PROCESS FOR PREPARING COPPER POWDER

The invention relates to a process for preparing copper powders by atomizing molten metal with high-pressure water and to a copper powder which is used as a starting material for producing filters, sleeves, toothed wheels, bearings, sparking plugs, Cu-graphite composite materials or brake pads for motor vehicles, by sintering or sinter-moulding. The claimed process has the following stages : smelting a charge of copper wastes in an induction furnace, pouring the molten mass with a temperature of 1300°C in a pouring gate provided at its lower part with a nozzle with the diameter of 10 mm having the role of forming a vein of molten metal with the same diameter which flows in the atomizing tower wherein it is disintegrated by the high-pressure water jets of a multi-jet type atomizing system with 12 nozzles, circularly arranged, so that the axis of water jets forms angles of 11° with the vertical of the molten mass axis of flow, the water jet having a diameter of 1 mm and a pressure of 9 MPa, with a flow rate of the atomized water of Q= 0.1 m/min ensured by Woma-type pump, followed by drying the metal particles in an electric furnace at a temperature of 200°C and by granulometric sifting with the retention of particles < 425 μ m, followed by the thermochemical treatment of reduction in dissociated NHat a temperature T= 550°C and grinding the resulting copper sponge in a Chilean mill at a speed of 12 rpm. The claimed Cu powder has the following composition: 0.013...0.01% Si, 0.096...0.12% Fe, 0.025...0.06% Ni, 0.06...0.9% Sn, 0.023...0.3% Zn, 0.043...0.06% Pb, 0.24...0.25% O, 98.3...99.5% Cu, the grain shape is irregular, the granulometric fraction < 212 μ m =70%, the flow rate V=36s/100 g and the apparent density ρ= 4.15 g/cm. Invenţia se referă la un procedeu de obţinere a pulberilor de cupru, prin pulverizarea metalului topit cu apă sub presiune, şi la o pulbere de cupru care este utilizată ca materie primă pentru realizarea, prin sinterizare sau prin sintermatriţare, a filtrelor, bucşelor, roţilor dinţate, lagărelor, bujiilor, materialelor compozite Cu - Grafit sau a plăcuţelor de frână pentru autoturisme. Procedeul conform invenţiei are următoarele etape: elaborarea, într-un cuptor cu inducţie, a unei şarje formate din deşeuri de cupru, turnarea topiturii cu temperatura de 1300°C într-o pâlnie de turnare prevăzută, la partea inferioară, cu o duză cu diametrul de 10 mm, ce are rolul să formeze o vână de metal topit cu acelaşi diametru, care curge în turnul