42results about How to "Save on drying costs" patented technology

The invention discloses a production method for a large grain size cryolite, which is characterized in that Bayer process concentrate solution, caustic soda, and hydrofluoric acid are used as raw materials, and the proportion of raw materials is represented in the equation that Al: Na: F equals to 1:1.8-3:5-6; when compounding, the caustic soda is added into the Bayer process concentrate solutionwith a temperature of 90-95 DEG C, and mixed evenly to obtain the composite solution; then, the composite solution and hydrofluoric acid are gradually added into a synthesis tank, and the material feeding and agitation are carried out in the meantime, the reaction temperature is maintained between 85 and 95 DEG C, and the PH value of the reaction solution is smaller than or equal to 2; after feeding materials, the mixture undergoes an ageing process for 20 to 30 minutes; finally, the slurry is filtered, the filter cake is dried until the water content drops below 0.2%, thus acquiring the finished cryolite. The production method has the advantages that: as wet method is adopted during the production, the reaction is conducted under normal temperature, the process is simple, and easy to operate and control; the heat source is derived from the reaction heat, and the need to add a heating apparatus is avoided; by adjusting the parameters, such as the reaction temperature, PH value and ageing time, the product D50 grain size can be increased by more than 10 Mu m compared with the prior art up to 26-30 Mu m; the molecular ratio of NaF to AlF3 is adjustable, thus meeting the demands of electrolytic aluminum industry.