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The above Directive specifies that as of the end of 2004 cement and cement-containing preparations must not contain more than 0.0002 % (2 ppm) soluble chrome-VI since that can cause severe allergic reactions when in contact with the skin for longer periods. Hence, over 350 cement plants throughout Europe had to be upgraded in a hurry. Iron-II and tin-II sulphates reduce the chrome content. With re-ducing agents and water chromate-VI is converted into antisoluble chromate-III hy-droxide harmless to the skin. 0.3 to 0.5 % tin/Fe(II) sulphates must be added. The MechaTron®, designed for 0.5 to 600 t/hr, offers all requisite properties. There are different MechaTron® variants available, depending on material properties and feed rates. For the sluggish Fe(II) sulphate there is the Coni-Flex® variant with flexible dis-charge hopper, for the even more difficult to handle tin sulphate Coni-Steel® with in-ternal agitator is the choice. MechaTronâ systems, equipped with DISOCONT® weighing electronics, are suitable for volumetric and gravimetric feeding. With more than 450 feeders supplied, Schenck has an impressive market leadership.
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