PROCESSING OF GOLD-BEARING INORGANIC MATERIALS INCLUDING PROCESSING OF JEWELLERY SCRAP AND GOLD REFINING Russian patent published in 2014 - IPC C22B9/22 C22B11/00 

FIELD: metallurgy.

SUBSTANCE: proposed method comprises melting of initial stock with flux containing 3-15 wt % of dewatered borax, 0.5-3 wt % of calcium oxide and 0.4-3 wt % of quartz sand relative to the sum of weight of impurities in initial product. Melt heated to 1100-1200°C is bubbled by oxygen-bearing gas to termination of impurities oxidation. Then, oxidised melt is poured at 1200-1250°C into heated lined mould arranged at centrifuge rotor. Mould with melt is spinned at the rate creating the gravity factor Kg=50-500. Note here that used mould allows melt cooling rate not exceeding 10°C/min. Mould spinning is terminated after melt crystallisation termination to obtain casting with temperature lower that solidus temperature.

EFFECT: higher purity and good geometry of final product.

2 cl, 2 tbl