What are the specifications of refractory kilns ?
Since the coefficient of thermal expansion of the basic brick is large, expansion rate is about 1-1.2% under 1000 ℃ The literature indicates that: "Under the condition that the temperature was raised to 1000 ℃ and stress in brick lining is relaxed, 300N / mm2 of compressive stress can be produced, which is equals to ten times structural strength of ordinary magnesia chrome brick, six times structural strength of magnesia chrome brick, dolomite brick and spinel brick, so any basic bricks can not afford, " the paper also pointed out that " heat expansion rate of kiln body can partially compensate for expansion rate of the inner lining of 0.2% -0.4%, which is 1/3 of thermal expansion rate of ordinary magnesia-chrome brick under 1000 ℃. However, it occurs under thermal equilibrium conditions. Thereby, the kiln should be dried slowly, allowing the temperature of the kiln body to go up slowly, thus the role of compensation can be played. " This is the key to using the basic brick. " Procedures of refractory for cement kiln "( tentative one) has clearly regulated baking and cooling of the kiln in the first section of the fifth chapters. In the heating process, in particular when the temperature is in the range of 300-1000 ℃, heating rate must be less than 60 ℃ / h. This is very clear in theory but it is difficult to implement.
Rotating equipment is widely used in mechanical, physical or chemical treatment of solid materials in building materials, metallurgy, chemical and environmental protection industry. Such equipment is called rotary kiln. The best materials are magnesia-chrome bricks, unfired magnesite-chrome bricks, silmo bricks, magnesia-alumina spinel bricks, magnesia calcium zirconate bricks, iron magnesia bricks and castables.
There several points need to be noted ① selection of body material. The refractory lining of the front kilneye turns gelid and hot rapidly and frequently, so the temperature is in the range of 800 ℃ ~ 1250 ℃, allowing it to withstand wear of the cement clinker and corrosion of the cement base. The body material of castable refractory must be chosen according to its service conditions, in order to ensure that it is cheap and easy to use. ② the selection of admixture. Shapeless refractory materials are typical in-situ reaction refractories. Therefore choosing admixtures is very important and must ensure workability, baking performance, and excellent material properties. Admixture for Kiln refractory castable includes dispersants, accelerators, plasticizers, sintering agent, bulking agent and antidetonant. Materials of sintering agent are animate clay, zirconite, titanium dioxide and Peng compounds. Such substances produce a certain amount of mullite crystals, zircon phase, titanium aluminate crystal and inconsistent melting compounds (2Al2O3 ? B2O3), etc. under the operating temperature and in situ reaction. They are accompanied by volume expansion and microcracks, enabling it to compensate for the sintering shrinkage, so that the casting material can have sintering strength, corrosion resistance and good thermal shock resistance. In summary, the refractory castable material for the rotary kiln shall be determined in accordance with its service conditions. It is recommended that clients should also communicate with technical personnels and sales staff about some facts of the rotary kiln when buying it, so that they can get the satisfying rotary kiln.
