Magnesia carbon brick: an excellent representative of high performance refractory materials

 

In many fields of modern industrial production, the operation of equipment in high temperature environments faces severe challenges, and refractory materials have become a key factor in ensuring the stable and efficient operation of these equipment.

As a refractory material with excellent performance, magnesia carbon bricks play an irreplaceable and important role in industries such as steel, non-ferrous metal smelting, and glass manufacturing with their unique advantages. This article will explore the advantages of magnesia carbon bricks in depth and show their important value in the field of high temperature industry.

1. Basic composition and structure of magnesia carbon bricks

Magnesia carbon bricks are mainly composed of two key components: magnesium oxide (MgO) and carbon ©. Magnesium oxide has an extremely high melting point (2800°C) and is a high melting point alkaline oxide, which gives magnesium carbon bricks excellent high temperature resistance and good corrosion resistance to alkaline slag. The carbon element usually exists in magnesium carbon bricks in the form of graphite. Graphite has excellent electrical conductivity, thermal conductivity, low expansion coefficient and poor wettability with slag. This unique combination makes magnesium carbon bricks have both the high melting point of magnesium oxide and the many excellent properties of carbon.

From the microstructure point of view, the magnesium oxide particles in the magnesia carbon brick are evenly distributed in the carbon matrix, forming a tightly interwoven composite structure. The magnesium oxide particles are connected to each other by a carbonaceous binder. This structure not only enhances the strength of the brick body, but also provides it with good thermal shock resistance and slag erosion resistance. The carbonaceous phase plays a role of bridge and buffer in the structure, which can effectively alleviate the stress caused by temperature changes and slag erosion, and ensure the stability of magnesia carbon bricks under complex working conditions.

2. Advantages of magnesia carbon bricks

(Ⅰ )Excellent high temperature resistance

Since both magnesium oxide and graphite have extremely high melting points, and the two do not undergo eutectic melting at high temperatures, magnesium carbon bricks have excellent high temperature resistance.

In high-temperature equipment such as converters and electric furnaces for steel smelting, the internal temperature is often as high as 1600℃ or even higher. Magnesium carbon bricks can maintain stable physical and chemical properties in such extreme high temperature environments, without softening or melting, providing reliable refractory protection for the furnace body and ensuring the smooth progress of the smelting process. Compared with some traditional refractory materials, magnesium carbon bricks have more outstanding structural stability and creep resistance at high temperatures, and can withstand long-term high temperature loads without obvious deformation or damage, greatly extending the service life of equipment such as furnace linings.

(II) Strong resistance to slag erosion

Magnesia has strong corrosion resistance to alkaline slag and high iron slag, while graphite has poor wettability with slag. The combination of these two characteristics makes magnesia carbon bricks have excellent slag corrosion resistance.

In practical applications, such as in the slag line of the converter, this area is in contact with high-temperature slag for a long time and is subject to strong slag corrosion. Magnesia carbon bricks can effectively resist the erosion of slag and slow down the loss rate of bricks due to their unique composition and structure. Compared with the old fired alkaline bricks, the penetration layer of magnesia carbon bricks is much shallower, which means that it is difficult for slag to penetrate into the interior of the brick body, thereby greatly improving the anti-corrosion life of the brick body.

In addition, magnesia carbon bricks have a strong ability to resist slag penetration, which can prevent slag from penetrating and accumulating in the pores of the brick body, and avoid the destruction of the brick structure and the reduction of strength caused by slag penetration.

(III) Good thermal shock stability

Graphite’s higher thermal conductivity, lower thermal expansion coefficient and lower elastic modulus give magnesium carbon bricks good thermal shock stability.

In the industrial production process, furnaces and other equipment often experience frequent temperature changes, such as furnace opening, furnace shutdown and temperature fluctuations during production. Such rapid temperature changes will cause thermal shock to refractory materials, which can easily lead to material cracking and peeling. Due to its advantages in thermal physical properties, magnesium carbon bricks can quickly conduct heat and reduce temperature gradients when the temperature changes sharply. At the same time, its own low expansion characteristics enable it to effectively buffer thermal stress and basically avoid tissue damage and peeling caused by thermal shock. For example, in the process of electric furnace steelmaking, frequent power-on heating and power-off cooling will cause the temperature of the furnace lining to change rapidly. The good thermal shock stability of magnesium carbon bricks ensures that it can still maintain its complete structure and performance under such conditions, providing a strong guarantee for the stable operation of the electric furnace.

(IV) High high temperature strength

Magnesium carbon bricks have high strength at high temperatures and can withstand the scouring, wear and mechanical stress of high-temperature materials and airflow in the furnace.

During the steel smelting process, the molten steel, slag and high-temperature airflow in the furnace will cause strong scouring and friction on the furnace lining. The high-temperature strength of magnesium carbon bricks enables them to resist these external forces and is not prone to wear and peeling.

This high-strength characteristic not only ensures the structural integrity of the brick body in a high-temperature environment, but also reduces the number of repairs and replacements of the furnace lining caused by brick damage, improves production efficiency and reduces production costs. At the same time, the high high-temperature strength also enables magnesium carbon bricks to adapt to some special working conditions that require stringent strength of refractory materials, broadening its application range.

(V) Good anti-peeling performance

In the past, alkaline refractory materials had poor spalling resistance and were prone to spalling during use, which affected the service life of the equipment.

Magnesium carbon bricks have effectively improved this shortcoming through reasonable raw material selection and structural design. Its carbon matrix can enhance the toughness of the brick body. When subjected to thermal shock, mechanical impact, etc., it can absorb and disperse stress, prevent the generation and expansion of cracks, and thus greatly improve the spalling resistance.

In parts such as the converter cap, due to the combined effects of rapid cooling and heating temperature changes and high-temperature airflow and dust scouring, the spalling resistance of refractory materials is extremely high. Magnesium carbon bricks, with their good spalling resistance, can serve stably in this part, reducing the workload of frequent repairs and replacement of furnace linings, reducing labor intensity, and also helping to improve the quality of molten steel and production efficiency.

(VI) Low production energy consumption

As an unfired product, compared with traditional refractory materials such as fired magnesia dolomite bricks, magnesia carbon bricks save at least 80% of fuel consumption in the production process.

This is mainly because magnesia carbon bricks do not need to go through a high-temperature firing process, avoiding a large amount of energy consumption during high-temperature firing. In today’s era of advocating energy conservation and emission reduction, the low-energy production characteristics of magnesia carbon bricks have significant advantages, which not only reduces the production costs of enterprises, but also conforms to the concept of sustainable development, and has made positive contributions to the green development of the industry. Lower production energy consumption also makes magnesia carbon bricks more economically feasible in large-scale production and application, and can meet the growing market demand.

3. The advantages of magnesia carbon bricks are reflected in various industries

(Ⅰ). Steel industry

In the steel industry, the advantages of magnesia carbon bricks have been fully reflected and widely used. In the converter, the furnace mouth is constantly impacted by cold and hot molten steel, and it also has to withstand the scouring of high-temperature slag and high-temperature exhaust gas. Magnesium carbon bricks have become the ideal refractory material for the furnace mouth due to their high temperature resistance, scouring resistance, and the characteristics of not easy to hang steel and easy to clean.

Due to the combined effects of severe slag erosion, rapid cooling and heating temperature changes, and high-temperature airflow and dust, the use of magnesia carbon bricks with strong slag erosion resistance and spalling resistance can effectively extend the life of the furnace lining. The charging side requires refractory materials to have high slag erosion resistance, high temperature strength and spalling resistance. High-strength magnesia carbon bricks with metal antioxidants can meet this demand well. The slag line is the junction of the three phases of furnace lining refractory materials, high-temperature slag and furnace gas, and is most severely slag-corroded. Magnesium carbon bricks with high carbon content are widely used in this area due to their excellent slag erosion resistance.

In electric furnaces, the furnace walls are almost all built with magnesia carbon bricks, and the life of magnesia carbon bricks directly determines the service life of electric furnaces. At present, by optimizing the raw material quality of magnesia carbon bricks, improving the production process and rationally adding antioxidants, the performance of magnesia carbon bricks in electric furnaces has been further improved, the consumption of refractory materials has been reduced, and the economic benefits of electric furnace steelmaking have been improved. In the clearance and slag line of the refining ladle furnace and ladle, magnesia carbon bricks have gradually replaced the magnesia-chromium refractory materials whose use has been reduced due to chromium pollution in the past, providing reliable refractory protection for the steel refining process.

(II) Nonferrous metal smelting industry

In the process of non-ferrous metal smelting, such as the smelting of copper, aluminum and other metals, it is also necessary to carry out in a high temperature environment, and there are various complex chemical substances and high-temperature melts in the furnace.

The advantages of magnesia carbon bricks such as high temperature resistance, slag erosion resistance and thermal shock stability make them widely used in non-ferrous metal smelting furnaces. For example, in copper smelting furnaces, magnesia carbon bricks can effectively resist the erosion of high-temperature copper liquid and slag in the furnace, ensure the stability of the furnace lining, and reduce production interruptions and maintenance costs caused by damage to the furnace lining.

In aluminum electrolytic cells, magnesia carbon bricks, as lining materials, can withstand the scouring and erosion of high-temperature electrolytes and aluminum liquids. At the same time, good thermal shock stability enables them to adapt to temperature changes during the electrolysis process, extending the service life of the electrolytic cell and improving production efficiency.

(III) Glass manufacturing industry

In the glass manufacturing process, the glass kiln needs to operate for a long time at high temperature, and the performance requirements of refractory materials are extremely high.

The high temperature resistance of magnesia carbon bricks enables them to withstand high temperatures of up to 1500℃ in glass kilns. At the same time, their slag erosion resistance can effectively resist various corrosive substances in glass liquid and kiln atmosphere. The use of magnesia carbon bricks in the heat storage chamber, pool wall and other parts of the glass kiln can significantly increase the service life of the kiln, reduce the downtime caused by kiln maintenance, and improve the continuity and output of glass production. In addition, the good thermal shock stability of magnesia carbon bricks can also adapt to the temperature changes of the glass kiln during the heating and cooling process, ensuring the integrity and stability of the kiln structure.

Magnesium carbon bricks have become an indispensable key refractory material in the modern high-temperature industry due to their excellent high-temperature resistance, strong resistance to slag erosion, good thermal shock stability, high high-temperature strength, outstanding anti-stripping performance and low production energy consumption.

In the steel, non-ferrous metal smelting, glass manufacturing and other industries, the application of magnesium carbon bricks not only improves the service life and production efficiency of equipment, but also reduces production costs, making an important contribution to the sustainable development of the industry. With the continuous advancement of science and technology and the growing demand for high-performance refractory materials in industrial production, it is believed that magnesium carbon bricks will show more excellent performance and broader application prospects through further technological innovation and performance optimization in the future, and continue to promote the development and progress of the high-temperature industry.

Classification, application, ratio of raw materials and damage mechanism of blast furnace mud

Clay is an amorphous functional refractory material, used in the process of plugging the taphole of the ironmaking blast furnace. The composition of gun mud can be divided into two parts: refractory aggregate and binder. Refractory aggregate refers to refractory raw materials such as corundum, mullite, coke gemstone and modified materials such as coke and mica, which are used to improve the refractoriness, high temperature performance and slag resistance of gun mud; the binder is water, tar pitch or phenolic Organic materials such as resin can also be mixed with SiC, Si₃N₄, expansion agents and additives to improve the physical properties and product quality of the gun mud.

According to the different binders, gun mud can be divided into two categories: water gun mud and waterless gun mud. Domestically, medium and small blast furnaces (<2000m³) with low top pressure and low level of intensified smelting use water blasting mud; while large and medium blast furnaces (>2000m³) with high top pressure and high level of intensive smelting are generally used Anhydrous cannon mud. Many foreign blast furnaces represented by Japanese blast furnaces generally use high-quality anhydrous gun mud, and are equipped with special opening methods and opening machines.

The water cannon mud is usually made of clay, coke powder, bauxite clinker and tar pitch as the main materials, and then mixed and stirred with water as a binder. Water cannon mud is a kind of cannon mud that was used in large quantities in the early days, but because of its relatively small bulk density, its ability to resist scouring of iron slag solution is weak, it is easy to cause insufficient hole depth when used on large and medium blast furnaces and runaway during tapping. Phenomena such as coke, iron tapping and venting and unclean iron slag will affect the normal production of the blast furnace. So far, due to the low cost of water gun mud, many medium and small blast furnaces (<2000m³) are still improving their composition and working hard to adapt to the smelting environment, and their unit consumption is above 1.2kg·t⁻¹.

Anhydrous gun mud generally uses corundum, high alumina bauxite, clay, sericite, pitch, silicon carbide, coke powder, etc. as raw materials, and tar, resin, etc. as binders. The bulk density of corundum and high alumina bauxite is relatively large, and they play the role of supporting the skeleton in the gun mud, which is the foundation of the gun mud strength, which greatly improves the ability of the gun mud to resist the scouring of the iron slag solution; the coke powder has good reduction It can protect other carbon components, maintain the reducing atmosphere of the blast furnace taphole, and has good thermal conductivity, which can be quickly sintered and has a certain sintering strength; silicon carbide has small thermal expansion coefficient, good thermal conductivity, and excellent thermal shock resistance, which can improve The refractoriness, volume stability, high temperature strength and erosion resistance of gun mud; clay and asphalt improve the plasticity of gun mud; sericite improves the sintering strength and plasticity of gun mud. Anhydrous gun mud has the advantages of no dampness, high strength, stable taphole depth, small taphole changes in the tapping process, etc., and will not cause a large flow.

The main factors affecting the performance and quality of blast furnace clay are raw materials, binders, additives and production processes.

Blast furnace taphole clay must have the following properties:

(1) Easy to open holes. When the tap hole needs to be tapped, the sintered gun mud in the tap hole can be easily drilled through the hole and tapped in time;

(2) It is easy to block the tap hole. When the tap hole is completed, the tap hole can be blocked in a short time, and sufficient mud volume is ensured to maintain a stable tap depth;

(3) Good adhesion. The new gun mud driven into the tap hole must have good adhesion with the old gun mud in the hole to make the new and old gun mud form a whole to prevent the existence of gaps. Iron seepage, slag seepage, impact on tapping and safety accidents in front of the furnace;

(4) Good sinterability. The shot mud can be sintered to different degrees in the three temperature stages of low temperature, medium temperature and high temperature. The iron hole is blocked in time and a large enough mud bag is formed in the hearth. Play the role of protecting the hearth lining bricks.

(5) It has good jet scouring and corrosion resistance, so that the tap hole diameter is not sharply enlarged, and the tapping time is guaranteed to be 150 to 180 minutes/time, which reduces the labor intensity in front of the furnace and reduces the consumption of materials in front of the furnace.

The main damage mechanism of blast furnace mud

Thermal stress damage. When the iron is tapped, the center of the iron hole is drilled by a drill bit, and hot molten iron and molten slag flow out of the iron hole, so that the iron hole can withstand high temperature above 1500 ℃. When the iron slag is discharged and the iron hole is re-blocked with gun mud, the old gun mud contacts the newly plugged gun mud, and the temperature drops rapidly from 1500°C to about 200°C. This repeated action generates huge heat inside the old gun mud. Stress can easily lead to arc-shaped cracks with the iron hole as the center.

Thermal chemical attack. Prolonged contact with molten iron and molten slag can cause chemical reactions to cause erosion of the mud. The reaction generates a low-melting mineral phase, which is lost with the scouring of the molten iron slag during the tapping period, which enlarges the hole diameter of the tap hole, causing the molten iron to rush out of the tap hole quickly, affecting the stability of the tap hole.

The biggest weakness of the current blast furnace mud is that the iron mouth expands quickly and the resistance to hot metal erosion is insufficient, which causes the molten iron in the hearth of the blast furnace to be unclean, affects the output, and is not conducive to the smooth movement of the blast furnace. In addition, it is difficult to open the iron hole, which causes the iron hole to be unable to open on time and affects the normal iron casting. Therefore, many large-scale blast furnaces at home and abroad use the plunger method or are equipped with opening machines with strong positive and reverse impact capabilities to solve the problem of difficult opening of blast furnace mud. Under normal circumstances, after the blast furnace is finished, the surface of the original gun mud seeps into the iron slag. After the new gun mud is plugged into the iron hole, a barrier is formed at the junction of the old and the new gun mud, which is not conducive to bonding. As a result, the molten iron in the blast furnace will enter along the gap between the new and old gun mud, resulting in a slag-iron penetration area in the middle of the gun mud. The formation of the slag-iron penetration area also increases the difficulty of the taphole opening to a certain extent. The iron gate is not easy to open, which can easily lead to major safety production accidents. At home and abroad, great attention is paid to the on-site operability of blast furnace taphole mud.

It is not only the quality of the refractory lining that affects the life of the converter

There are many factors that affect the damage of converter bricks, which are related to factors such as matte grade, refractory material quality, masonry technology, blowing system and actual operation.

 

1. Masonry and lining damage of converter

There are 2 60t converters in our factory. The masonry structure of the converter is: blasthole bricks 520mm, above the blasthole, there are 9 layers of 520mm and 14 layers of 460mm transition zone, below the blasthole zone is 380mn, and the furnace mouth is built with refractory Material, masonry is thicker in the wind eye area and above, in order to enhance the corrosion resistance.

Production practice shows that the vulnerable parts of the converter lining are: furnace mouth, wind eye, end wall. During the blowing process, it is subject to severe mechanical erosion of high-temperature melt, severe erosion of slag and quartz flux, periodic fluctuations of furnace temperature, mechanical collision and abrasion during furnace mouth cleaning and wind eye maintenance, and the operating conditions are extremely harsh, especially for furnaces. The three parts of the mouth, wind eye, and end wall slag line are not only the vulnerable parts of refractory materials, but also the weakest link of the masonry structure, and the parts that require the highest technical content in road construction. The synchronous life of these three parts largely represents the age of the converter.

According to production practice, when the thickness of the bricks in the blast hole area of ​​the converter is less than 90mm, they can no longer be used, and the furnace needs to be stopped for digging. When the remaining parts of the masonry are below 150mm, the furnace needs to be shut down for overhaul.

 

2. Analysis of factors affecting converter life

There are many reasons for the damage of the converter lining. In summary, they are mainly the result of mechanical force, thermal stress and chemical corrosion.

2.1 The influence of mechanical force

2. 1.1 Damage to brick lining caused by the energy of stirring the melt

Due to the impact force of the blown gas and the rise and expansion of the air flow, a large amount of stirring energy is brought to the melt. When the gas-liquid two-phase mixed fluid impacts the surface of the melt, the melt is sprayed onto the brick lining by the gas-liquid two-phase fluid It causes strong mechanical impact on the furnace lining and creates conditions for chemical erosion. Therefore, choosing a reasonable blast intensity is an important part of improving the life of the converter. A relatively suitable air supply intensity and air supply system will help weaken the melt’s impact on the furnace lining. The impact force extends the life of the converter.

2. 1. 2 Clean up the damage of the wind eye to the wind eye brick

In the blowing process, magnetic iron is inevitably generated. When the wind eye is operated, the melt in the tuyere area is recharged, and nodules are easily formed at the tuyere. The tuyere needs to be cleaned continuously, and the damage effect of mechanical vibration on the brick lining in the tuyere area It is very large, causing the surface of the brick lining in the tuyere area to deteriorate under the action of melt erosion. When the metamorphic layer expands to a certain extent, the brick body will peel off, which seriously affects the furnace life.

2.2 The influence of thermal stress

The resistance of refractory materials to damage caused by temperature changes during heating and cooling is called thermal shock resistance, which is an important indicator of the quality of refractory materials. Most refractory materials are damaged due to poor thermal shock resistance at temperatures much lower than their refractoriness. The thermal damage of refractory materials is mainly related to the thermal stress produced by refractory materials during the production process.

The converter is a periodic operation, and it is inevitable that the temperature of the converter will fluctuate due to the failure of the material, the repair of the furnace port and the failure of the equipment during the production.

2.3 Effects of chemical attack

Chemical attack mainly has two forms: melt erosion (slag, metal solution) and gas erosion. It is manifested in the dissolution, combination and penetration of magnesia refractory materials, which changes the structure of refractory materials and weakens their performance.

2. 3. 1 Melt erosion

The melt contacts and penetrates through the pores, cracks and the interface between the refractory materials. During the contact process, the refractory material dissolves into the melt, and the surface of the refractory material forms an easily soluble compound whose bulk density changes greatly with the raw material. When it dissolves to a certain extent, the infiltration occurs. When the melt penetrates the refractory material to a certain depth, it will produce The metamorphic layer with completely different properties of the raw material changes in volume due to the different structure of the metamorphic layer and the raw material, resulting in structural stress, which leads to cracks in the production of raw materials. Serious cracks cause the metamorphic layer to peel off or crack, and new materials will be generated under the erosion of the melt. Refractory material is seriously damaged by this cycle.

2. 3. 2 Gas erosion

Gas erosion generally refers to the reaction of the so 2 and o 2 in the copper matte with the alkali oxides in the refractory during the blowing process to form metal sulfates, and its density is lower than that of the alkali oxides. The difference in phase bulk density produces stress, which makes the refractory material loose and peels off, and aggravates the damage of the refractory material.

 

3. Measures to extend converter life

3. 1. Change the masonry method and improve the process standard:

3.1.1 Under normal circumstances, wet masonry will cause the brick body to become damp, which is not conducive to constant temperature dehydration at 400 ℃. The masonry of the converter adopts a combination of dry and wet, that is, the upper and lower 4 layers of the tuyere area and the furnace mouth area are made of wet masonry, and the rest are dry-laid.

3.1.2 The masonry of the tuyere bricks was changed from one end to the middle to both ends to avoid triangle joints and dislocation of the tuyere combination bricks.

3.1.3 Changed from laying on one end and lower furnace mouth reverse arch bricks to masonry from the center to both ends, and proceeded symmetrically, which is conducive to closing and locking on both sides, and preventing the uneven and tight gap between the two bricks from falling off .

3.1.4 The distribution of the brick joints is substantial, uniform, and the inside and outside are consistent. The expansion joints meet the requirements of 2-3 mm. The joints of each part of the brick body shall be locked, and the processed brick body shall not exceed one-third. The processed brick Body is not less than two-thirds of itself.

3.1.5 Magnesium fillers are required to be kneaded into a mass by an expert hand, and scattered from a height of one meter. The thickness of the filler is uniform and the firmness is uniform.

3.1.6 Damaged, broken corners and damp chrome-magnesium bricks must not be used.

3.2. Control the converter cold material to prevent high temperature corrosion

The test proves that when the chrome-magnesia brick has thermal vibration resistance at 850 ℃, it will break and break 18 times, resulting in damage to the brick lining. Therefore, it is necessary to prevent the furnace temperature from rising and falling and violent fluctuations, and to reduce and eliminate the damage to the brick lining caused by thermal stress. In production, the method of controlling the amount of cold material added is used to stabilize the furnace temperature.

3.3. Reasonably control the silicon content of converter slag, reduce chemical corrosion, neutral or weak alkaline slag, and protect the brick lining. Ferroolivine corrodes severely, and it can not only dissolve the surface of the magnesia refractory, but also penetrate into the interior to dissolve. The higher the temperature, the greater the solubility of M g O in converter slag, and the formation of forsterite with a lower softening temperature under load at high temperatures, which reduces the working performance of the magnesia brick. Iron oxides can also saturate periclase and chromite crystal grains, cause crystal grain damage, and cause magnesia bricks to be damaged too quickly. The converter slag contains less than 18% silicon and is alkaline, while the converter slag contains more than 28% silicon and is acidic. Both of them seriously corrode the lining of magnesia bricks. The converter slag contains between 19% and 24% silicon, which is neutral or weakly alkaline and does not corrode the lining of the magnesia brick. In production, the silicon content of converter slag is strictly controlled to stabilize it between 19% and 24%.

3.4. Improve personnel quality

Improve the quality and ability of furnace building, converter operations, and production managers to ensure the quality of furnace building. Improve the ability to respond to emergencies, scientifically and strictly supervise and manage production.

3.5. Reasonable selection of air supply intensity and oxygen enrichment concentration

It is inevitable that the furnace body and the fan do not match during the production process. It is strictly forbidden to use a large fan to supply air to the small furnace body to prevent the tuyere area from being washed out and the melt is severely sprayed. The oxygen-enriched concentration of the converter should not be higher than 27%, and the oxygen-enriched concentration should be greater than 27%, which will wash the brick lining more.

 

4. Issues that should be paid attention to

The following aspects should also be paid attention to in production:

(1) Formulate scientific standards for shutdown, repair and start-up, such as brick lining removal standards, heating standards, etc., and strictly implement them. (2) When the newly repaired furnace body is started, the operations of "hanging the furnace" and "copperizing" should be carried out to protect the furnace body.

(3) Strict process operation, the control of the furnace temperature at each stage and the judgment of the end point must be accurate. Prevent the occurrence of "overblowing", especially the second-cycle overblowing, which will cause serious damage to the furnace body.

(4) Attach importance to the training of employees and improve the quality of all employees and the level of copper smelting technology.

 

5. Summary

Through the implementation of the above measures, the energy consumption per ton of copper bricks is well controlled, costs are reduced, and annual benefits are created. As long as attention is paid to masonry quality, process conditions, and elimination of the thermal stress, mechanical force and chemical corrosion factors that damage the chrome-magnesium bricks, the life of the furnace bricks can be prolonged.

The Turkish steel industry, which has 24 electric arc steel plants, has made another big move! Erdemir acquires Kümaş

Focus on:

·Kümaş, a leading company in magnesium and refractory materials, was acquired

·Kümaş joins Almatis and belongs to OYAK Group

·As end users have requirements for supply security, the vertical integration strategy begins

·The purchase price of 340 million US dollars

Turkey’s Kümaş Manyezit Sanayi A.Ş. (Kümaş), one of the world’s major magnesia producers, was acquired by Turkish steel leader Ereğli Demir ve Çelik Fabrikaları T.A.Ş. (Erdemir) for US$340 million.

The equity conversion agreement was officially signed on January 4, 2021. The current share ratio is

Erdemir’s owner Gözde Girişim Sermayesi Yatırım Ortaklığı A.Ş. holds 51% and Kümaş’s owner Yıldız Holding A.Ş. holds 49%. The agreement will come into effect after the law is approved.

Erdemir is a member of the metallurgical mining group OYAK, which is also Turkey's largest supplementary occupational pension fund with total assets of approximately US$16 billion and is headquartered in Ankara.

The OYAK Group has a wide-ranging industrial and service portfolio, including its chemical products group (the group acquired Almatis, the world's leading specialty alumina producer in 2015). Almatis and Kümaş are both major material suppliers for the global refractory market.

This advancement also optimizes the group’s market share, strengthens the general ownership trend, and reduces competition among magnesia producers, because they are grouped into a larger group of magnesia refractories and directly face end users group. A similar incident occurred a year ago when Sibelco sold QMAG, a leading manufacturer of magnesium oxide, to Refreshnik, a major German refractory manufacturer.

At present, magnesia suppliers other than China are mainly distributed in Mexico, Brazil, the Netherlands, Ireland, Spain, Greece, Turkey, Austria, Slovakia, Russia, Japan and Australia. The resources emerging in recent years mainly come from Greece, Turkey, Saudi Arabia, Jordan, Serbia and Turkey.

In a statement issued on January 5, 2021, OYAK stated that the acquisition is mainly aimed at achieving cost control and efficiency by ensuring the vertical integration of its activities in the steel and cement industries. It is also to protect the value of national resources. There is no doubt that the synergy after integration will increase.

On August 11, 2020, OYAK Group also integrated and acquired 60% of the shares of Haznedar Durer refractories from Imerys, a global industrial mineral producer that was headquartered in Paris.

As we all know, RHI Magnesita (RHIM), a global manufacturer of magnesium and refractories based in Vienna, has established a magnesium oxide plant (MAS, Eskişehir) in Turkey. In the past two and a half years, Kümaş has been closely monitored, and he participated in the acquisition in May last year, but it was not successful.

Kümaş’s main mineral products include heavy burnt magnesia (annual production of 300,000 tons); fused magnesia (annual production of 40,000Tons); light burned magnesia (annual production of 100,000 tons) and heavy burned dolomite (annual production of 20,000 tons). Refractory materials

It mainly produces refractory bricks and mortar based on magnesium, dolomite and alumina, with an annual output of approximately 150,000 tons. OYAK mainly produces steel products, which require the use of magnesia refractory materials and chemicals.

The steel industry in Turkey is in good condition, including 24 electric arc furnace plants, 7 induction furnace plants and three alkaline gas plants. In 2020, when the epidemic is pandemic, Turkey is also bucking the trend, and steel production is expected to exceed 2019.

Turkey is currently the second largest steel producer in Europe and is expected to surpass Germany in the future. OYAK continues to invest overseas, with the goal of becoming the world's top 5 in the next five years. For the circular economy, the group also has specific plans.

OYAK not only owns the steel and refractory business, but also covers the fields of agriculture, chemistry, cement and paper making.

According to our survey, Kümaş is the largest producer of magnesite products in Turkey. It has a wealth of magnesite and dolomite deposits in Turkey, and is the second largest producer of magnesite after China. In terms of magnesia production, it is second only to China and Russia, ranking third in the world and fourth in export volume.

Figure 1: 2019 global magnesite reserves and production

Figure 2: 2019 global magnesia supply and transactions

It is understood that Kümaş has 163 million tons of magnesite resources, of which high-quality cryptocrystalline magnesite reserves account for about 20% of the world. It is characterized by very fine magnesite crystals, usually 1-10μm, with high surface area and High reactivity. In addition, there are about 96 million tons of dolomite resources.

The other two major magnesite producers in Turkey are Magnesit AŞ and Eskişehir under RHIM, with an annual capacity of 260,000 tons of heavy burned magnesia, and Konya Selçuklu Krom Magnezit Tuğla Sanayii AŞ, Konya, with an annual capacity of 45,000 tons of heavy burned magnesia. .