Appts. for forming sewage treatment silicate prods. - includes mixing tube with static high shear device

摘要

Stable, aq. dispersion of a complex alkali metal-Al-silicate is formed in an appts. comprising a mixing tube having >=2 inlets and an outlet. The bulk of the water is fed into a second and a sol. Al salt soln. is fed either through the first or a third inlet. The streams from each inlet pass along the tube in a helical path due to a stationary device in the tube and the aq. dispersion is recovered at the outlet at a pressure at 40 psi lower than the water inlet pressure. Prod. dispersion, which has a pH 3-7.5 (depending on the silicate content), contains up to 5% silicate (calc. as SiO2) and is sol. in HCl and useful as a coagulant aid in treatment of industrial and sewage effluent. Appts. provides adequate shear mixing of solns. without need for moving parts or fine controls in throughput rates etc.