| 摘要 |
<p>Zinc muds or sludges containing cadmium sulphide resulting from the reduction of oxygen containing compounds with zinc dust are dissolved in sulphurous acid, the solution of zinc bisulphite formed is separated from impurities, the solution heated to precipitate the monosulphite, and the latter roasted to obtain substantially pure zinc oxide. The sludges may be obtained by reducing formaldehyde solutions of zinc hyposulphite or zinc bisulphite with zinc dust and treating the precipitated product with alkali, or by reducing sulphurous acid with zinc dust and converting the impure hyposulphite solution formed into alkali hyposulphite by means of alkali, or by the reduction of nitrobenzol by zinc dust.</p> |
