Sintered Zircon Bricks

The main raw material of sintered zircon bricks is zircon concentrate sand, which is made by adding a small amount of plastic clay or other organic binders, and going through processes such as batching, pressing, calcining, crushing, mixing, molding and firing. The calcination and firing temperatures generally do not exceed 1600°C, and the firing process can usually be completed by keeping warm for a long time at 1400°C. This material is suitable for masonry of steel ladle linings, high-temperature induction furnace linings, aluminum smelting furnace bottoms, and can also be used for easily damaged parts of glass tank kilns. Sintered zircon bricks are also widely used in key parts of kilns in the steel, petrochemical, fertilizer, nonferrous, electronics and other industries because of their high temperature resistance, high compressive strength, strong high temperature erosion resistance, good wear resistance, slag resistance and thermal shock resistance, as well as a small thermal expansion coefficient and erosion resistance.

 

Manufacturing process of sintered zircon bricks The raw materials are prepared by the method of producing sintered refractory products, and the green body is pressed and sintered at high temperature to produce zircon-containing sintered bricks. Granulation, mixing, machine pressing or extrusion can also be used to form the rough blanks, and the clinker sintered at high temperature is used as aggregate. The clinker fine powder is used for batching, mixing, forming, drying and sintering to produce sintered zircon bricks.

Sintered zircon bricks are refractory products fired with zircon as the main raw material. Zircon is the only compound in the ZrO2-SiO2 system, and its chemical formula is ZrSiO4. The theoretical chemical composition of zircon is ZrO267.2%, SiO232.8%.

Performance Zircon bricks have excellent properties such as high temperature resistance, good thermal shock resistance, resistance to slag erosion and resistance to glass liquid erosion. Sintered zircon bricks work stably in an oxidizing atmosphere and do not react chemically with molten metal.

Raw materials Zircon ore coexists with quartz, ilmenite, garnet, monazite and rutile, so zircon ore must be beneficiated and prepared into zircon concentrate before it can be used. Zircon ore is re-selected to remove quartz and vein quartz minerals; ilmenite, garnet and monazite are removed by magnetic separation; and rutile is removed by flotation to obtain zircon concentrate. Zircon concentrate can be divided into three grades: 65, 63 and 60 according to the content of ZrO2.

When zircon is heated to a certain temperature, it can be decomposed into cryptocrystalline ZrO2 and amorphous ZrO2. Due to the different purity and impurities of zircon, the particle size of raw materials and the insulation time, the decomposition temperature of zircon is also different. Its decomposition temperature range is 1540~2000C. When zircon is heated at 1600℃ for 2h, only a small amount of zircon decomposes; when heated at 1750℃ for 2h, the decomposition rate of zircon is 50%, and when heated to 1900℃~2000℃, the decomposition rate can reach 100%. The presence of impurities such as Al2O3 and Ca0 reduces the decomposition temperature of zircon. Therefore, when preparing zircon clinker, its pre-burning temperature must be lower than the decomposition temperature of zircon (1540℃).

Uses Zircon bricks can be used as large bricks for the bottom of glass tank kilns and upper structural materials. In the field of metallurgy, zircon bricks can be used as linings for steel ladle, continuous casting nozzles, etc.

Zircon refractory products with an apparent porosity of less than 5% fired with zircon (ZrSiO4) as the main raw material. Dense zircon bricks have good resistance to glass erosion and are mostly used as furnace materials for glass melting furnaces.

Performance Dense zircon bricks have good mechanical strength, thermal shock resistance and resistance to glass erosion.

Production process The raw material used to make dense zircon bricks is zircon concentrate. Zircon is associated with monazite and contains trace amounts of radioactive elements such as Th. Therefore, when zircon concentrate is used to produce dense zircon bricks, it must be tested for radioactivity intensity. If the specific radioactivity intensity exceeds the specified range, appropriate protective measures must be taken.

Dense zircon bricks can be made by mud casting process and semi-dry production. Slurry casting process: The zircon concentrate powder is first wet-ground to prepare a finely dispersed slurry with a particle size of 2~5μm, then pressurized and cast, and fired at about 1600℃ to produce a dense zircon brick with an apparent porosity of less than 5%.

Semi-dry production process: using activated zircon fine powder as raw material, adjusting the acidity of the mud and adding an appropriate amount of binder, and then forming, drying and firing to produce dense zircon products.

Uses Dense zircon bricks can be used for the wall of the melting pool of alkali-free glass ball kiln, the upper wall of the flow hole, etc., and its resistance to glass liquid corrosion is better than that of quartz large bricks. When used at the bottom of the alkali-resistant glass fiber tank kiln, the brick body has no obvious corrosion and the pollution to the glass liquid is small.

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