This work consists of (I) a study of the flotative properties of chalcopyrite in a nearly pure state, and (II) the application of the experimental information to concentrating low-grade chalcopyrite by flotation.
(I) The experiments were performed with a 50-gram flotation machine of M. S. type, made of stainless steel. The pulp consisted of 50 grams of the sample and 200 c. c. of distilled water.
The pH of the tailing solution was determined by means of a potentiometer with a saturated calomel and an antimony electrodes, or a colorimetric comparator.
The ore used was obtained from the Ashio mine, Tochigi, Japan. The sample was crushed and the gangue minerals were rejected by tabling. The table concentrate was further ground after drying, to pass through a 65-mesh. The -65+250-mesh material, containing 29.32% Cu, 29.78% Fe and 3.50% S, was separated from the -250-mesh material by dry screening.
With 360 g/t oleic acid, used, at rate of 90 g/t per 10 min. or 400 g/t sodium oleate, used at rate of 100 g/t per 10 min. it was possible to float off the -65+250--mesh chalcopyrite for 40min. with a 86.3% or a 94.1/ recovery.
The depressors were potassium bichromate, chromium nitrate, citric acid, gum Arabic and tannic acid. Potassium bicllromate was the most effective depressor with 600 g/t or over and citric acid was less sensitive to depression.
Sodium silicate, sodium metaphosphate, copper sulphate, aluminium chloride and iron sulphate had a tendency to slightly depress or activate. Sodium silicate is the most effective activator with 1, 400 to 1, 600 g/t, at pH value of 7.0 to 8.3 after flotation, and gave 82.8 to 94.1% recovery for 10 to 30 min., but reduced the recovery to 70% or lower with 2, 000 g/t or over, at pH value of 8.6. or higher.
(II) The experiments were performed with a 150-gram flotation machine of M.S. type, made of stainless steel. The pulp was 150 grams of the sample and 450 c.c. of tap water.
The ore, containing 2.84% Cu and 64.19% Si02, which was obtained from the Ashio mine, Tochigi, Japan, was crushed and then ground (dry) to pass through a 65-mesh. The pulp was conditioned for 5 min. and the froth collected for 20 min.
Reagents : 210 g/t Nikko-Ranseiyu as frother, and 210 g/t oleic acid. Assay : 19.34/ Cu in the concentrate. Recovery : 90.3% Cu. Selectivity index : 18.0.
Reagents : 1, 500 g/t Na20.4 Si02, 210 g/t Nikko- Ranseiyu, and 210 g/t oleic acid. Assay : 19.46% Cu in the concentrate. Recovery : 93.8% Cu. Selectivity index : 22.9.
Reagents : 1, 500 g/t NaPO3, 210 g/t Nikko-Ranseiyu, and 210 g/t oleic acid. Assay : 21.98% Cu in the concentrate. Recovery : 88.4% Cu. Selectivity index : 16.6.
Reagents : 1, 500 g/t CuSO4, 210 g/t Nikko--Ranseiyu, and 210 g/t oleic acid. Assay : 20.85% Cu in the concentrate. Recovery : 92.4% Cu. Selectivity index : 20.5.
Reagents : 1, 500 g/t AIC13, 210 g/t Nikko--Ranseiyu, and 210 g/t oleic acid. Assay : 17.78% Cu in the concentrate. Recovery : 88.0% Cu. Selectivity index : 14.2.
Reagents : 1, 500 g/t Fe2 (S04) 3, 210 g/t Nikko-Ranseiyu, and 210 g/t, oleic acid. Assay : 18.54% Cu in the concentrate. Recovery: 93.6% Cu. Selectivity index : 18.3.
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