Anionic Flotation of Florida Phosphate
In this study, the applicability of an anionic rougher-cleaner process on present and future ores from Florida as compared to the Crago process is evaluated.
Six commercially available anionic collectors were selected for evaluation. Three of the anionic collectors were fatty acid type reagents obtained from Florida reagent vendors. The fourth anionic collector, a petroleum sulfonate, was obtained from a domestic vendor. The fifth and sixth anionic collectors, an organophosphoric acid and an N-substituted sarcosine, were obtained from European vendors.
Bench scale flotation tests were conducted to evaluate the six anionic collectors on 14×35 mesh, 35×150 mesh, 14×15 mesh, and 28×150 mesh flotation feed obtained from present ore. After the critical variables had been identified, another series of tests was conducted to optimize the anionic rougher-cleaner process performance. A parallel series of tests were conducted to optimize the Crago process performance.
Relative to the Crago process, the anionic rougher-cleaner process gave lower grade concentrate, higher phosphate recovery, and lower reagent cost for 28×150 mesh feed. Chemical analyses indicate the anionic concentrate is a suitable feedstock for a commercial acidulation plant.
The test program for 28×150 mesh flotation feed obtained from future ore was essentially identical to that described previously for present 28×150 mesh feed.
Relative to the Crago process, the anionic rougher-cleaner process gave lower grade concentrate and lower reagent costs. Neither process was effective in rejecting carbonate minerals from the concentrate. The carbonate contaminants would not be acceptable feedstock for commercial acidulation plants.