Essentially the same procedure as described above for feldspar treatment through Step 4 or Step 5 is used to treat glass sands, depending on the minerals present in the sand deposit. If feldspars are present and are to be recovered, the tailings from Step 5 are the final glass sand product. In the absence of economic feldspar values, the tailings from Step 4 would be the final silica product. Cytec's AERO 866 and AERO 869 promoters are widely utilized in such glass sand flotation operations globally, and the entire AERO 800 promoter series should be evaluated to determine the optimum collector for a particular sand deposit.
At some glass sand operations, naturally-occurring organic colloids may make a fatty acid float of the iron-bearing minerals preferable. After desliming, the pulp is conditioned at high solids with one of the AERO 700 promoters series such as AERO 704 or AERO 726 and soda ash or caustic soda to pH 8-9. Fuel oil may be added to the flotation circuit for froth control.