Tangshan Tangbao Refractories Co., Ltd.
Address：Beijiadian Third Street, Guye District, Tangshan
The development trend of amorphous refractories is to develop dry materials which can be mixed with water. This dry mix can be stored for a long time without affecting its quality. When used, the amount of water added can be adjusted according to the forming method adopted, and the rheological state of the sludge after mixing can be controlled by adjusting the amount of water added. At present, the high alumina amorphous refractories used in Russia mainly consist of slurry containing liquid binder (orthophosphate), but their shelf life is very short (2-3 months). Moreover, the use of phosphoric acid binder in sludge can also produce unsatisfactory results because phosphorus inclusions can contaminate the metal melt. The use of refractory clay as plasticizer in high aluminium mixtures produced in Russia is also unsatisfactory, because this will significantly reduce the fire resistance of the final product. For these reasons, it is urgent to develop high alumina dry materials without phosphoric acid and refractory clay. Researchers at the St. Petersburg State Institute of Technology in Russia have developed a new type of high aluminium dry material which can be formed by vibration. The plasticizer used in this dry material is a dry substance with a dosage not exceeding 0.03%. It can make the fine powder part of the dry material plasticity without using fireproof clay. The choice of plasticizer depends on the composition and quantity of fine powder used. The fine powder used in dry material can be alumina powder, fused corundum and high alumina clinker. Usually the same amount of fused white corundum, grinding grade fused corundum and mullite corundum clinker (the maximum particle size is 20.1 and 20 um, respectively) can be plasticized when the water content is 24%. However, only 9.5% of the water is needed after using the developed plasticizer. After using these fine powders and plasticizers, it can be ensured that the developed high alumina mixture still has good construction performance when the water content is not more than 3%. The binder used in high alumina dry materials is a composite binder, which is composed of dry organic mineral composition. When preparing vibrating forming slurry, it is gelatinization tendency when dissolved by water, and its pH value is kept in the range of 4~6 or 8~10. The choice of plasticizer and binder for vibration castable in acidic or alkaline water medium is different. The content of fine powder is not more than 25%, the volume density after baking is more than 3.0 g cm-3, the apparent porosity after drying is not more than 17%, the compressive strength is greater than 90 MPa, and the permanent line change rate is not more than 0.2%.
According to the research results, a new method of high aluminium dry material which can be formed by vibration and vibration casting has been developed.