| 摘要 |
Building materials such as concrete can be colored by a black pigment which consists essentially of manganese ferrite of the composition Mn1+xFe2-xO4 with a spinel structure wherein x has a numerical value from -0.1 to 0.1 and the pigment is prepared by a process wherein a) soluble manganese (II) salts and soluble iron(II) salts are precipitated from a solution of metal salts by reaction with alkaline precipitating agents in an approximately stoichiometric ratio, b) the precipitate from a) is reacted with an oxidizing agent to form a pigment, and c) the pigment is filtered, washed, dried and ground.
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