The Mineralogy Characteristics of Overflow Product from Hydrocyclone in the Jiaojia Gold Mine

The capacity of ore treatment reached 12,000 t/d and gold recovery achieved 92% in the Jiaojia Gold Mine. Broken product has been washed with double spiral classifier, and the ore slime yield was 7%. The ore slime had also been flotation selected alone, which realized preliminary separation between slime and coarse sand. To further improve the gold recovery rate, the practice procedure was modified to subdivide the hydrocyclone in a grinding-flotation system, and the secondary and main slime was pumped into the current slime flotation system. In order to study the nature of overflow products, the experimental instruments were used in the test with Glance Polarizing Microscope, Stereoscopic Microscope, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Infrared Spectrum (IR) and Differential Thermal Analysis (DAT). Research results showed that the mineral species were composed of 4% metal sulfides and 96% gangue minerals. The metal sulfides consisted of about 70.17% pyrite and 16.27% chalcopyrite, whereas the gangue minerals were mainly quartz (about 47.12%) and feldspar (15.90%). The 65% gold was mainly hosted in pyrite and 20% in quartz. The particle size was finer, the content of single particles was higher and the conjuncture particles were less. The grain was finer, the pyrite content was higher and the distribution rate of Au and Ag was higher. The pyrite content reached 73.58% and Au & Ag accounted for 47.99% and 56.60% in -0.037 mm graded particles. The positive correlation was between gold allocation and pyrite content. Gold was not found in coarse grain, microscopic gold accounted for about 30% in medium grain and about 40% of gold in the fine fraction grain. Gold particle size was 2 to 10 microns in the range. Gold shapes were triangle, angular, small granular, irregular shape, etc. Based on infrared spectrum and differential thermal curve, it was found that the finer grain particle had a more complicated composition. Research conclusion provided the regulation for slime flotation from grinding-classification, which has an important practical significance for reagent regulation of slime flotation and determining flotation process.