METHOD OF PREPARING SIALON POWDER Russian patent published in 2010 - IPC C04B35/599 C04B35/65 

FIELD: chemistry.

SUBSTANCE: invention relates to methods for synthesis of organic compounds, particularly sialons, which can be used to make corrosion-resistant refractory objects and high-strength metal working tool. The reaction mixture is thermally processed via local initiation of reaction in layer by layer burning mode at nitrogen pressure of 2-20 MPa with subsequent nitration at nitrogen pressure of 0.1-10.0 MPa for 0.5-1.0 hours. The cooled product is crushed and subjected to magnetic separation, after which it is treated with a 15-30% solution of hydrochloric acid. To obtain sialon powder of general formula Si_6-zAl_zO_zN_8-z, where z=3, the mixture is prepared from ferrosilicon (base), topaz concentrate (0.5-2.0 wt %) and pre-nitrated ferrosilicon (40.0-59.5 wt %). To obtain sialon powder of general formula Si_6-zAl_zO_zN_8-z, where z=1.31 and 3, the mixture is prepared from ferrosilicon (base), corundum (20.0-30.0 wt %), and additionally, if necessary, pre-nitrated ferrosilicon (20.0-25.0 wt %) and ammonium fluoride (0.5-1.0 wt %). The obtained powder is a composition which consist of sialons of composition Si₃Al₃O₃N₅ and Si_4.69Al_1.31O_1.31N_6.69. Residual content of iron is not more than 0.12 wt %.

EFFECT: reduced cost of powder and recycling industrial wastes.

7 cl, 1 tbl, 3 ex