Mineral Processing Plant Micaceous Schist Ores Acid Cationic Method for Mica Process

Continuous treatment of the graphitic-mica schist ore included grinding, classification, pre-concentration, conditioning, and flotation. The flowsheet for the process is shown in figure 4.

The ¾-inch dry-crushed ore was stored in an ore bin and withdrawn by a feeder onto a vibrating screen. The minus 4-mesh screen undersize passed to a spiral classifier to remove slimes. The spiral classifier overflowed to a 150-mesh vibrating screen. The minus 150-mesh undersize went to waste. The plus 4-mesh screen oversize, spiral classifier sands, and plus 150-mesh screen oversize passed to a rodmill. The ore was ground in the presence of sodium hydroxide to aid in removing and dispersing slimes. The plus 28-mesh trommel oversize consisted primarily of leaves, trash, and other organic matter and was discarded. The minus 28-mesh trommel undersize passed to a Humphreys spiral to partially concentrate the mica and remove part of the quartz. In addition to rejecting 28 percent of the weight of the ore with a loss of only 5 percent of the total mica, the spiral also rejected most of the pyrite, limonite, and other heavy minerals in the ore. The spiral rougher concentrate passed to a bowl-rake classifier for additional desliming. The bowl-rake classifier overflowed to a 200-

mesh vibrating screen. The minus 200-mesh undersize went to waste. The plus 200-mesh screen oversize and the classifier sands passed to the graphite flotation circuit. A rough graphite product was floated with an alcohol frother, and cleaned once to reject an impure graphite product.

The graphite tailing was dewatered in a spiral classifier. The classifier sands passed directly to the subaeration-type flotation cells, where sulfuric acid for pH control and quartz depression was added. The amine collector (Azamine F10A) was also added in the first flotation cell. A rough mica concentrate was floated in a bank of three rougher cells. The rough concentrate was cleaned twice to produce a finished mica concentrate. The middling product, containing blocky mica, was returned to the rodmill for additional grinding. The flotation process accounted for a recovery of over 83 percent of the total mica in the ore in a product containing 98.7 percent mica. The summarized results of the test are given in tables 10 and 11.