Applying One-Stage Grinding and Flotation to Improving Copper Recovery of a Fine-Grained Cu-Mo Sulphide Ore

Abstract

This paper introduces the mineralogy of a fine-grained Cu-Mo sulphide ore, and the relationship between grinding fineness and flotation performance. Results show that the grinding fineness is a key factor affecting the recovery of copper and molybdenum. The result of one stage grinding and flotation is much better than that of grinding and flotation by stages, because an over grinding of chalcopyrite caused by regrinding of Cu-Mo bulk concentrate can be avoided. Finally, a simple flowsheet has been developed, that is, one-stage fine grinding of raw ore to 90% À0.074 mm, and a bulk flotation to produce a bulk concentrate by one-stage roughing, two stages of cleaning and one-stage scavenging, followed by three times of Cu-Mo flotation separation. When the feed contains 0.50% Cu and 0.19% Mo, the obtained copper and molybdenum concentrates assay 19.23% Cu and 48.53% Mo with the recoveries of 85.5% and 90.96%, respectively. INTRODUCTIONPorphyry copper deposits are the world's main source of copper and molybdenum. The recovery of molybdenum from porphyry copper ores by flotation is easily affected by particle morphology, inherent hydrophobicity and possible formation of slime coatings on it (1). It is essential to investigate all the factors before the molybdenum recovery process, and besides researching the particle morphology, researching the grinding fineness which affect particle size directly is a key to obtaining better flotation results.Generally, molybdenum in the form of molybdentie (MoS 2 ) and copper in the form of chalcopyrite (CuFeS 2 ) are recovered by two stages of grinding and separation. First, primary grinding is followed by a bulk flotation to enrich copper and molybdenum minerals in a bulk concentrate, and then the bulk concentrate is reground and separated by flotation (2-3). But an interesting phenomenon is that molybdenite recovery in the bulk flotation circuit is consistently lower than that of the copper sulphides as well as being far more variable (4) though molybdenite shows an excellent hydrophobicity. With the exception of the usual reasons like ore mineralogy, flotation reagents, and flowsheet which affect flotation indicators, the main reason leading to this phenomenon is grinding fineness as well as method.In the copper and molybdenite separation circuit, the molybdenite can usually be recovered first by depressing the copper and iron sulfide minerals with reagents like lignosulfonates under the high pH conditions (5), sodium sulfide, sodium silicate used as slime depressants, and pH modifier (6). Xanthate are the most common collectors for collecting sulfide minerals, but kerosene, nonpolar oil, emulsified oil, and other hydrocarbons can replace it to float the molybdenite or copper-molybdenite sulfide minerals (7-8). Researchers pay much attention to copper and molybdenite flotation reagents because fit reagents utilization and dosage is beneficial for copper and molybdenite recovery and it is not easy to recover them.It has been more than ten years since the Jiudingshan Cu-Mo mine (D...