BENEFICIATION OF CREEK CALCAREOUS PHOSPHATE ORE USING ACETIC-ACID SOLUTIONS

The enrichment of the low-grade natural phosphate ores from Epirus are a (Greece) by selective dissolution of calcite using dilute acetic aci d and the optimization of this process studied by kinetic and textural analysis is given. The used conditions of the dissolution were the re action time, stirring speed, acetic acid concentration, temperature, p article size fraction, and stoichiometry. The specific surface area, p ore size distribution, and SEM photographs were used for textural anal ysis. We found that the more effective experimental conditions led to a concentration of about 31% of P2O5 or 95% of francolite. The dissolu tion of calcite spaces took place in two steps. The first step was att ributed to the dissolution of liberated calcite particles and/or space s on the particles, and the second one was attributed to the dissoluti on of calcite in the interspaces between phosphopeloids. A rate equati on of the general form ln[1/(1-X)] = kt(m) was found to represent thes e data.