Analysis of processing flowsheets of refractory gold ore from the Aktobe deposit, cyanidation of initial ore and concentrates

The article presents the results of enrichment of gold-bearing ore from the Aktobe deposit, containing 1.57 g/t of gold, using flotation and gravity–flotation flowsheets with a closed flotation circuit. The expediency of obtaining gold-bearing concentrate by flotation with one cleaner operation is established. The following process indicators are obtained: the yield of the flotation concentrate is 6.13%; the gold content is 23.01 g/t at the recovery of 89.84%. The comparative analysis of the closed-loop flotation circuit results shows that the obtained indicators in both flotation and gravity–flotation flowsheets are approximately at the same level. The highest process indicators in terms of recovery are obtained using the integrated grinding–centrifugal concentration–flotation flowsheet with one cleaner operation. In this case, gold recovery is 90.56%, which is 0.72% higher than the recovery in flotation flowsheet. The studies on gold cyanidation and adsorption at activated carbon grade Gold Curb 207 C demonstrate low gold recovery, both during cyanidation of the original ore (recovery 62.42%) and during cyanidation of the flotation concentrate (recovery 48.53%). To increase the cyanidation efficiency, the methods of concentrate preparation for cyanidation such as pyrometallurgical treatment (roasting) and mechanical activation (ultrafine grinding) are recommended. The study was supported the Committee of Science of the Ministry of Science and Higher Education of the Republic of Kazakhstan, Grant No. АР19680182.