40 Cold Crush Strength Direct-Bonded Magnesia-Chrome Brick for Temperature Refractory

 Magnesia-chrome bricks are refractory products containing magnesium oxide (MgO) and chromium oxide (Cr2O3) as the main components, and periclase and spinel are the main mineral components. This type of brick has high refractoriness, high temperature strength, strong resistance to alkaline slag, excellent thermal stability, and certain adaptability to acidic slag. The main raw materials for the manufacture of magnesia chrome bricks are sintered magnesia and chromite. The purity of the magnesia raw material should be as high as possible. The requirements for the chemical composition of the chromite ore are: Cr2O3: 30-45%, CaO: ≤ 1.0-1.5%.

Magnesia chrome brick • Instructions for use

Magnesia-chrome bricks are mainly used in metallurgical industries, such as the construction of open hearth furnace roofs, electric furnace tops, furnace refining furnaces, and various non-ferrous metal smelting furnaces. The high temperature part of the ultra high power electric furnace wall is made of fused cast magnesia chrome brick. The high erosive area of the refining furnace outside the furnace is made of magnesia chrome brick made of synthetic material. The high erosive area of nonferrous metal flash smelting furnace is made by melting cast magnesia chrome brick and synthetic material. Magnesia chrome bricks. In addition, magnesia-chrome bricks are also used in cement rotary kiln firing zones and glass kiln regenerators.

Magnesia chrome brick • production process

The production process of firing magnesia-chrome bricks is similar to that of magnesia bricks. In order to eliminate the brick during the firing process due to MgO and Cr2O3, Al2O3 or directly combined with magnesia chrome bricks

 The loosening effect caused by the expansion of iron oxides to form spinel can also be made into a magnesia chrome brick using a synthetic co-sintered material. In addition, there are non-calcined magnesia chrome bricks, for example, non-calcined magnesia chrome bricks combined with an inorganic magnesium salt solution. The non-burned magnesia chrome brick has a simple production process, low cost and good thermal stability, but the high temperature strength is far less than that of the fired brick. In the late 1950s, a so-called "direct combination" magnesia chrome brick was developed. The brick is characterized by pure raw materials, high firing temperature, direct combination of high temperature phases such as periclite and spinel, and low-melting phase such as silicate is island-like distribution, thus significantly increasing the high temperature of the brick. Strength and slag resistance.

 The method of preparing the fine powder prepared by calcining the calcined billet with chrome ore-magnesia sand and the coarse particles of magnesia is an effective measure for eliminating the loose effect. Compared with ordinary magnesia chrome bricks, the magnesia chrome bricks produced by this method have low porosity, high compressive strength, load softening temperature and flexural strength. Magnesia-chrome bricks made of chrome-magnesia powder compacts and high-temperature calcined synthetic magnesia-chrome sands are better than other magnesia-chrome bricks in slag resistance and high temperature strength.

 In addition, there is a molten cast magnesia chrome brick which is directly cast by using an electric orphan furnace molten magnesium chrome material, and a molten granule produced by the fused magnesia chrome material according to the brick making process and a magnesia chrome brick.

Material and performance index of magnesia chrome brick for cement kiln

After the Second World War, magnesia-chrome bricks began to replace the high-temperature belts of clay bricks and high-alumina bricks into cement rotary kiln. In China, the use of magnesia-chrome bricks is about 30 years later than abroad. In the early 1980s, a large number of chemically bonded unfired bricks were used. At about 1000 ° C, the bricks are weakened and damaged by the chemical bonding bonds due to the dissociation failure of the binder in the brick. Especially in the lower transition zone, the brick is peeled off thickly under the effect of reduction. At present, unburned bricks have been replaced by calcined magnesia chrome bricks in large precalciners.

Natural fused ore or its selected products and sintered magnesia made of natural or synthetic raw materials are the basic raw materials for the manufacture of magnesia chrome bricks. Ordinary magnesia chrome bricks or silicates combined with magnesia chrome bricks (containing 4% to 7% SiO2) combined with a lower melting point of the cinnamate phase (calcium-magnesium olivine CMS and magnesium-scruzzo C3MS2) combined with high refractory Magnesia and chrome, iron and aluminum composite magnesium spinel are formed, so it has high high temperature plasticity and microstructure toughness. It shows stress relaxation above 800 °C and good thermal shock stability. It is most suitable for 1000t. Used in small kiln below /d. However, its load softening temperature is low, and it is easy to be damaged by overheating, so it is rarely used in large precalcining kiln (≥4000t/d).

Magnesia-chrome bricks with low silicate content (including 2.5%~4% SiO2) still have certain microstructure toughness and high temperature stability, which is suitable for use in rotary kiln of 1500~4000t/d. It can also be used on both sides of the firing zone in the larger format rotary kiln. This brick can be referred to as a semi-direct combined magnesium chrome brick.

When the silicate content is extremely low (including 0.5%~2.5% SiO2), the periclase in the brick is directly combined with the composite spinel, and the high temperature resistance is greatly improved, but the microstructure toughness is very poor, to 1200. The stress relaxation in the brick lining occurs above °C, which seriously weakens the thermal shock stability, alkali corrosion resistance and resistance to oxidation-reduction atmosphere of the brick. This type of brick is called a direct combination of magnesia chrome bricks and is mainly used in the firing zone of large rotary kiln. However, this brick requires a pre-decomposed kiln cement clinker firing system to operate stably, and try to use raw materials and fuels with low alkali content to prolong its service life.

Transitional or extrapolated bricks may also be present between or outside of the above-mentioned magnesia chrome bricks. The series of magnesia chrome bricks have a SiO2 content of 7% to 6%, 4% to 2.5%, <2.5% to <1%, and 8% to 16% Cr2O3, 70% to 80% MgO, at normal temperature and high temperature strength. The thermal shock stability, thermal expansion coefficient, load softening temperature and other properties have corresponding changes to meet the different needs of the above various kiln. In recent years, under the urgent requirement of preventing chromium pollution, in industrialized countries, the use of dolomite bricks (and spinel bricks) in the firing zone, and the replacement of magnesia chrome bricks using spinel bricks in the transition zone are undergoing rapid changes. .

Packaging

1. 1 ton bags in container, 25 MT/20'FCL.
2. 25kg bags in container, 25 MT/20'FCL
3. 25kg bags in ton bags, then in container, 25 MT/20'FCL
4. as the customer' request

Packaging of SK37 High Alumina Refractory Brick

1.on wooden pallets with plastic cover: wooden pallet size :930*930 or 1000*1000mm,
2.Load weight of each pallet: 1.5-2.0 tons,

Shipping of SK37 High Alumina Refractory Brick

1.Our packaging is as per customer’s request
2.Normal goods delivered by sea transport
3.Sample shipping by express
4.We will shipping and delivery goods timely, quality and quantity guaranteed, and also in accordance with the contract and customer's requirement completely.

Delivery:

15-30 days working day for large quantity. The shipment we will arrange as soon as possible. Of course, if it is a custom products, the shipping time will delay.
Sample:

Usually by EMS, DHL, UPS, TNT, FedEx. Anyway you like. Bulk order: Usually by sea.

Payment:

It can be through T/T, L/C at sight. The specific terms determined according to the quantity of the goods, etc.
Your inquiry related to our product & price will be replied within 24 hours.
Export:
Our products have been exported to many countries: Australia, Chile, USA, Russia, UK, Indonesia, etc., good quality have be approved by our clients.

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Henan hongtai kiln refractory co., LTD. : "quality first, reputation first, customer first: it is our aim."Scientific management, strong technical force, perfect testing means, advanced technological equipment and stable product quality are the guarantee of quality service.Henan hongtai kiln refractories co., LTD sincerely hopes to cooperate with you hand in hand and in good faith.
Henan hongtai kiln refractory co., LTD. Main products are high alumina brick, clay brick, fused zirconium corundum brick, fireproof ball lightweight insulation brick, wear-resistant pouring material, corundum pouring material, low cement high strength pouring material, impermeable material, self-flowing material, plastic material, and various types of refractory materials.For different industries, the cement industry with anti-flaking high-alumina bricks, alkali resistant bricks, phosphate bricks;Boiler industry USES all kinds of brand wear-resisting brick, corundum brick, mullite brick and other finalizing materials.The company insists on "product quality is the life, enterprise integrity is the foundation", in the fierce market competition, won many users' trust and praise.The products are sold all over the country, as far as Vietnam, India, Korea, Pakistan, kazakhstan, other southeast Asian countries and regions.

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