Carrier flotation of ultrafine Egyptian kaolin
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Central Metallurgical Research and Development Institute CMRDI, Cairo
Publication date: 1998-01-01
Physicochem. Probl. Miner. Process. 1998;32(1):265–273
This paper aims to study the amenability of application of the carrier flotation process for removing the anatase impurities, associated with the Egyptian kaolin pre-concentrate (~80 wt. % below 2 μm) to be suitable for paper coating and fine ceramic industry. The tests were carried out using sodium silicate as a depressant and oleic acid as a collector. Limestone was used as a carrier in these tests. The size of the carrier as well as its quantity in the pulp were studied. The results showed that the size of the carrier played a major role in determining the efficiency of the carrier flotation process where a significant improvement in the grade of the concentrate was obtained by decreasing the carrier grain size. The TiO2% decreased to its minimum content (0.6%), in comparison with 1.52% in the feed sample, with its lowest retention ratio when a carrier of grain size –25 +10 μm was used. At such optimum carrier size the degree of whiteness reached its highest value (90) in comparison with 56 for the feed sample. At the same time, the quantity of the carrier in the flotation pulp had no greater influence on the grade of the product. The results showed also that the carrier flotation process can give a concentrate with TiO2% similar to that obtained with the conventional froth flotation technique in presence calcium acetate as an activator, yet the carrier flotation technique has the advantage of reducing the long conditioning time needed for the pulp with the reagents in the conventional technique. The flotation mechanism was discussed.