| 摘要 |
<p>1531561 Iron oxide pigment SOC DE PRAYON 2 Jan 1976 [3 Jan 1975] 00037/76 Heading C1A An iron oxide pigment based on alpha-Fe 2 O 3 is produced by calcining basic iron sulphate and/or jarosite at a temperature of from 600‹ to 800‹ C. with an oxygen excess in the gaseous phase for a period from 2 to 240 minutes so as to decompose the basic iron sulphate and/or jarosite in an incomplete manner and to obtain in the calcined product an iron-bonded sulphur content of more than 0À6 wt. per cent, and dissolving out the not decomposed iron sulphate together with any other soluble sulphates present in the starting material, e.g. ZnSO 4 , by lixiviating the calcined product with water and separating by a liquid-solid separation method the resulting aqueous solution of watersoluble compounds from the water-insoluble solid residue, which provides the pigment.</p> |
