Optimal Depressants and Collector Dosage in Fluorite Flotation Process Based on DoE Methodology

Abstract

Alternative processes have been proposed for selective separation of fluorite and gangue minerals (carbonates and silicates) present in fluorspar ores. Calcination and gravity separation processes are methods that have low efficiency and high cost. Flotation is a chemical process that becomes important when high ore grades are required; however, the selectivity is inhibited by the superficial similarity of the chemical composition of minerals. Accordingly, interactions between dissolved ionic species of fluorite, carbonates, and silicates with some reagents under determinate conditions obstruct the flotation process. In order to optimize the flotation process of a Spanish fluorite ore, this research uses a mathematical model. In this study, the variables were the dose of potato starch, quebracho tree, white dextrine, oleic acid, and sodium silicate. On the other hand, the factors studied were the law of carbonates, silica, and fluorite, in addition to the metallurgical recovery of fluorite. The statistical technique of factor analysis that relates the variables and factors allowed to the optimization of the reagent dosage. Maximum metallurgical recovery was achieved without sacrificing the fluorite grade. The mathematical model adjusts satisfactorily to the results with a correlation coefficient of 91.58% for metallurgical recovery and 98.51% for fluorite grade. Optimizing the process 60.45% of metallurgical recovery and 68.99% of fluorite grade are achieve in the roughing step, using a dosage of 1.68 g·kg−1 of potato starch, 0.86 g·kg−1 of quebracho tree, 1.25 g·kg−1 of dextrin, 3 g·kg−1 of oleic acid, and 0.85 g·kg−1 of water glass.

Potential of low-grade fluorite ore of Landi Kotal, Khyber Pakhtunkhwa Province, Pakistan

“…The plot of grade and recovery versus pH showed that as the pH of pulp was increased from 7 to 10, both grade and recovery were increased but after that a slight decline in grade and recovery was noted. This indicates that around pH 10, the collector-mineral bond is much more stable leading to optimum recovery of 93.02% (Zhao et al 2012;Corpas-Martinez et al 2019). So, for the subsequent flotation trials, the pH of pulp was maintained at 10.…”

Comparison Between Performance of Fluorite Flotation Under Different Depressants Reagents in Two Pieces of Laboratory Equipment

“…A complete description of the cell is carried out in a previous work [30]. Oleic acid was used in all tests as a fluorite collector at a constant dosage of 400 g/t, based on a previous work [31].…”

Testing of New Collectors for Concentration of Fluorite by Flotation in Pneumatic (Modified Hallimond Tube) and Mechanical Cells

“…The order of adding the reagents was as follows: First, once the pH has been reached the value of 9.5, the QT depressant is added to the pulp and conditioned for 5 min [8]. Then the collector is added and let it condition for 2 more min.…”

“…Fluorite is commercialized according to its grade as acid grade fluorite (CaF 2 > 97%) and metallurgical grade (CaF 2 < 97%). To obtain acid grade fluorite it is necessary to use physic-chemical beneficiation methods such as froth flotation [7,8]. Froth flotation is based on surface reactions between minerals and chemical reagents such as collectors and depressant.…”