Mullite Composite bricks for Basic rotary kiln ( P

Mullite Composite Bricks for Alkali Rotary Kiln Patent No.200510069172.5ItemsUnitSpecification12Al2O3≥%7565RefractorinessoC17901790Bulk densityg/cm32.65 2.75 Refractoriness under load≥oC15501650Linear change after heating, 1450X2h%±0.3±0.4Apparent porosity≤%2019Cold crushing strength≥Mpa6080Heat and shock stability (1100 water cooling)times3050Alkali resistancegoodgoodApplication1:Sintering interim cooling zone 2:Cooling sintering interim zone Mulite Composite Bricks for Alkali Rotary Kiln is a patented up-to-date product in China, which is developed by our Chief Engineer Mr. Fu Zongde, mainly used as burning zone and transition zone linings of cement rotary kiln. The product is especially designed for the cement rotary kiln, has some significant advantages compare with other products.1. Environment Protection: The researches was made against the pollutions that results from the long term use of direct bonded Mg-Cr bricks in cement rotary kilns. Magnesia-chrome brick contains metal oxides of trivalent chromium, which reacts with the alkaline salt in the materials under high temperature and form hexavalent chromium compounds, which is a kind of water-soluble carcinogenic material, pollutes the environment seriously and harmful to the human health. Cr +6 content is 0.1% 0.5% in the used Mg-Cr brick leftovers, with an average 0.3%, the main harmful substance is K2CrO4. K2Cr2O4 (potassium chromate), which is a weak oxidizing compounds with higher chemical durability. It is very difficult to be reduced to non-toxic trivalent chromium after dissolving into the water. On many occasions these compounds containing Cr +6 are be stable in nature, which cause to the long-term and persistent environmental pollution. It has been a pressing task to replace the kiln materials with non-chrome materials, along with the formulation of environmental safety regulations. This product does not contain any environmental pollution material and harmful compounds, is the ideal choice to replace Mg-Cr bricks. 2. Service Result: The products were developed according to the features of producing mechanism and industrial environment of cement rotary kilns.There are three main factors of the lining bricks destruction when the cement rotary kiln in under operation, according to the different industrial environment. The first one is chemical erosion, including calcium, potassium, sodium and sulfur. The surface layer of the lining bricks are being continually basified, shortened under long-term alkaline environment. The second is thermal shock damages caused by sudden changes of temperature. Spalling happens on the kiln lining as it faces to thousands of fluctuations between 200 and 400 everyday when the kiln is under operation, which damages the kiln lining. Thirdly, the mechanical vibration and charging smashing, which causes the rubbing damage in operating of rotary kiln. The original technologies of this patented products come from the function complementary theory performance of multi-phase composite, which changes the traditional theory of high RUL leads to low thermal shock resistance. The bricks have passed a sequence of tests & comparisons during the stages of experimentation and the parameters of damaging factors were marked from the destructive tests. Based on a number of experimental tests, the normal production batches were carried out for testing the reliability of the bricks. Series of tests from LIRR and other national refractory authorities shows that the quality is reliable and stable.Testing data proves the specialty of the bricks as following,- High RUL, above 1700, which guarantees the stable shape of the bricks under high temperature, and enable the bricks to stand against erosion and rubbings.- The excellent thermal shock resistance, which is key specialty of this brick. The average is 50--80 cycles under 1100 /water cooling, which is also an international leading at present. .- The good anti-alkali property. The crushing strength of the bricks still higher than 60 Mpa after the alkali-damaging tests. In addition to the above excellent physical and chemical properties, the mullite composite brick can make a good kiln coating during the service, the coating is dense and not breaking off as normal. These characteristics make the bricks to achieve a long service life under the condition of high temperature, high erosion, high thermal shock, and high mechanical vibration. 3. Energy-saving: Aims to save cost for cement manufacturers. The conservative service life of the product is 10-12 months. Services life was improved more than 2 times than others bricks, maintenance was reduced, and the loss of rebuilding, construction and purchasing Mg-Cr bricks again were cancelled directly. Meanwhile it brings down the frequency of kiln close down for kiln lining replacement, and improves the enterprise productivity efficiency. Based on an overall consideration, the products could save huge cost for enterprises, which makes it become the first choice for cement and metallurgical industry. It will change the history of the cement rotary kiln relying on Mg-Cr, Mg-Al Spinel bricks, and set off a national even global revolution in the cement kiln bricks. Application: "Mulite Composite Bricks for Alkali Rotary Kiln" have achieved excellent results in dry-process cement kiln and wet-process cement rotary kiln. Reference list as attached Summary: This product is superior to others in various respects:1. The service life of rotary kiln is longer than other products, reduces the production cost and improves the cements quality obviously. 2. It is an environment friendly products, not harmful to the environment and human health; 3. More fuel could be saved since the kiln body temperature would be 50 degrees lower when lined by this brick;4, we are making an international brand, well arranged after-sale technical service will make the service life a substantial increase in operation.