Continuous alumina precipitation - using partial recycling to prevent premature carry over of fine particles

摘要

In operating series-connected precipitation chambers each comprising a mixing tube, a portion of the liquor overflowing the edges of the mixing tubes is conducted, by means of the entry section of the outlet duct and the carry-over duct, into the inlet regulation chamber of the next vessel. From here a portion of the liquor flows back through the level regulation duct into the preceding vessel. Specif. the outlet and carry-over ducts have a forward, downwards inclination and the level regulation duct a reverse inclination. The upper portion of the liquid is continuously recycled, thus preventing carry over of fine particles from one stage to the next, when the plant is operating at a high rate.