METHOD OF PRODUCING CORUNDUM CERAMICS Russian patent published in 2020 - IPC C04B35/111 C01F7/02 B82Y40/00 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical engineering, particularly to methods of producing corundum ceramics, and can be used in radioelectronic and electrovacuum equipment, as well as in medicine for making prostheses and implants. Preparation of aqueous suspension from layered double hydroxide of magnesium and aluminum Mg₄Al₂(OH)₁₂CO₃⋅3H₂O and hydrated aluminum oxide Al₂O₃⋅nH₂O, where n>3, with additional introduction of ammonium carbonate in amount of 3–8 mol per 1 mol of Al₂O₃. Layered double hydroxide of magnesium and aluminum Mg₄Al₂(OH)₁₂CO₃⋅3H₂O is obtained by mixing crystalline hydrate of chloride or nitrate of magnesium and aluminum with ammonium carbonate. Suspension is stirred at temperature 70–120 °C and L:S=10–18 for 2–6 hours to form aluminum and ammonium hydroxocarbonate precipitate, which contains finely dispersed powder layered double magnesium and aluminum hydroxide. Precipitate is separated and dried at 100–120 °C to ensure constant weight, after which heated to temperature of 1,100–1,200 °C and held for 1.0–1.5 hours to obtain a ceramic-forming mixture which is subjected to molding and annealing.

EFFECT: claimed method allows to reduce the energy consumption and the number of transactions and to receive corundum ceramics 3_95–3_98 g/cm³ density when using commonly available starting components.

3 cl, 4 ex