Detailed explanation of production method of zirconia ceramic powder

Zirconia ceramic parts are all obtained by ceramic powder molding and ceramic precision machining. The concentration of ceramic powder will directly affect the performance of zirconia ceramics. What are the detailed production methods of powder for you by Kezhong Ceramic Factory?

Zirconia powder is the main component of zirconia ceramics and the main oxide of zirconium. Usually, it is a white odorless and tasteless crystal, which is hardly soluble in water, hydrochloric acid and dilute sulfuric acid. Its chemical properties are inactive, and its properties of high melting point, high resistivity, high refractive index and low thermal expansion coefficient make it an important high-temperature resistant material, ceramic insulating material and ceramic opacifier, and it is also the main raw material for artificial drilling.

Pyrolysis of zirconium oxychloride: zircon and caustic soda are melted at 650℃, and the melt is leached by hot water. Silicon is separated from sodium zirconate in the form of sodium silicate. Then treating with sulfuric acid to obtain zirconium sulfate solution, further removing impurities, adding ammonia water, and precipitating zirconium hydroxide. Adding hydrochloric acid to dissolve zirconium hydroxide to obtain zirconium oxychloride, evaporating, concentrating, cooling, crystallizing, pulverizing and roasting to obtain zirconium dioxide finished product; In addition, zirconium compounds that are easy to purify can be thermally decomposed or oxidatively decomposed to prepare high-purity zirconia.

Colloidal method: silica sol is added into zirconia solution to prepare colloidal solution, which is molded by blowing and drawing, dried and sintered into fibers.

Extrusion method: zirconia sol or zirconia particles and thickener are made into blanks, and the blanks are extruded from the mouth of the machine by hydraulic pressure or the propulsion of a screw cutter to form filaments, and then sintered and solidified to form fibers. The fiber prepared by this method is thicker and the strength of the fiber is lower.

Dipping method: firstly, the viscose filament or the whole fabric is soaked in zirconium hydroxide solution for a long time to swell the viscose fiber, and then the zirconia fiber with certain tensile strength is obtained through pyrolysis and calcination.

Hydrolysis method: using zirconium oxychloride as raw material to hydrolyze to prepare high-purity superfine zirconium dioxide, adding deionized water to 0.2-0.3 mol/L high-purity zirconium oxychloride solution for hydrolysis, and boiling the zirconium oxychloride solution for a long time to continuously evaporate and remove the hydrogen chloride generated by hydrolysis, and then filtering, washing with deionized water, drying, calcining and pulverizing to obtain the product.

High-temperature hydrolysis method: 1mol/L high-purity zirconium oxychloride solution is sprayed into a decomposing furnace at 1000℃, and tiny zirconium oxychloride droplets first evaporate water and then hydrolyze to produce zirconium dioxide. The decomposed zirconium dioxide is collected by cyclone separator, and then washed by acid, water and dried to obtain the product.

Sol-gel method: add alcohol and water to zirconium alcohol [ZrO(C3H7)4], then add catalyst, after fully mixing, start to decompose, leave it to gelatinize and become a viscous liquid, select a proper viscosity, dry it, heat it to 500-1000℃, and fiberize it at high temperature to get the product.

Hydrolysis of alkoxide: using zirconium tetrachloride, ammonia and propanol as raw materials to prepare high-purity ultrafine zirconium dioxide, reacting high-purity zirconium tetrachloride with propanol and ammonia at 5℃ in the presence of benzene solvent to prepare zirconium alkoxide, filtering and separating to remove ammonium chloride, adding water for hydrolysis and precipitation, filtering, drying at not less than 100℃, calcining and pulverizing to obtain the product. Hydrolysis conditions directly affect the particle size, shape and coagulation status of the product. ZrO2 _ 2 with uniform particle size and shape and single structural phase can be prepared by this method.

Zirconium oxychloride (ZrCl2O· 8H2O) recrystallizing with hydrochloric acid or methanol, and calcining at high temperature to obtain the finished product.

Tetraalkoxy zirconium is distilled and purified, and its vapor is decomposed at 350 ~ 500℃ to obtain the finished product.

Zirconium tetrachloride is distilled and purified, and its vapor reacts with excess oxygen at 1200℃ to obtain zirconium dioxide.

Zirconia can be used to prepare powders with high purity, good dispersibility, ultrafine particles and narrow particle size distribution, and zirconia ceramic products can be filled with powders made of zirconia.

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