| 摘要 |
<p>1381036 Nickel powder; Ni ammines LE NICKEL 29 Aug 1972 [14 Sept 1971] 40086/72 Heading C1A High purity nickel powder with predetermined physical characteristics is produced by reacting gaseous ammonia or an aqueous solution of ammonia at a temperature between 20‹ and 40‹ C. with an aqueous solution of nickel chloride containing at least 50 g./l. of nickel, the resulting precipitate of hexammine complex of nickel chloride being separated by filtration and submitted to drying at a temperature higher than 100‹ C. in order to convert it, at least partly, into a diammine complex of nickel chloride with release of ammonia, and said diammine complex being reduced by hydrogen at a temperature between 450‹ and 1000‹ C. The physical characteristics of the obtained nickel powder may be controlled by controlling the temperature at which the diammine complex is reduced by hydrogen. The gaseous ammonia or aqueous solution of ammonia may be reacted with the nickel chloride in an amount of at least twice the stoichiometric amount necessary for the production of the hexammine complex of nickel chloride which may be centrifugally dried prior to drying above 100‹ C. and the ammonia released in this drying process may be recycled to react with fresh amounts of aqueous nickel chloride. The ammonium chloride produced during the reduction step may be dissolved in the mother lye of the filtration step and reacted with lime to release ammonia which is also recycled to react with fresh amounts of aqueous nickel chloride. The precipitated hexammine complex of nickel chloride may also be reduced directly by hydrogen at 450‹ to 1000‹ C. without the intermediate drying step.</p> |
