10.04%-14.90%. Physical properties: apparent porosity 18%-21%, normal temperature compressive strength 36.1-50.OMPa, load softening temperature 1600-1640℃.

Combining the composition of magnesia-chrome bricks

Recombined magnesia-chrome bricks are made by sintering fused magnesia-chrome sand as raw material. Fused magnesia-chrome sand has poor sinterability, and the product is a fine-grained matrix with uniform distribution of pores and tiny cracks. It is more sensitive to sudden temperature changes than fused cast bricks. The high-temperature performance of the product is between the fused cast brick and the direct bonded brick. The typical physical and chemical properties of combined magnesia-chrome bricks are: MgO 68%, Cr203 15%, SiO2 3%, apparent porosity 14%. Bulk density 3.20g/cm3, compressive strength 52.8MPa, load softening temperature 1740℃, flexural resistance Strength 7.86MPa.

Composition of semi-recombined magnesia-chrome bricks

Semi-recombined magnesia-chrome bricks are made from fused magnesia-chrome sand and magnesia, chromite or pre-reacted magnesia-chrome sand. The products have some characteristics of recombined magnesia-chrome bricks and directly combined magnesia-chrome bricks or pre-reaction magnesia-chrome bricks. The typical physical and chemical properties of semi-recombined magnesia-chrome bricks are: MgO 71.58%, Cr2O3 16.45%, SiO2 2.75%, apparent porosity 13%. Compressive strength 46.7MPa, load softening temperature 1760℃, flexural strength 9.09MPa.

Composition of pre-reaction magnesia-chrome bricks

What is a Magnesia brick?Magnesia brick is a refractory material mainly composed of magnesium oxide, which has the following uses:

1. Furnace lining: Magnesia bricks are widely used as lining materials for various industrial furnaces. Because magnesia bricks have excellent refractory performance and high temperature stability, and can withstand erosion and impact at extremely high temperatures, they are very suitable as protective materials for the inner wall of the furnace.

2. Starting plates and roofs: Magnesia bricks can also be used in the construction of starting plates and roofs. In the steelmaking and metallurgical industry, the high refractory performance and corrosion resistance of magnesia bricks make it an ideal material choice for the manufacture of starting plates and furnace roofs of blast furnaces, electric arc furnaces, converters and other equipment.

3. Glass kiln: Because magnesia bricks are less corrosive to glass melt and have good thermal conductivity and heat resistance, magnesia bricks are widely used in the inner lining and heat insulation layer of glass kilns. It can withstand thermal stress and thermal expansion under high temperature conditions, protect the kiln structure stability and provide good heat insulation effect.

4. Ladles, converters, electric arc furnaces: In the iron and steel industry, magnesia bricks are widely used in the lining of smelting equipment such as ladles, converters and electric arc furnaces. Magnesia bricks can withstand high temperature and erosion, and have good thermal conductivity and thermal expansion properties, suitable for environments that withstand high temperatures and chemical reactions during the smelting process.

5. Chemical equipment: Due to its excellent acid and alkali resistance, magnesia bricks are widely used in acid and alkali resistant linings and reactor linings in chemical equipment. It can resist the erosion and corrosion of chemical substances and ensure the stable operation of the device.

 Magnesia chrome brick is a high-quality refractory material composed of magnesium oxide (MgO) and chromium trioxide (Cr2O3). It has excellent performance in high temperature environment and is widely used in many fields. The following are the main uses of magnesia chrome bricks:

1、Metallurgical industry: Magnesia-chrome bricks are widely used in high-temperature equipment in the metallurgical industry, such as steel converters, electric furnaces, and smelting furnaces. They can be used in areas such as linings, furnace floors, furnace walls and furnace roofs to provide refractory protection and withstand erosion and wear under high temperature conditions.

2、Chlor-alkali industry: Equipment such as electrolyzers and evaporators in the production process of the chlor-alkali industry need materials that can withstand high temperatures and corrosion. Magnesia-chrome bricks are widely used in these equipment, providing excellent fire resistance and corrosion resistance, ensuring long-term stable operation of the equipment.

3、Oil refining and chemical industry: In the oil refining and chemical industry, magnesia-chrome bricks are often used in high-temperature equipment such as catalytic cracking units, hydrogenation units, reforming units and furnaces. They withstand high temperatures, corrosive gases and chemicals and provide reliable fire protection.

4、Glass industry: Glass furnaces are the core equipment in the glass industry, which are required to withstand extremely high temperatures and chemical erosion. Magnesia-chrome bricks are widely used in the inner lining, cooling zone and melting area of glass furnaces to maintain stable refractory performance and long service life.

5、Power industry: In the power industry, magnesia-chrome bricks are often used in high-temperature equipment such as boilers, burners, chimneys and hot blast stoves. They can withstand high temperature and flue gas erosion, and provide effective fire protection to ensure the normal operation and safety performance of equipment.

6、Other industries: In addition, magnesia-chrome bricks are also widely used in cement kilns, ceramic kilns, welding furnaces, carbonization furnaces, aluminum electrolytic cells and other fields. Its excellent fire resistance and corrosion resistance make it an important high temperature refractory material.

In conclusion, magnesia chrome bricks are widely used in several industries due to their high temperature resistance, erosion resistance and mechanical strength. Whether it is metallurgy, chlor-alkali, oil refining and chemical industry, glass or electric power and other fields, magnesia-chrome bricks can provide reliable fire-resistant protection to ensure long-term stable operation of equipment.

 Magnesia chrome brick is a high-quality refractory material composed of magnesium oxide (MgO) and chromium trioxide (Cr2O3). It has excellent performance in high temperature environment and is widely used in many fields. The following are the main uses of magnesia chrome bricks:

1、Metallurgical industry: Magnesia-chrome bricks are widely used in high-temperature equipment in the metallurgical industry, such as steel converters, electric furnaces, and smelting furnaces. They can be used in areas such as linings, furnace floors, furnace walls and furnace roofs to provide refractory protection and withstand erosion and wear under high temperature conditions.

2、Chlor-alkali industry: Equipment such as electrolyzers and evaporators in the production process of the chlor-alkali industry need materials that can withstand high temperatures and corrosion. Magnesia-chrome bricks are widely used in these equipment, providing excellent fire resistance and corrosion resistance, ensuring long-term stable operation of the equipment.

3、Oil refining and chemical industry: In the oil refining and chemical industry, magnesia-chrome bricks are often used in high-temperature equipment such as catalytic cracking units, hydrogenation units, reforming units and furnaces. They withstand high temperatures, corrosive gases and chemicals and provide reliable fire protection.

4、Glass industry: Glass furnaces are the core equipment in the glass industry, which are required to withstand extremely high temperatures and chemical erosion. Magnesia-chrome bricks are widely used in the inner lining, cooling zone and melting area of glass furnaces to maintain stable refractory performance and long service life.

5、Power industry: In the power industry, magnesia-chrome bricks are often used in high-temperature equipment such as boilers, burners, chimneys and hot blast stoves. They can withstand high temperature and flue gas erosion, and provide effective fire protection to ensure the normal operation and safety performance of equipment.

6、Other industries: In addition, magnesia-chrome bricks are also widely used in cement kilns, ceramic kilns, welding furnaces, carbonization furnaces, aluminum electrolytic cells and other fields. Its excellent fire resistance and corrosion resistance make it an important high temperature refractory material.

In conclusion, magnesia chrome bricks are widely used in several industries due to their high temperature resistance, erosion resistance and mechanical strength. Whether it is metallurgy, chlor-alkali, oil refining and chemical industry, glass or electric power and other fields, magnesia-chrome bricks can provide reliable fire-resistant protection to ensure long-term stable operation of equipment.

The main component of magnesia bricks is magnesia, and the main crystal is periclase, which accounts for 80%-90% of the mass of magnesia bricks. Its matrix compounds are magnesium ferrite, magnesium aluminum spinel, forsterite, calcium forsterite, etc.

一. Properties of magnesia bricks

Since the main crystal of magnesia brick is strongly alkaline periclase, it has high density, low water content, high molding pressure, low apparent porosity and high volume density. Therefore, magnesia bricks have the characteristics of multi-mineral composition, strong alkalinity and high density.

Magnesia brick is a typical alkaline refractory material, which has a strong ability to resist alkaline slag erosion.

The melting point of periclase is as high as 2800°C, so the refractoriness of magnesia bricks is also very high, generally above 2000°C.

The load softening temperature of magnesia bricks is much lower than the refractoriness, about 1500 ℃.

The thermal conductivity of magnesia bricks is good, but the thermal conductivity decreases significantly with the increase of temperature, that is, magnesia bricks have good thermal conductivity and low thermal insulation.

The thermal expansion of magnesia bricks is relatively large, and the linear expansion coefficient increases with the increase of temperature. The thermal shock stability of magnesia bricks is poor, and the number of water cooling is only 2-3 times.

二. the use of magnesia bricks

Magnesia chrome brick is composed of MgO55%80%, Cr2O38%20% partial alkali refractory thermal insulation materials crafts, with magnesia, compound spinel and a small amount of silicate phase. Compound spinel contains solid solutions of MgAl2O4, MgFe2O4, MgCr2O4 and FeAl2O4.

Magnesia chrome bricks in the 20th century after the 60 era because of the purity of raw materials and firing temperature to improve the rapid development trend, the current magnesia chrome bricks according to the different production methods can be divided into general bricks, immediate fusion bricks, mutual sintering bricks, refusion bricks and fused bricks.

(1) General magnesia-chrome brick

It is a traditional commodity, with chromium ore as coarse particulate matter and magnesia as fine powder. Or the two raw materials are composed of graded particles, and the firing temperature is generally 1550-1600 ° C. The microstructure of this kind of brick mainly shows that there is little immediate fusion between chromium ore particles and cubic magnesite, and more silicate (CMS) fine sand or crack protection. There is little dissolved phase in the cubic magnesite, very little immediate fusion in the cultivation medium, and this kind of brick has poor physical properties and poor slag corrosion resistance.

(2) Immediately fuse magnesia-chrome brick

Immediate fusion magnesia-chrome brick is in the general magnesia-chrome brick basic development trend, its production characteristics are key to two points, one is the selection of more pure raw materials, the second is the selection of higher firing temperature. In plain words, immediate fusion refers to the chromium ore particles in the brick and the cubic magnesite in the middle of more immediate contact, due to the raw material SiO2 less (manipulation in 1%25% below), the silicate generation is less, according to the high temperature firing method to make the silicate extrusion molding to the corner of the solid particles. This improves immediate solid phase fusion.

Immediate fusion magnesium-chrome brick because of the high level of immediate fusion, so that the brick has a high temperature compressive strength, slag resistance, corrosion resistance, erosion resistance, corrosion resistance and high-quality thermal shock reliability and volume reliability at 1800℃.

(3) mutually calcined magnesia-chrome bricks

The characteristics of this kind of handicraft production process is to burn the mixture of magnesia and chromium ore fine powder according to a certain preparation at high temperature, maintain the conversion into secondary spinel and magnesia-chromium ore immediate fusion for the purpose of solid phase reaction, prepare mutual calcined materials, and use this material to produce burnt products or organic chemical fusion crafts.

The immediate fusion and microstructure uniformity of intercalcined magnesia-chrome bricks are stronger than those of immediate fusion bricks, and there is a large amount of brucite dedissolved phase and intergranular secondary spinel. The intercalcined magnesia-chrome bricks have a series of stronger characteristics than immediate fusion bricks, especially famous for high temperature compressive strength, temperature resistance and slag resistance.

Mutual sintered bricks can be divided into two types, one is all mutual sintered bricks, particulate matter and fine powder new mutual calciners, whether fired or organic chemical fusion of their microstructure is mostly similar; The second is a part of the mutual sintering bricks, a part of the raw materials, such as coarse particles with mutual calcining materials, and a part of the fine powder can be mixed with fine chromium ore and magnesia paper powder according to a certain proportion of the brick, so that the fired and organic chemical fusion crafts will have a certain difference in microstructure.

(4) Re-fusion magnesia-chrome brick

Magnesia-chromium mixture particles are melted by electromelting tube method, and according to the crystallization of the solution, a raw material with a very symmetrical microstructure and composed of magnesia-chromium spinel and cubic magnesite mixed crystals as the key phase is produced. Such electromelting magnesia-chromium material is broken into a certain particle size distribution, mixed and formed, and fired to produce refused bricks, or immediately used as organic chemical junction bricks.

The microstructure of the refused brick is characterized by the immediate fusion of the aspect ratio and the presence of a lot of spinel dissolubilized phase: the base crystal with a lot of dissolubilized phase substantially changes the physical properties of the brucite, such as reducing the coefficient of linear expansion, improving the heat resistance, and improving the resistance to acid-alkali slag corrosion. The refused brick has similar characteristics to the actual application of fused cast brick, but has stronger temperature snap resistance and more symmetrical microstructure than fused cast brick.

The refused magnesium-chrome brick has a well-proportioned sand and gravel culture medium, and has fine cracks, and is more sensitive to sudden temperature changes than the fusion casting. The high temperature characteristics of handicrafts are close to the middle of fused cast bricks and immediately fused bricks.

(5) Cast magnesia-chrome brick

Magnesia and chromium mineral compounds are thoroughly melted in an electric arc furnace, and then the solution is forged into a fireproof casting mold. In the whole process of condensation, it is transformed into a smooth brucite and spinel crystal phase, and a fine crystal mechanism is produced, so the fused cast magnesia-chromium brick has excellent high temperature compressive strength and slag corrosion resistance.

Molten magnesium-chromium brick and electromolten magnesium-chromium material, with the height to width ratio of immediate fusion and with a lot of spinel dissolved phase, this kind of crafts caused by high relative density, slag is not easy to penetrate, so the slag resistance to improve the immediate fusion brick is stronger, but the heat resistance is worse than the two crafts.

common magnesia-chrome bricks include ordinary magnesia-chrome bricks, electro-fused rebonded magnesia-chrome bricks, direct-bonded magnesia-chrome bricks and sintered magnesia-chrome bricks. The main components are magnesia and chromium trioxide, which are characterized by high temperature strength and alkali resistance. Slag erosion ability is strong. The main crystal phase of magnesia-chrome bricks is mainly periclase and magnesia-chrome spinel.

First, the use of magnesia chrome bricks:

Magnesia chrome bricks are mainly used in the metallurgical industry, such as building open hearth furnace roofs, electric furnace roofs, refining furnaces outside furnaces and various non-ferrous metal smelting furnaces. The high-temperature part of the high-power electric furnace wall adopts fused-cast magnesia-chrome bricks, the high-erosion area of the refining furnace outside the furnace adopts magnesia-chrome bricks made of synthetic materials, and the high-erosion area of the non-ferrous metal flash smelting furnace is used.

Second, the characteristics of magnesia chrome bricks:

(1) High refractory temperature.

(2) The temperature of the 0.2MPA load softening edge is high.

(3) Strong resistance to alkaline slag.

(4) High temperature strength.

(5) Excellent volume stability at high temperature.

(6) The standard size is accurate and the construction is convenient, and the size can be processed according to the drawing.

There. Detection rules for magnesia chrome bricks：

1. The weight of each batch of bricks shall not exceed 100t.

2. Sampling and acceptance of bricks shall be carried out in accordance with YB 367-75 "Rules for Sampling, Acceptance, Storage and Transportation of Refractory Products".

3. Packaging, transportation, storage and quality certificate

4. The packaging, transportation and storage of bricks shall be carried out according to YB 367-75.

Magnesia-chrome bricks are refractory products composed of magnesium oxide (MgO) and chromium trioxide (Cr2O3) as the main components, and periclase and spinel as the main mineral components. They are alkaline refractory products. This type of brick has high refractoriness, high temperature strength, strong corrosion resistance to alkaline slag, excellent thermal stability, and certain adaptability to acid slag. Magnesia-chrome bricks are generally fired with lightly burned magnesia and imported chrome ore, also known as ordinary sintered magnesia-chrome bricks, or magnesia-chrome bricks for short. The firing process of magnesia-chrome bricks is roughly similar to that of magnesia bricks.

Magnesia chrome brick features: The refractoriness is greater than 2000°C, the softening temperature under load is generally above 1550°C, the high temperature volume stability is good, and the rapid cooling and heat resistance is good.

Magnesia chrome bricks are refractory products composed of magnesium oxide (MgO) and chromium trioxide (Cr2O3) as the main components, and periclase and spinel as the main mineral components. They are alkaline refractory products. This type of brick has high refractoriness, high temperature strength, strong corrosion resistance to alkaline slag, excellent thermal stability, and certain adaptability to acid slag. Magnesia-chrome bricks are generally fired with lightly burned magnesia and imported chrome ore, also known as ordinary sintered magnesia-chrome bricks, or magnesia-chrome bricks for short.

Sintered magnesia and fused magnesia with different MgO mass fractions (generally greater than 89%) are matched with refractory grade chromium ore, chrome concentrate, sintered or fused magnesia with different Cr2O3 mass fractions (sometimes adding a small amount Chrome green), producing many varieties of magnesium chrome products.

The most popular types of magnesia chrome bricks today are ordinary magnesia-chrome bricks, direct bonded magnesia-chrome bricks, recombined (semi-recombined) magnesia-chrome bricks and unfired magnesia-chrome bricks.

Ordinary magnesia chrome brick:

Ordinary magnesia-chrome bricks are generally produced from sintered magnesia (MgO mass fraction between 89% and 92%) and refractory grade chrome ore as raw materials. Due to the large amount of impurities, the refractory grains are bonded with silicate.

The magnesia-chrome bricks commonly referred to in China generally refer to fired ordinary magnesia-chrome bricks, also known as silicate-bonded magnesia-chrome bricks, or magnesia-chrome bricks for short.

Ordinary magnesia-chrome bricks have simple production process and low price, and are widely used in cement rotary kilns (Cr2O3 mass fraction rarely exceeds 14%), glass kiln regenerators, steelmaking furnace linings, permanent layers of refining ladles, nonferrous metallurgical furnaces, Lime kiln, mixed iron furnace and refractory high temperature kiln lining, etc.

Directly combined with magnesia-chrome bricks:

The main difference between the production process of directly combined magnesia-chrome bricks and ordinary magnesia-chrome bricks is that the former uses raw materials with less impurity content and is fired at a relatively high temperature.

For the production of magnesia directly combined with magnesia-chrome bricks, the mass fraction of MgO is generally greater than 95%, preferably greater than 97%, the particle volume density is about 3.25g/cm3, and the mass fraction of SiO2 in chrome ore is generally limited to below 3%. When using chrome concentrate, the SiO2 mass fraction can be lower than 1.0%.

According to different needs and uses, sometimes 1–2 kinds of magnesia and 1–2 kinds of chrome ore can be used for batching.

The cement kiln is directly bonded with magnesia-chrome bricks, generally magnesia is used as fine powder and part of the granular material, and chrome ore is used as the granular material, and the mass fraction of Cr2O3 is 3% to 14%;

The directly bonded magnesia-chrome brick used as a metallurgical furnace lining sometimes requires a Cr2O3 mass fraction as high as possible (such as 20%). When the purer magnesia and chrome ore co-ground fine powder are used as the matrix, the product often expands when fired.

Directly bonded magnesia-chrome bricks generally refer to products made of chrome ore with low impurity content and relatively pure magnesia, fired at a temperature above 1700 ° C, and the refractory grains are mostly in direct contact.

In the chemical composition of directly bonded magnesia-chrome bricks, there are few impurity components, and the direct bonding rate between refractory grains is high, so the slag resistance and high temperature performance are good.

Electrofusion recombination (semi-recombination) magnesia-chrome brick:

Usually people call the magnesia-chrome brick made of fused magnesia-chrome sand a rebonded magnesia-chrome brick, and the products that add part of fused magnesia-chrome sand are called semi-rebonded magnesia-chrome bricks.

Starting from the characteristic of direct combination of high-temperature crystal phase in microstructure, rebonded and semi-rebonded magnesia-chrome bricks are direct bonded bricks with higher direct bonding rate.

Due to the direct combination of magnesia-chrome bricks, recombined (semi-recombined) magnesia-chrome bricks have the characteristics of low impurity content and high-temperature (ultra-high temperature) firing, and these products are also called high-temperature fired (ultra-high temperature fired) magnesia-chrome bricks. brick.

The use of synthetic magnesia-chrome sand is the technological basis for the production of recombined and semi-recombined magnesia-chrome bricks.

Magnesia brick is a common refractory material, mainly made of light, high-purity magnesia raw materials. It has excellent high temperature resistance, thermal shock resistance, corrosion resistance and heat insulation performance, and is often used in high temperature equipment such as various industrial kilns and furnaces. Below are some of the main uses of magnesia bricks.

1. Uses in the iron and steel smelting industry: In the iron and steel smelting process, magnesia bricks are widely used in the lining and flue of converters, electric furnaces, heavy oil heating furnaces and other equipment to ensure the safe operation of the equipment.

2. Uses in the light metal smelting industry: Magnesia bricks are also widely used in the light metal smelting process, such as the lining and protection of aluminum electrolytic cells, aluminum alloy melting furnaces, magnesium alloy furnaces and other equipment.

3. Uses in the glass industry: Magnesia bricks are also used as linings and flues in kilns, crucibles and pipes in the glass industry to ensure the quality and efficiency of glass production.

4. Uses in the chemical industry: In the chemical industry, magnesia bricks can be used in equipment in high-temperature and high-corrosion environments such as sulfuric acid generation conversion furnaces and flue gas desulfurization equipment to improve their corrosion resistance and service life.

5. Other fields: Magnesia bricks are also widely used in mechanical processing equipment, oil drilling platforms and other industries that need to withstand high temperature and wear, so as to prolong the service life of the equipment.

One. The method of quickly judging the quality of refractory bricks

Intuitive method Just take out a few refractory bricks and observe the surface. There will be black spots on the surface of refractory bricks, which is unavoidable and a normal phenomenon. However, the more black spots on the surface of refractory bricks, the more impurities, the worse its quality and performance, the shorter the service life of the masonry refractory brick lining, and the shorter the time to replace the refractory bricks. Observe whether there are missing pieces on the edges and corners around the refractory bricks, and check whether there are cracks on the brick surface.

Touching method Touch the surface of the refractory brick directly to check whether it is rough. The surface of good refractory bricks feels smooth and flat, and the color is bright and evenly distributed, while the surface of poor-quality refractory bricks feels rough, slag-dropped, and the color is dull and unevenly distributed.

Weighing method Each refractory brick has a size. For example, the size of a standard refractory brick is 23011465mm. Refractory brick manufacturers provide physical and chemical indicators for each refractory brick, and check the volume density value. Multiply the bulk density by the refractory brick size to equal the weight of each refractory brick. Chongyang checks a few pieces, weighs them with an electronic scale, and checks whether they are qualified. the

Two. How to effectively identify the quality of refractory bricks

Look at the proportion of impurities in refractory bricks Generally speaking, impurities will be produced during the sintering process of refractory bricks strictly according to the proportion of ingredients, which is no problem. However, some manufacturers often do not produce according to the proportion of materials used, so that the sintered refractory bricks do not have a hard structure, so that the quality of the sintered bricks is not good enough, and then deceive consumers with high prices. Then when you buy refractory bricks, you can check it through its surface. Generally, the surface of refractory bricks with high impurity content will be very rough, while those refractory bricks that meet the quality standards have uniform overall color and smooth and flat surface, which we can intuitively distinguish from the surface.

Introduction of magnesia chrome brick: Magnesia-chrome bricks are refractory products with MgO and Cr2O3 as the main components, and periclase and spinel as the main mineral components. The main raw materials for manufacturing magnesia-chrome bricks are sintered magnesia and chromite. The purity of magnesia raw materials should be as high as possible. The chemical composition requirements of chromite are: Cr2O3: 30-45%, CaO: ≤1.0-1.5%. Zhengzhou Zhenjin Refractories Co., Ltd. is a manufacturing enterprise integrating R&D, production, sales and technical services. We are committed to the supply, construction and installation of refractory products in the cement, glass, building materials, non-ferrous smelting and metallurgical industries. .

Magnesia chrome brick features:

Magnesia-chrome bricks have high refractoriness and high temperature resistance

Strong resistance to alkaline slag erosion and excellent thermal shock stability

The production process of real gold magnesia chrome brick is simple and the service life is long

Magnesia chrome brick use: Magnesia-chrome bricks are mainly used in the cement industry and metallurgical industry, such as building open hearth furnace roofs, electric furnace roofs, refining furnaces outside furnaces and various non-ferrous metal smelting furnaces. The high-temperature part of the high-power electric furnace wall is widely used in fused cast magnesia-chrome bricks, the high-erosion area of the refining furnace outside the furnace is widely used in the high-erosion area made of synthetic materials, and the non-ferrous metal flash smelting furnace is widely used in high-erosion areas. Magnesia-chrome bricks made of materials. In addition, magnesia-chrome bricks are also widely used in the firing zone of cement rotary kiln and the regenerator of glass kiln.

The erosion of alkali and sulfur components and the phenomenon of rapid cooling and rapid heating aggravate the damage of refractory materials in the transition zone of cement rotary kiln. The real gold magnesia-aluminum spinel brick is made of high-quality high-purity magnesia and fused magnesia, and fused spinel is added. The magnesia-alumina spinel brick produced by a special process has excellent corrosion resistance and thermal shock resistance Stability is one of the refractory materials that can be selected under the adverse working conditions of large cement rotary kilns.

Through microscope observation, the magnesia-aluminum spinel bricks produced by Zhenjin Company have uniform distribution of particles, compact combination, high filling degree of the matrix part, good crystal phase combination, and a ring-shaped spinel structure is formed around the periclase particles.