Waste water purification silica

Alumina trihydrate (ATH) is made from waste generated by the almninum metal purification process. It has high brightness but low refi active index. At low levels of substitution for Ti02, 25% or less, optical properties can be maintained. Like the synthetic silicas, ATH can be used as a paper brightning pigment when opacity is not as important. ATH is used in NCR (no carbon required) papers where it favorably affects the special dyes used in the paper. ATH is also known for its flame retardant properties. ATH retards bmming by the release of water at rather low temperatures. It is added to impart flame retardance to certain specialty papers. 

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