| 摘要 |
<p>1532468 Iron oxide black pigment BAYER AG 20 April 1976 [24 April 1975] 15875/76 Heading C1A An iron oxide black pigment of the magnetite structure is prepared by precipitating iron oxide hydroxide in an alkaline medium with ferrous hydroxide in the presence of from 0À05 to 5 wt. per cent based on the end pigment of at least one inorganic ionic compound of the metals Cu, Ni, Al, Cr, Ti, Zr and/or V and recovering the pigment formed. The iron oxide hydroxide may be prepared by partial precipitation of the iron from a ferrous salt solution in the presence of an alkali metal or alkaline earth metal hydroxide followed by oxidation at acid pH. The ferrous hydroxide may be prepared by then precipitating the remaining ferrous content of the ferrous salt solution with further alkali metal or alkaline earth metal hydroxide. Alternatively the iron oxide hydroxide and ferrous hydroxide may be prepared separately.</p> |
