Raw Materials of Magnesia Chrome Bricks

The raw materials for manufacturing magnesia chrome refractory are magnesia and chromite, and the main minerals are periclase and spinel. This type of high temperature fire brick has high refractory resistance, high high-temperature strength, strong resistance to alkaline slag erosion, excellent thermal stability, and certain adaptability to acidic slag. What’s more, the purity of magnesia raw materials should be as high as possible. The requirements for the chemical composition of chromite are: Cr₂O₃: 30~45%, CaO: ≤1.0~1.5%.

Classification and Uses of Magnesia Chrome Bricks

Generally speaking, in practical applications, we need to make a reasonable configuration of refractory fire bricks specification based on the kiln structure and working environment. The working principles of industrial kilns are different, and the types of magnesia-chromium bricks used are also different, so Kerui has produced various types of magnesia-chromium bricks for everyone to choose from. In addition to magnesia-chromium bricks, copper metallurgical hot kilns also use magnesia-chromium amorphous refractory materials such as magnesia-chromium ramming materials, magnesia fillers, and magnesia-chromium castables. If you want to buy refractory bricks, please contact Kerui.

Magnesia chrome bricks are generally divided into two types: unburnt mag chrome bricks and burnt mag chrome bricks. Burnt mag chrome bricks also have three types, they are common burnt mag chrome bricks, direct bonded mag chrome bricks and fused rebonded mag chrome bricks.

Unburnt Magnesia Chrome Bricks

Unburnt magnesia chrome bricks are made of high-quality magnesia and chromium ore, polyphosphate as the binding agent, and are made by high-pressure molding and low-temperature heat treatment. Compared with burnt magnesite chrome bricks, these wholesale fire bricks have a simplified manufacturing process and low cost. It also has high normal temperature compressive strength, low porosity and good thermal shock stability.

The polyphosphate chemical binder will completely decompose at about 1000℃. At this temperature, the medium and high-temperature structural strength of unburned mag chrome bricks is low. Therefore, the use effect is better in the firing zone of wet rotary kilns with frequent kiln shutdowns and low operating rates.

Burnt Magnesia Chrome Bricks

Generally, refractory bricks manufacturers produce four types of burned magnesia chrome bricks for everyone to choose from. They are common burnt magnesia chrome bricks, direct bonded magnesia chrome bricks, fused semi-rebonded magnesia chrome bricks and fused rebonded magnesia chrome bricks.

Common Burnt Magnesia Chrome Bricks

Common burnt mag chrome bricks are made of high-quality magnesia and chromium ore. The Cr₂O₃ content can be adjusted according to different needs, and the product has good thermal stability and high-temperature performance.

It is widely used in cement kilns, nonferrous metallurgical furnaces, etc.

Direct Bonded Magnesia Chrome Bricks

Direct bonded mag chrome bricks use chrome ore with low impurity content and high-quality high-purity mag as raw materials. It is formed by high pressure and fired at a high temperature of over 1,700℃. Therefore, these magnesia refractory bricks have good high-temperature performance, strong resistance to slag erosion, and resistance to cement clinker erosion.

The main applied working parts are: the bottom of the top-blown converter and the non-working layer of the furnace wall, the furnace wall of the Kifset furnace, the furnace wall of the Ausmet furnace, and the furnace top and furnace wall of the reverberatory furnace.

Fused Rebonded Magnesia Chrome Bricks

Fused rebonded mag chrome bricks are made by melting the raw materials into fused mag chrome materials using the electric fusion method, then crushing them into a certain particle size, and finally mixing, shaping and sintering. This industrial fire brick has a fine-grained texture with evenly distributed pores and micro cracks, and is more sensitive to sudden temperature changes than fused-cast bricks. In addition, the high-temperature performance of fused magnesia chrome bricks is between that of fused cast bricks and directly bonded bricks.

The main applied working parts are: the working layer of the top-blown converter furnace, the furnace mouth of the horizontal converter, the furnace mouth of the anode furnace, the furnace mouth of the electric furnace, the working layer at the bottom of the Kifset furnace, and the furnace wall of the Ausmet furnace and the bottom of the furnace and the lower part of the oxygen-rich bottom-blown slag line and the eye area.

Properties of Kerui Refractory’s Magnesia Chrome Bricks

The main crystal of mag chrome bricks is strongly alkaline periclase. Periclase has high density, low moisture, high molding pressure, low apparent porosity and high volume density. Therefore, these high performance magnesite bricks have the characteristics of multi-mineral composition, strong alkalinity and high density.

• Since mag chrome bricks are typical alkaline refractory materials, they have strong resistance to alkaline slag erosion.
• The melting point of periclase is as high as 2800℃, so the refractoriness of mag chrome bricks is also very high, generally up to more than 2000℃.
• The load softening temperature of mag chrome bricks is much lower than the refractory degree, which is about 1500℃.
• Mag chrome bricks have good thermal conductivity, but the thermal conductivity decreases significantly as the temperature increases. That is, mag chrome bricks have good thermal conductivity but low thermal insulation.
• Resistance to vacuum damage and resistance to oxidation and reduction are also two of the advantages of Kerui’s magnesia-chromium bricks.

Parameter Reference of Magnesia Chrome Bricks

Please refer to the table below to select the type of mag chrome brick you want. If you are not sure about the model of mag chrome bricks you want to buy, please contact Kerui, and Kerui’s business manager will help you find suitable magnesia chrome brick for sale.

Item/Grade		MGe-16A	MGe-16B	MGe-12A	MGe-12B	MGe-8A	MGe-8B
ω (MgO)/%	μ0 ≥	50	45	60	55	65	60
	ở	2.5
ω (Cr2O3)/%	μ0 ≥	16	16	12	12	8	8
	ở	1.5
Apparent Porosity/%	μ0 ≤	19	22	19	21	19	21
	ở	1.5
Cold Crushing Strength/MPa	μ0 ≥	35	25	35	30	35	30
	Xmin	30	20	30	25	30	25
	ở	15
0.2MPa Refractoriness Underload T0.6/℃	μ0 ≥	1650	1550	1650	1550	1650	1530
	ở	20

Principles of Excavation and Repair of Magnesia Chrome Bricks

Refractory bricks provide people with safety in the industrial field. At the same time, some refractory brick properties may be partially damaged due to the influence of external conditions. Then we need to maintain and repair these refractory bricks. Generally, we know that the refractory bricks required for industrial kiln production are mainly mag chrome bricks. The following are the precautions for excavation and repair of mag chrome bricks.

• Dig bricks from the weakest point of the brick, but you cannot dig more than three rings of bricks at the same time. If it is a continuous multi-ring excavation and filling, in order to prevent the entire brick from loosening, it is necessary to dig and mend 2 rings before continuing to dig and mend backward.
• When digging bricks, pay attention to the tightness of the entire ring of bricks. If the bricks are loose as a whole, stop digging and repairing immediately. Then use brick-locking iron plates to tighten the circumferential seams on both sides of the loose bricks. After tightening, confirm that they are not loose before continuing to dig and mend.

Reasons for Choosing Kerui

• Along-term service provider for Fortune 500 companies at home and abroad, and have rich experience in exporting products.
• Industry and trade integration. Kerui has our own production factory with guaranteed quality and stable supply capabilities.
• Kerui’s core technicians and engineers all have more than 20 years of experience in the refractory industry, so the manufacturing products are mature and highly professional.
• The employees are skilled and the production cycle is short. We will ship the goods on time within 7 days.
• One-stop customized production service. According to the actual situation of the customer, Kerui Group helps the customer choose the appropriate magnesia-chrome brick model.

Conclusion

If you are looking for a long-term and reliable magnesia chrome brick supplier, Kerui will be a good partner. We guarantee the quality of mag chrome bricks and have a complete pre-sales to after-sales service system. If you have questions about mag chrome bricks, please contact us on pinterest.  We will reply to you within 24 hours.