Anionic polyacrylamoide liquid Nalco 85700 or Cytec TF-9000 used for alumina hydrate settling process
Nalco 85700 or Cytec TF-9000 is based on DEXTRAN branched with polyacrylate polymer. This polymers are used in Alumina hydrate settling.
Anionic polyacrylamide can also be used in the alumina hydrate settling process in alumina production. The alumina hydrate settling step is a
crucial part of the Bayer process, which is used to extract alumina from bauxite ore. Here's how anionic polyacrylamide is applied in this context:
Bayer Process Overview: In the Bayer process, bauxite ore is first ground into a fine powder and then mixed with a hot, concentrated solution of
sodium hydroxide (caustic soda) in a highpressure digester. This process dissolves aluminum compounds from the bauxite, creating a sodium
aluminate solution.
Precipitation of Alumina Hydrate: To precipitate alumina hydrate from the sodium aluminate solution, the pH of the solution is reduced by adding
an acidic solution or carbon dioxide. This leads to the formation of aluminum hydroxide or alumina hydrate as a solid precipitate.
Solid-Liquid Separation: After the precipitation step, the mixture contains solid alumina hydrate particles suspended in the liquid phase. Liquid anionic
polyacrylamide is added to the slurry to aid in the separation of the solid alumina hydrate particles from the liquid.
Flocculation and Settling: Anionic polyacrylamide acts as a flocculant in this step. It helps agglomerate the fine alumina hydrate particles into
larger flocs, which settle more rapidly in sedimentation tanks or thickeners. This separation process allows for the recovery of alumina hydrate.
Filtration: In some cases, the settled alumina hydrate slurry may undergo further dewatering and solidliquid separation through filtration processes
to achieve a higher concentration of alumina hydrate.
Liquid anionic polyacrylamide is used in this alumina hydrate settling process to improve the efficiency of solidliquid separation, reduce energy
and chemical consumption, and achieve a higher yield of alumina hydrate.
The specific dosage and application of anionic polyacrylamide can vary depending on the characteristics of the alumina hydrate slurry and the
equipment used in the process. Working with experts in chemical engineering and alumina production is crucial to optimize the use of anionic
polyacrylamide for your specific application while adhering to safety and environmental regulations.