METHOD AND DEVICE FOR EXTRACTION OF FINE GOLD Russian patent published in 2012 - IPC B03B9/00 

FIELD: process engineering.

SUBSTANCE: invention relates to extraction of minerals by dredging and may be used in placer mining. Proposed method comprises grading initial material to fineness and density, precipitating suspended particles and accumulating them on troughs. Initial material is hydraulically graded to fineness of -2 and +2 mm. Note here that +2 mm-material is directed to processing and extraction of gold while -2 mm-material is subjected to grading to -2 mm- and +2 mm-flows. Flows are accelerated to 0.5-1.0 m/s and gold particles are settled in troughs while rock particles are discharged. Proposed device comprises channel for pulp flow with initial material. It comprises also self-cleaning screen with 2 mm slit to divide the flow into two channels with particle size of +2 mm and -2 mm. Self-cleaning screen with 0.2 mm-slit is arranged in channel for particles of -2 mm, for dividing the flow into channels with 0.2 mm-particles and into channel woth -0.2+2 mm-particles. Said channels incorporate device for grading particles to density and are made up of set of arrow-shaped plates with angle of 60-65° and top edge inclination of 70-75° toward the flow, troughs for gold particles arranged under apparatuses. Note also that plate widths depends upon flow rate and terminal rate of rock and gold particle deposition in compliance with the formula at 0.5 m/s≤U≤1.0 m/s, where L is plate width, m; V_m is pulp flow rate, m/s; g is gravity acceleration, m/s²; 9.8 m/s², k is constant, π=3.14; U_RD rock deposition terminal rate, m/s; U_GD is gold deposition terminal rate, m/s.

EFFECT: higher yield of gold.

2 cl, 4 dwg, 1 tbl