RU2240363C2 - Method for concentrating zinc-containing waste of process for hot zinc plating of metal - Google Patents

Abstract

FIELD: non-ferrous metallurgy, possibly procession of zinc containing waste in the form of scale.

SUBSTANCE: method comprises steps of charging waste materials into rotating metallic perforated drum having cell size 1 - 3 mm and surface coated with water; rotating said drum until complete separation of smaller fraction. During process of treating zinc-containing waste in rotating perforated drum in water medium it is simultaneously realized abrasive interaction of larger and smaller particles of waste material and separation of disintegrated waste by fractions with particle size less 1 mm and more in range 1 - 3 mm. Loosened particle of zinc scale, mainly being products of interaction of melt of zinc and metal chlorides, possibly due to their structure and small specific density are included in fraction with size less than 1 mm. After process of concentration larger fraction particles contain zinc that has no loosened impurities and is ready for refining and smaller fraction particles contain mixture of metallic zinc with loosened particles of zinc scale. Such waste is used in chemical process for producing zinc salts such as zinc chloride. Such process provides increased by 10 -15 % yield of ready zinc.

EFFECT: simplified effective process for reducing zinc-containing waste, possibility for using in production process received smaller fraction.

3 cl, 1 dwg

Description

The invention relates to the field of non-ferrous metallurgy and can be used for the processing of zinc-containing wastes of the hot galvanizing process.

The well-known "Method for the processing of zinc zinc waste" (RF Patent No. 2147322, C 22 V 7/00, publ. 2000). The method is intended for the processing of zinc waste in the form of an izgar after galvanizing iron and oxidized waste.

According to the known method, the waste is loaded into the melt of an equimolar mixture of sodium and potassium chlorides with the addition of sodium or aluminum fluorides at a temperature of 740-790 ° C, incubated for 15-20 minutes, metal zinc is recovered.

After repeated repetition of this operation, 5-10% of the aluminum of the mass of the melt is added to the melt, an aluminum-zinc alloy is removed, and a precipitate of iron oxides and intermetallic compounds with aluminum and zinc is extracted from the molten salt. Then the operation is repeated.

The known method is complex, multi-stage and expensive due to the reagents used in it, high temperatures, the cost of process safety.

Closest to the claimed technical essence is the "Method of purification of zinc-containing solutions by the deposition of metal impurities" (US Patent No. 3994721, C 22 B 3/00, publ. 1976).

According to a known method, aqueous zinc-containing solutions are subjected to purification from which metal impurities are removed. In the known method, the solution stream is fed into the reactor with a suspension of zinc metal particles in the form of a fluidized bed. Particles of zinc metal larger than or equal to 0.6 mm in size are continuously fed into the lower part of the reactor. Metallic impurities are deposited on artificially introduced particles of metallic zinc.

As a result of multiple collisions of zinc metal particles with each other, metal impurities are erased and removed from them.

The essence of the known method, therefore, lies in the deposition of metal impurities from a zinc-containing solution on particles of zinc metal artificially introduced into the solution.

The zinc-containing wastes of the hot galvanizing process of metal are solid waste - zinc calcare, which is a product of the interaction of zinc melt and salts, for example zinc chloride, ammonium chloride and sodium chloride, formed on the metal during flux treatment before immersion in zinc melt.

In addition, in the process of constant mechanical removal of zinc ogar from the melt mirror, zinc particles from the melt fall into it.

The objective of the present invention is to extract zinc from solid waste production - zinc izgari with the aim of further use of the extracted zinc and the remaining waste.

To solve the problem in the claimed method of enrichment of zinc-containing wastes of the process of hot galvanizing of metal by repeated abrasive action on the particles of the waste in the apparatus with a moving aqueous medium, the waste is loaded into a rotating metal perforated drum, with a mesh size of 1-3 mm, the surface of which is covered with water, which rotate until complete separation of the smaller fraction.

In this case, the enrichment process will be more effective if you use hot water with a temperature of 50-60 ° C.

To prevent “stirring up” - the small fraction of waste being returned to the drum, it is placed in a water bath having a perforated bottom with a mesh size exceeding the mesh size of the drum.

The size of the obtained fractions of waste, provided by the size of the cells, and the temperature of the water are optimal from a technological and economic point of view.

The essence of the claimed method is as follows.

In the process of processing zinc-containing waste in a rotating perforated drum in an aqueous medium, the larger particles with smaller particles are abrasive simultaneously and the crushed waste is divided into fractions with a particle size of less than 1 mm and more than 1-3 mm.

In this case, loose particles of zinc izgar, which are mainly a product of the interaction of zinc melt and metal chloride salts, due to their structure and low specific gravity, appear to be in the fraction with a particle size of less than 1 mm during processing.

Thus, in the enrichment process according to the claimed method in a larger fraction get free from friable impurities, ready for remelting zinc, and in a smaller fraction get particles of a mixture of metallic zinc and loose particles of cinder. This waste material is used in chemical production technologies for zinc salts, for example zinc chloride. At the same time, the ordered size of the calcareous fraction of less than 1 mm is optimal for the synthesis of zinc chloride, because positively affects the dissolution rate of particles.

Thus, a new technical result achieved by the claimed method consists in the abrasive effect of solid zinc-containing wastes of the process of hot galvanizing of metal on each other in an aqueous medium with simultaneous separation of the waste into fractions of a certain composition and size with the possibility of their subsequent use.

The method was tested for the enrichment of 300 kg of zinc-containing wastes of the hot galvanizing process of the Seversky Pipe Plant in the Sverdlovsk Region.

The method is illustrated in the drawing.

Waste (60 kg) was loaded into a perforated drum 1 with holes 2 with a diameter of 1 mm, placed in a bath 3 with hot water at a temperature of 50-60 ° C. Drum 1 with waste was rotated for 30-40 minutes at a speed of m / min.

A waste fraction of less than 1 mm in size through the holes 4 of the perforated bottom 5 enters the bottom of the bath 6 and is sent to obtain zinc chloride. A fraction larger than 1 mm remaining in the drum was sent for the smelting of Zn2 zinc.

Thus, the inventive method allows you to implement a simple economical technology for the recovery of zinc-containing waste, increase the yield of zinc by 10-15% and use the produced fine fraction for production.

Claims (3)

1. The method of enrichment of zinc-containing wastes of the hot galvanizing process of a metal, comprising rubbing particles of zinc-containing wastes moving in an aqueous medium from impurities when separating them into fractions, characterized in that the wastes are loaded into a metal perforated drum with a mesh size of 1-3 mm, the surface of which is coated water, and the enrichment process is carried out by rotating the drum to completely separate the finer fraction. 2. The enrichment method according to claim 1, characterized in that the drum is placed in a bath of water having a perforated bottom with a mesh size exceeding the mesh size of the drum. 3. The enrichment method according to claim 1, characterized in that the enrichment process is carried out at a water temperature of 50-60 ° C.