The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 18, 1984
Filed:
Dec. 27, 1982
Padraic S O'Neill, Dublin, IE;
Charles W Weston, Prairieville, LA (US);
Kyle D Clevenger, Lakeland, FL (US);
Jesse S Chang, Baton Rouge, LA (US);
Agrico Chemical Company, Tulsa, OK (US);
Abstract
An economical process for treating the acidic pond water to be used in the internal grinding circuit of a wet process phosphoric acid plant. Water is added to a quantity of a hydratable calcium compound, such as quicklime, to form a slaked lime slurry. A sufficient quantity of the slaked lime slurry is reacted with the acidic pond water to obtain a low fluoride solution having a fluoride content less than about 300 ppm and a pH in the range from about 2.0 to about 3.0, preferentially in the range 2.6-2.8, whereby calcium fluoride is precipitated. The precipitate bearing low fluoride solution is then clarified and the precipitate removed as underflow from the clarifier and transferred to the gypsum pond. In the preferred embodiment, the clarified low fluoride water is fed to the ball mill and is mixed with the phosphate rock being crushed. Removal of fluoride from the pond water solution reduced the 'blinding effect' of the fluoride and permits the calcium carbonate in the phosphate rock to neutralized the acidic pond water to minimize corrosion in the mill and elsewhere in the plant. The resulting slurry from the ball mill is about 55% to 65% solids and ranges in pH range from about 5.0 to about 5.5. The phosphate rock slurry is then passed through a hydroclone circuit where the larger (heavier) particles are removed for recycling to the ball mill and the remaining lightweight particles in the rock slurry are processed by phosphoric acid plant.