refractories
A larger ladle refractory amount of silica brick and clay. Brick containing more than 93% SiO2 siliceous products, raw materials used are silica, silica brick and other waste. Brick acid-resistant slag erosion ability, but are vulnerable to erosion of basic slag, its high load softening temperature, close to its refractoriness, the volume does not shrink after repeated firing, and even a slight expansion, but anti-refractory abrasive
Poor thermal shock resistance. Mainly used for coke oven silica brick, glass melting furnaces, steel furnaces and other acidic thermal equipment. Bricks containing 30% to 46% alumina, refractory castable refractory clay it as the main raw material, refractoriness 1580 ~ 1770 ℃, thermal shock resistance, weak acid belongs refractory to acid slag have corrosion resistance, widely used, The current production capacity is the largest category of refractories.
Neutral refractory
High aluminum products in the main crystal phase is mullite and corundum, corundum content increases with increasing alumina content and containing more than 95% of refractory company alumina corundum products is a wider use of high-quality refractory materials. Chrome brick mainly chrome ore as raw material, the main phase is chromite. It slag corrosion resistance, but poor thermal shock resistance, high temperature load deformation temperature is low. Chrome ore and magnesite in different proportions of chrome magnesia brick made good thermal shock resistance, mainly used for basic flat roof tiles. Carbonaceous products are another neutral refractories, according to the carbonaceous feedstock composition and mineral products, divided into carbon bricks, graphite products and silicon carbide products categories. Carbon brick with high-grade petroleum coke as feedstock, plus tar, bitumen as a binder, at 1300 ℃ firing isolation under atmospheric conditions. Graphite products (except natural graphite outside) by 2500 ~ 2800 ℃ graphitized carbonaceous material obtained in an electric furnace. Places carbide silicon carbide products as raw materials, plus clays, binders such as silica calcined at 1350 ~ 1400 ℃. Silicon carbide can also be added to the silicon powder in an electric furnace under a nitrogen atmosphere castable is made of silicon nitride - silicon carbide products. Refractory Abrasives coefficient of thermal expansion of the low carbon products, high thermal conductivity, good thermal shock resistance, high temperature strength. fire bricks Long-term use at high temperatures do not soften, without any acid-base erosion, good salt tolerance, but also from metal and slag wetting, lightweight, high-quality refractory materials. The disadvantage is easily oxidized at high temperatures, it should not be used in an oxidizing atmosphere. Carbonaceous products are widely used in high temperature furnace lining (hearth, hearth, the lower part of the furnace body, etc.), non-ferrous metal smelting furnace lining. Graphite products can do the reaction vessel and petrochemical lined autoclave. Silicon carbide and graphite products can also be made with gold and copper smelting crucible with light alloy.
Basic Refractories
With magnesium products as a representative. It contains magnesium more than 80% to 85%, based on periclase main crystal phase. The main raw materials to produce magnesia brick of magnesite, seawater magnesia extracted from the sea by high temperature calcination of magnesium hydroxide) and the like. Alkaline slag and iron slag has good resistance. Polycrystalline mullite fiber melting point of pure magnesium oxide up 2800 ℃, therefore, magnesia brick refractoriness than the clay bricks and brick are high. Since the mid-1950s, the use of open hearth furnace and basic oxygen converter steel roof, basic refractories production increasing adoption, clay and silica brick production is declining. Basic Refractories mainly used open hearth, oxygen converter, electric furnace, non-ferrous metal smelting as well as some high-temperature thermal equipment.
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