<p>Rolling slurry is produced from rolling steel as iron oxide particles moistened with a mixt. of water and lubricating oil, and obtd. by sedimenting or filtering cooling water from steel rolling plants to modify the colour of brick prods., esp. wall bricks and roofing tiles. Colour-modified brick products produced from crude clay are also claimed, in which 5-50 (pref. 5-20) % the above rolling slurry is mixed with the crude clay before drying and calcining.</p>
