Month: September 2023

Configuration of Magnesia-Chrome Bricks for Copper Smelting Thermal Kilns

KilnRefractory

Magnesia-chrome bricks are the most commonly used refractory bricks in copper smelting thermal kilns. Configuration of magnesia-chromium bricks for copper smelting thermal kilns. In common copper smelting thermal kilns such as top-blown converters, horizontal converters, anode furnaces, flash furnaces, electric furnaces, Kifset furnaces, Ausmet furnaces, reverberatory furnaces, oxygen-rich bottom-blown furnaces, etc. Magnesia chrome bricks are the main configuration.

RS Magnesia Chrome Brick
RS Magnesia Chrome Brick

As the name suggests, magnesia-chrome bricks are made of sintered magnesia and chromium sand according to certain proportion requirements and are shaped and sintered by adding additives. According to their chemical properties, magnesia-chromium bricks are alkaline refractory bricks. It is most widely used in non-ferrous metals, especially copper smelting. Secondly, it is also widely used in cement production.

Magnesia chrome bricks can be roughly divided into six different types according to their production methods. 1) Silicate bonded magnesia chromium brick. 2) Directly combine magnesia chrome bricks. 3) Electrofusion rebonded magnesia chromium brick. 4) Semi-rebonded magnesia-chrome bricks. 5) Fused magnesia chrome bricks. 6) Chemically bonded unburned magnesia chromium bricks. Among them, among the thermal kilns for copper smelting, the most widely used ones are directly bonded magnesia chromium bricks, semi-rebonded magnesia chromium bricks and electrofused rebonded magnesia chromium bricks.

Application of Magnesia Chrome Bricks in Flash Furnace Reaction Tower
Application of Magnesia Chrome Bricks in Flash Furnace Reaction Tower

Directly bonded magnesia chrome bricks

Directly bonded magnesia-chromium bricks have high-temperature strength, slag resistance, erosion resistance, erosion resistance, corrosion resistance, excellent thermal shock stability and volume stability at 1800°C. Directly combined with the main application parts of magnesia-chromium bricks, the bottom of the top-blown converter, the non-working layer of the furnace wall, and around the horizontal converter barrel. Around the cylinder of the anode furnace, there are the walls of the Kifset furnace, the walls of the Ausmet furnace, the top and walls of the reverberatory furnace, and the upper part of the oxygen-rich bottom-blown slag line.

Electrofusion rebonded magnesia chromium brick

Electric fused rebonded magnesia chromium bricks are made by melting the raw materials using the electric fusion method to make fused magnesia chromium materials, crushing them into a certain particle size, and then mixing, shaping, and sintering them. Combined with the magnesia-chromium brick, it is a fine-grained matrix with evenly distributed pores and micro cracks, and is more sensitive to sudden temperature changes than melting and casting. The high-temperature performance of electrofusion rebonded magnesia chromium bricks is between that of fused cast bricks and directly bonded bricks. The main application part of electrofusion rebonded magnesia-chromium bricks is the working layer of the top-blown converter furnace, which is in direct contact with the copper liquid. Horizontal converter furnace mouth. The mouth of the anode furnace. Flash furnace reaction tower. Electric stove mouth. Kifset furnace bottom working layer. Ausmet furnace furnace wall and furnace bottom. The lower part of the oxygen-rich bottom-blown slag line and the wind eye area.

Semi-rebonded magnesia chrome bricks

Semi-rebonded magnesia-chromium brick refers to a kiln refractory product fired from part of the fused magnesia-chromium sand as raw material. The main mineral composition of semi-rebonded magnesia-chromium bricks is periclase, spinel, and a small amount of silicate. Its thermal shock resistance is better than that of directly bonded magnesia-chromium bricks. The main application parts of semi-rebonded magnesia-chromium bricks are the walls of flash furnace sedimentation tanks. Electric furnace hearth. Ausmet stove. The working layer is at the bottom of the reverberatory furnace and the copper outlet.

In actual applications, reasonable magnesia-chromium brick configuration should be carried out according to the kiln structure and working environment. In addition to the above-mentioned magnesia-chromium bricks, magnesia-chromium unshaped refractory materials such as magnesia-chromium ramming materials, magnesia fillers, and magnesia-chromium castables are also used in copper metallurgical thermal kilns.

Magnesia Chrome Bricks for Flash Furnace Melting Pool
Magnesia Chrome Bricks for Flash Furnace Melting Pool

Application advantages of magnesia chrome bricks in copper smelting furnaces

In the development history of magnesia-chromium refractory materials used in the copper smelting industry, silica bricks were first used to build furnace linings. However, since the slag composition contains FeO and SiO2, and the smelting atmosphere contains a lot of SO2 acidic gas, the erosion damage of the silica bricks is very serious. From the 1950s to the 1960s, alkaline bricks have been used in the copper smelting industry. Today, after several generations of continuous improvement, the production process of magnesia-chromium refractory materials and its application in the copper smelting industry is becoming more and more mature.

Currently, direct-bonded magnesia-chromium bricks are widely used in converters. The technology of directly bonding magnesia-chromium bricks to build the furnace body, and using electric fusion and then bonding magnesia-chromium bricks to build the tuyere, furnace mouth, and other positions to build the converter lining has been applied.

Taking the lining construction of a 150t copper converter in a certain factory as an example, ordinary silicate-bonded magnesia-chromium bricks are used to build the cylinder and end wall linings. Directly bonded magnesia-chromium bricks with high chromium content have been used in locations such as tuyere slag lines that are severely corroded, and good results have been achieved.

A copper factory also achieved good results by using improved electric fusion combined with magnesia-chromium bricks to build tuyere, extending the furnace life and reducing the period of minor repairs.

Generally speaking, ordinary magnesia-chromium bricks are currently used to build furnace linings. The general method of constructing the copper converter lining is to use directly bonded bricks or electro-fused rebonded magnesia-chromium bricks to build the tuyere, slag line, furnace mouth, and other locations.

What are the Advantages of Applying Ceramic Fiberboard to Industrial Furnaces?

KilnRefractory

The main raw material of ceramic fiberboard is aluminum silicate, which is one of the important guarantee factors for the kiln to save energy, reduce consumption, and optimize high production. According to the temperature division, fiberboard can be widely used in the backing of industrial kilns or the hot surface of low-temperature kilns. If you want to ask, what advantages does ceramic fiberboard have in industrial furnaces? Then its advantages are still obvious.

Ceramic Fiber Insulation Board
Ceramic Fiber Insulation Board
  1. The specific heat capacity (storage heat) is small. One of the reasons why ceramic fiberboard can reduce the maintenance cost of industrial kilns is its small specific heat capacity, which can save energy during the shutdown and start-up of the heating furnace.
  2. Low thermal conductivity. The ceramic fiberboard furnace lining has low thermal conductivity and a good heat insulation effect.
  3. Good thermal shock resistance. The porosity of the ceramic fiber board is high, and the ceramic fiber lining can meet various rates of heating or cooling without damage (under the premise that the kiln body can bear it).
  4. Good sound insulation performance. Ceramic fiber board has good sound insulation ability, can reduce noise pollution, can be used as sound insulation material, and can also be used as wall insulation and sound insulation material in buildings (such as structural insulation integrated ceramic wool composite insulation board).
  5. Stable chemical properties. The main chemical composition of ceramic fiberboard is aluminum silicate, which does not easy to be corroded except for the reaction with strong acids and alkalis.
  6. Wide application range. Refractory ceramic fiberboard can meet the requirements of different operating temperature ranges (such as between 600°C and 1300°C). Different industrial furnaces that can be applied to different industries require the use of refractory ceramic fiber boards.

What is the Insulation Effect of Ceramic Fiberboard?

What kind of insulation effect does the ceramic fiber board play? Ceramic fiber board is also called ceramic cotton board, which has good characteristics of high-temperature resistance, heat preservation, and heat insulation, and is widely used. Ceramic fiber boards can be used for the lining of highly heat-sensitive furnaces. So what is the so-called high heat-sensitive stove?

The so-called high heat sensitive furnace means that the furnace can effectively control the heating or cooling speed. In contrast, what is thermal inertia? This means that when the furnace is heated, the heat is almost absorbed by the furnace lining, the furnace temperature is almost synchronized with the furnace wall temperature, and the heat rises slowly. When cooling, almost all the heat is from the furnace wall, and the furnace temperature drops slowly. If the cooling or heating time is too long, it will waste a lot of fuel, and reduce production efficiency and product quality.

The lining material determines how to increase the heat sensitivity of the furnace.

Different from the traditional refractory brick lining, ceramic fiber boards can effectively improve this problem. The ceramic fiber material has a low thermal conductivity and hardly absorbs the heat of the furnace, effectively reducing heat loss and shortening the heating time. When the temperature is lowered, the heat storage capacity of the furnace is reduced, and the heat sensitivity of the furnace is increased.

RS High-Quality Ceramic Fiber Insulation Board
RS High-Quality Ceramic Fiber Insulation Board

Application of Ceramic Fiber Products in the Steel Industry

The refractory lining of traditional industrial kilns has a large weight, the waste of heat storage in the furnace body is serious, and the heat preservation effect is poor. The temperature of the cold surface of the furnace body exceeds 100°C, and it is difficult to precisely control the temperature of the furnace. In recent years, the ceramic fiber module refractory lining of the furnace wall and roof of the industrial furnace has been designed with a full fiber lining. Due to the low thermal conductivity, low density, and light weight of fibers, lighter steel frame support structures are used in the design and construction of kilns. As a result, the development of industrial furnaces has entered the era of “kiln lightweight”. The heat storage of fibers is small, which is suitable for the operation mode of rapid heating and cooling. In addition, the ceramic fiber module can be processed into special-shaped products to adapt to various shapes of the inner wall of the furnace shell. The fiber module has good resistance to mechanical vibration and shock and has good chemical stability. These advantages have played an important role in promoting the development of new kilns.

Taking heating furnaces in the steel industry as an example, ceramic fiber modules are mainly used for ladle covers, billet carriers, furnace walls of heat treatment furnaces, etc. At present, a large number of ceramic fiber modules are used as linings in heat treatment furnaces that require high furnace cleanliness. In the annealing furnace for cold-rolled strip steel, from the heating section to the cooling section, from the top to the bottom of the furnace, ceramic fiber modules are used as linings. In the direct fire heating part of the preheating section, the hollow module is convenient for direct installation of the burner. On the furnace wall of the heating section, in order to cooperate with the installation of the radiant tube, the entire furnace wall module adopts the form of B, and at the journal of the furnace roller, the module can be made into a bell shape. Very convenient for furnace lining installation. In order to prevent fiber shedding from polluting the steel strip, aluminum cloth can also be sewn on the module as an inner lining. Special-shaped modules can be used in some special-shaped parts such as the furnace throat and the bottom chamber.

The good thermal insulation performance of the ceramic fiber module makes it widely used in the thermal insulation layer of high-temperature industrial furnaces. RS Kiln Refractory Material Manufacturer is a powerful refractory material manufacturer. Our refractory products have been sold to more than 100 countries and regions all over the world. Moreover, our technical team is committed to the R&D, design, and construction of refractory materials for the insulation layer. Our new thermal insulation material products can achieve a body density of less than 0.4g/cm3. Contact us for free samples and quotes.