RU2803171C1 - Impact mill - Google Patents

Abstract

FIELD: powder metallurgy.

SUBSTANCE: devices for impact grinding of metal powders. It can be used for processing shavings of refractory metals for reuse in electrometallurgy. The impact mill comprises a housing, a Laval nozzle, configured to supply a carrier gas under a pressure of 1 MPa and shavings made of refractory metal into it through the inlet nozzles, and a fixed baffle-reflector. In the area of the first Mach disk there are cascaded rod fenders made of the same refractory metal. The impact plate is located in the turbulence zone and is equipped with winglets with holes for crushed metal separation.

EFFECT: obtaining a material with a particle shape suitable for uniform movement in the screw conveyor when fed into the melting zone.

1 cl, 2 dwg

Description

The invention relates to the field of manufacturing metal powders by impact grinding and serves, in particular, for processing refractory metal shavings for reuse in electrometallurgy.

An impact mill is known from the prior art, designed for grinding shavings of refractory metals with a minimum content of dust fraction and zero content of wear products for reuse in electrometallurgy [Borisenko D.N., Kolesnikov N.N., Maistrenko S.P., Redkin B. S., Khamidov A.M. Impact mill. // RF Patent No. 2738171 dated 12/09/2020 Bull. No. 34] - prototype. The principle of operation of the prototype is as follows: the energy carrier gas is supplied through the inlet pipe to the Laval nozzle and accelerates the shavings of refractory metal to supersonic speeds; in the area of the first Mach disk there is a fender plate made of the same refractory metal, the chips collide with the fender plate and are destroyed; Thanks to gas-dynamic effects in the region of the first Mach disk, the jet of energy-carrying gas is compressed and, reducing the stagnation region, increases the efficiency and uniformity of impact destruction. To obtain smaller fractions, additional grinding cycles are required, which leads to increased costs for preparing raw materials for remelting. Thanks to the use of “pure impact”, the crushed material is homogeneous in composition, but has a characteristic splintered shape, which makes it difficult to use the crushed material in screw-fed devices, for example, in 3D printers.

The objective of the present invention is to develop an impact mill for crushing shavings of refractory metals and obtaining a material with a particle shape suitable for uniform movement in a screw conveyor when fed into the melting zone.

The technical result is achieved through the use of rod fenders arranged in a cascade in the area of the first Mach disk, and the fender plate is located in the turbulence zone and is equipped with winglets with holes for separating crushed metal. The kinematic diagram of the cascade impact mill is shown in Fig. 1. The numbers indicate: (1) - body; (2) - Laval nozzle; (3) - rod bumpers; (4) - impact plate; (5) - winglets with holes; (6) - supply of energy carrier gas; (7) - chip supply.

The device operates as follows: the energy carrier gas (argon) is supplied to the Laval nozzle (2) under a pressure of 1 MPa through the inlet pipe (6) and at the nozzle exit it acquires a speed of ~400 m/s; refractory metal shavings are fed into the nozzle through the pipe (7); acquiring acceleration and accelerating to supersonic speeds, the chips collide with rod bumpers made of the same refractory metal and cascaded in the area of the first Mach disk; experiencing repeated collisions with the fenders, the chips are destroyed and fall into the turbulence zone, where the fender plate (4) is located; experiencing vortex motion along the surface of the impact plate, the particles are subject to abrasive wear and acquire a more rounded surface topology, suitable for uniform movement in a screw conveyor; reaching the winglets with holes (5), particles of crushed metal are separated and settle to the bottom of the housing (1). The grinding cycle is completed. In fig. Figure 2 shows the chips after a single grinding. With the help of the proposed device, energy costs are significantly reduced and the efficiency of processing secondary raw materials is increased.

Claims (1)

Impact mill for grinding chips made of refractory metal, containing a housing, a Laval nozzle configured to supply carrier gas under a pressure of 1 MPa and chips of refractory metal through the inlet pipes to ensure acceleration of chips to supersonic speed, and a stationary bumper-reflector, characterized in that in the area of the first Mach disk there are cascaded rod fenders made of the same refractory metal, and the fender plate is located in the turbulence zone and is equipped with winglets with holes for separating crushed metal.