The erosion mechanism of refractory brick

Both the wet process kiln, or new dry rotary kiln, in the clinker calcinations process, because the kiln gas temperature is much higher than the temperature of the materials, kiln rotates one circle, kiln lining surface is subjected to thermal shock cycle, changes in temperature range of 150 ~ 250 DEG C, 10 to 20mm in the kiln lining surface within the scope of generating heat stress. Kiln lining also bear due to the rotation of the brick kiln alternating radial and axial mechanical stress, and calcining materials erosion wear. Due to simultaneous silicate melt, easily in the environment of high temperature and kiln refractory lining surface interaction between the formation of the initial layer, and at the same time along the internal refractory brick pores to refractory bricks, refractory bricks with bonded together, make the refractory brick surface 10 ~ 20mm within the scope of the chemical composition and phase composition changes, techniques to reduce the performance of refractory brick. When the sintering range of material forming narrow or short flame burning urgency to produce local high temperature, the lowest temperature of kiln will make the skin surface is higher than that of material liquid solidification temperature, kiln skin surface layer from solid to liquid and fall off, and from the outside to the inside into the initial kiln crust is formed after the initial layer of the new kiln crust. When this happens repeatedly, firing zone kiln gradually thinned, even completely off, leading to local exposed kiln body and red kiln. In fact, firing zone kiln lining damage is that, in the high temperature region residual firebrick thickness is substantially larger radius of curvature of the curve distribution of arc bottom, sometimes falls on the inner surface of the kiln.

Relationship between refractory brick wear resistance and temperature

What is the relationship between the wear resistance of  refractory bricks and temperature, so here simply said what is the relationship between the wear resistance of a refractory brick and temperature.

Some materials such as silicon aluminum refractory brick, it is generally believed that under certain temperature (such as 700 ~ 900 DEG C within the elastic range), the higher thetemperature wear resistance is lower, can think that when temperature increase with the increase of elastic modulus decreased, wear resistance. When the temperature rises, reaching a maximum of elastic modulus, with lower elastic modulus, wear resistance increase instead. Such as aluminum silicaterefractory brick in 1200 ~ 1350 DEG C, wear resistance even better than normal temperature, when the temperature is further increased, up to 1400 DEG C + for refractory brick in liquid phase viscosity decreases sharply decreased, wear resistance. Some brick such as chrome quality products, with the temperature increasing, the wear resistance increased.

Above is the small make up to introduce the content of refractory brick, for more information, welcome to inquire or click the view http://www.chinafirebrick.com/Fire-Brick11.html. For the product, Changxing refractory material factory, welcome to visit: http://www.chinafirebrick.com

Using requirements of boiler with refractory material

Boiler burner band main properties of refractory material should have included slag resistance, high strength, wear resistance, thermal stability, thermal conductivity and other properties. The traditional refractory belt mainly used chrome refractory ramming material, but because of the domestic high quality chrome resource scarcity, therefore is the main use of silicon carbide ramming material, silicon carbide high alumina coating material, high aluminum phosphate can be plastic, high temperature expansion plastic.

Of which the first two kinds of materials of high prices, but the long service life, good performance, and then two kinds of material price is low, but performance in general, and short service life. Therefore in the cyclone furnace liquid slag furnace and should not be used in high phosphate refractoryplastic or ramming material,to avoid peeling or cracks in use in the production, so as to enhance the slag resistance of material and reduce the repair frequency.

High-temperature micro expansion refractory plastic and super 3000 water clayrefractory material performance fairly, has shown some advantages in the application to the wall pipe and boiler furnace top. But this kind of material in its solidification time is long, easy to dry shrinkage crack, thus for the construction and maintenance of a great deal of trouble. At the same time the supplier quality there is a certain fluctuation, sometimes refractoriness and normal temperature strength of less than 1580 degrees and 981N/cm2.

Selection of additives in firebrick

Resin bonded carbon magnetite brick because of its good thermal shock resistance and slag resistance of iron and steel industry, in particular applied basic oxygen furnace and electric arc furnace. Carbon has excellent performance such as high thermal conductivity, low thermal expansion coefficient, high heat shock stability, at the same time and wettability of the job of slag has good corrosion resistance and anti erosion ability. As is known to all, the brick body carbon easy oxidation, which restrict its use in high temperature, the oxidation of carbon from the beginning of the 300 DEG C, with the increase of temperature oxidation speed.

Ceramic materials (SiC, carbon silicon oxide) do coating in the flake graphite or carbon fiber, were impregnated with phosphate, cement foam board price and the use of surface glaze etc… These expensive methods used in the refractory brick have certain limitations, another method is through the steam treatment of fine particle boron, TiB2, ZrB2 and SiC and other materials to do thermal barrier coating on graphite or carbon composite material.

A common method of refractory brick is to add fine-grained antioxidant materials, such as in MgO C SiC, B4C, brick added metal Al, Mg and (or) Si to prevent or limit carbon at high temperatures (> 1400 C) oxidation. Also, these additives are expensive, and can not completely prevent the oxidation of carbon at low temperature. Coating solution by liquid mixing 60% solid and 40% made, wherein the liquid binder is phosphoric acid and ethanol (liquid solution 30%) mixture. The outer coating brush MgO C brick thickness is about 0.8mm, the sample coating drying at room temperature is about 10min. In practice, the ladle after 5h pre heated to 1200 DEG C, because of some difficulties in the process of steel-making and sometimes need a longer time.

Check method of refractory castable strength

The particle size of castable refractory refers to the particle size, usually expressed in diameter, size, size and shape of the refractory castable composition of great influence on the quality of masonry, today Changxing engineer for everyone to explain granularity inspection method of refractory castable.

The size and composition of the first use of check size sieving method, screening method requires specialized laboratory, is carried out in the laboratory, it can measure the percent composition of various size.

Then check the size shape, size of general shape according to the usual experience, for the eye visual. Check the size strength can be used sticks to beat the breaking even, observation.

Overall, granularity inspection of refractory castable must installation drawings technical requirements to determine, the particle size should not exceed the maximum size, so as not to affect the use. Xinmi Changxing Refractories Co, Ltd. (www.yilongrefractory.com) specializing in the production of various kinds of castable, welcome to buy.

The influence factors of refractory material mixing homogeneous degree

(1) the powder particle shape of powder particle shape is different, the time and the effect of mixing are not the same, such as approximate spherical particles in the friction force issmall, the speed of relative movement in the process of mixing, so easy to mix evenly; and angular particles within the large friction force, is not easy to mix evenly, compared with the former, mixing time is relatively longer.

(2) The influence of the structural characteristics of mixing equipment for material mixing quality by using wet mixing mill mud, uniform and dense, good plasticity, and using biaxial mixer mixing mud quality is poor.

(3) Mixed with the length of time the general situation, the mixing time is long, the more uniform mixture. Mixing stage, uniformity increases very quickly, when mixing to a certain time, another long time effect on the uniformity of is not obvious. General to join the species more or poor dispersion of mud, mixing time should be longer. For example, clay brickrefractories used in wet grinding machine mixing, time is 4-10min; silica brick material about 15min; magnesia brick material needs 20 – 25min.

The mixing time should not be too long, otherwise there will be the following: 1) the size composition is then broken and change; 2) mud fever and the influence of moisture content, or because the mud is too hot, and the moldings will elastic aftereffect increases when pressurized and spallation occur.

(4) The adding sequence of feeding sequence has great influence on the mixing, if the coarse – fine powder is added at the same time, the fine powder into small particle concentration and the emergence of “white material easy to appear”.

Generally used for feeding sequence:

1) Course feed – water and waste paper pulp – fine powder.

2) Part of pellet feed – water and waste paper pulp – powder – residual particles.

In addition, the reasonable selection of binder and properly controlling the amount and uniformity of mixing the clay.

Improve the heating and heat transfer capability of the refractory brick

Welding of zinc pot can be used when the E-422 electrode (to ensure the chemical composition). Zinc pot four angle should be circular arc, increase the zinc liquid liquidity to avoid local overheating four angles. According to practical experience, zinc pot such a production cycle service life up to 56 months by using electric heating, fuel (gas) heating can reach 45 months, coal-fired heating up to 34 months.

Zinc pot outside of bonded 20mm thickfirebrick of steel wire hot galvanizing zinc liquid in the required temperature of the best (46010) in the range of E. Temperature fluctuation is too big, liquid zinc dross in precipitation in the temperature is reduced, not only a large quantity of slag, and the deterioration of the quality of galvanized steel wire, zinc pot erosion intensified. In order to ensure the liquid zinc temperature changes in steel wire galvanizing temperature relatively small, in the design of zinc pot, the molten zinc quantity is 2025 times the amount of hourly production of galvanized steel wire, that is to say 40t molten zinc pot per hour of galvanized steel wire production cannot exceed 2T. heating mode is a key factor affecting the liquid zinc temperature change the general said, call heating fuel (gas) is better than that of heating, coal-fired heating and the worst, but from the economic point of view is just the opposite. Many manufacturers through years of practice that, if the heat source to heat its loss supplement zinc pot consumption and away in the plating steel wire heat during the process and the zinc pot, the heat in a state of balance, can achieve the ideal effect. And the characteristics of coal are heated by fire temperature rises fast, the fire temperature drop quickly hours. Zinc pot heating zone with all the lateral wall of furnace brick with polyester slice or refractory cement will firmly bonded 20mm thick brick, make flame not directly burning zinc pot wall. In order to improve the thermal efficiency of the refractory brick is coated with a layer of black fireproof coating or polyester slicing the pot wall emissivity for more than 0.9, more easily to heat and heat transfer.