WO2008144967A1

WO2008144967A1 - A method for recovery and production of ultrafine zinc powder

Info

Publication number: WO2008144967A1
Application number: PCT/CN2007/002230
Authority: WO
Inventors: Yang Yu; Yongli Li; Guilong Li
Original assignee: Yu, Jun
Priority date: 2007-05-29
Filing date: 2007-07-23
Publication date: 2008-12-04
Also published as: CN100586617C; CN101314184A

Abstract

A method for recovery and production of ultrafine zinc powder from zinc-containing dust involves steps as follows: adding zinc-containing dust into alkaline solution, stirring the solution at the temperature 20?~60? and separating the solid and the liquid after zinc is leached into the solution; primary electrolyzing the obtained solution at the condition of a lower voltage and a lower current density to reduce the metals whose electro-positivity is higher than that of zinc and recovering the reduced metals; increasing the voltage and the current density to electrolyze intensively the solution obtained after the primary electrolysis so as to zinc powder being deposited on the cathode, and recycling the alkaline solution to the leaching stage; treating the obtained zinc powder with highly volatile liquid to dehydrolyze and dry it so as to obtaining pure and dry ultrafine zinc powder with different particle diameters, and recycling the highly volatile liquid; intensively leaching the metals that have not been leached by alkali and recovering them as raw material in smelting, while recycling the leach solution that contains lower content of zinc to the leaching stage.

Description

Method for recovering and preparing ultrafine zinc powder from zinc-containing powder

The invention relates to a preparation method of ultrafine zinc powder, in particular to a method for preparing ultrafine zinc powder by using zinc powder containing blast furnace dust or the like.

Background technique

Ironmaking blast furnace soot is an intermediate product with low zinc content but harmful to iron making. Because it is returned to the blast furnace, it is easy to generate a furnace to cause harm to the production, and it is not only polluting the environment but also wasting resources. A variety of recycling methods have emerged for a long time. The main two categories (1) are small proportions of iron ore to recover iron, and zinc slag is discarded. (2) Roasting and volatilizing The dust is reduced at 1600 °C in a rotary kiln, and zinc is oxidized and recovered from the gas phase, and the iron slag is discarded. The above method recovers only one metal and the product is still the raw material.

Zinc-containing powders such as cobalt slag and molten slag in the wet zinc smelting process, zinc powder in the vertical tank zinc smelting process, blue powder, zinc powder which is not condensed into liquid zinc during electrothermal smelting, etc. , are running between 10% and 90%. Currently used to produce zinc sulphate, zinc chloride or return to the zinc smelting process to produce zinc ingots.

Patent Application Publication No. CN1817518A discloses a method for producing metal zinc powder by using zinc dust or zinc dross, leaching zinc-containing powder with a strong alkali solution, filtering and precipitating lead with sodium sulfide, etc., and then electrolytically depositing Zinc powder has many operating steps. The separation of lead in zinc-containing powder can only be used as a raw material for lead smelting and cannot be directly used as a product.

Zinc powder is an important raw material in the metallurgy and paint industry. There are two main methods for preparing zinc powder. (1) One is to atomize the metal zinc liquid and rapidly cool it. (2) Adding metal zinc liquid Hot gas, rapid cooling. The zinc powder produced by the above method is difficult to produce a particle size of less than 47 μm, and the raw material must be metal zinc. Summary of the invention

SUMMARY OF THE INVENTION The object of the present invention is to overcome the deficiencies of the prior art and to provide a method for preparing ultrafine zinc powder from a zinc-containing powder such as blast furnace dust or the like which is simple in process, convenient in operation and low in cost.

The technical solution to achieve the above objectives is:

A method for recovering and preparing ultrafine zinc powder from a zinc-containing powder material, comprising the following steps:

(1) adding the zinc-containing powder to the alkali solution, immersing the zinc into the solution under stirring at a temperature of 20 ° C to 60 ° C, and separating the solid and liquid;

(2) a solution obtained by primary electrolysis under conditions of low voltage and low current density, wherein the impurity metal in the solution which is more positive than zinc is reduced and recovered;

(3) increasing the voltage and current density, electrolyzing the solution after primary electrolysis, depositing zinc powder on the cathode, and circulating the alkali solution as a leaching material;

(4) The zinc powder is dehydrated and then dried with a volatile liquid to obtain ultra-fine zinc powder of different particle size grades, and the volatile liquid is recycled and recycled;

(5) Deeply leaching a slag such as a metal which is not leached by alkali, recovering the metal as a smelting raw material, and simultaneously obtaining a leaching liquid having a lower zinc content for recycling as a leaching raw material.

In a preferred embodiment, a strong alkali solution having a concentration of 50 g/L or more is used as a raw material for leaching.

In a preferred embodiment, a sodium hydroxide solution having a concentration greater than or equal to 50 g/L is used as the leaching material. In a preferred embodiment, ammonia water having a concentration greater than or equal to 10% or more is used as the leaching material. '

In a preferred embodiment, the solid-liquid separation is carried out by adding a flocculant to the mixed liquid after leaching and then filtering.

In a more preferred embodiment, the flocculating agent is a polyacrylamide flocculant or an inorganic flocculant.

In a preferred embodiment, the primary electrolysis voltage is 2 to 3 V and the current density is 10 to 100 A/m ² .

In a preferred embodiment, the deep electrolytic voltage is 3 to 5 V, and the current density is 200 to 1800 A/m ² .

The method of the invention not only avoids the environmental pollution problem caused by the waste of zinc-containing dust or slag, but also fully recycles and utilizes the obtained zinc powder with a particle size of not more than 47 micrometers, which is a high-quality raw material for the paint industry and the like; The process conditions are easy to control, and the material input of the whole process becomes the target product or industrial raw material. There is no waste discharge, and it will not cause environmental pollution. DRAWINGS

Figure 1 is a flow chart of the invention for recovering and preparing ultrafine zinc powder from a zinc-containing powder.

detailed description

The invention is illustrated by the following examples, but the examples do not constitute any limitation of the invention. Example 1

The zinc-containing powder is 100 kg of blast furnace soot. The main component is: zinc 16.1% (mass percent, the same below), lead 1.13%, manganese 1.21%. The powder was subjected to wet ball milling, sieved through 60 mesh, and settled to obtain 130 kg of slag, and the water was recycled. Join 800 liters of 480 g / liter of aqueous sodium hydroxide solution, after stirring for 30 minutes, 6 grams of polyacrylamide flocculant was added, and after sedimentation, 800 liters of the supernatant was obtained. The supernatant is filtered, and the filter residue is used as a smelting raw material to recover metal. The obtained electrolyte is 1. 98 volts, and the positive electrical impurity metal such as lead is removed at a temperature of 2.2 volts at 20 amps/m 2 . After removing the impurities on the cathode plate, the voltage was increased to 3.2 volts to control the current density of 500 amps/m2, and after electrolysis for 2 hours, 17.40 kg of wet zinc powder was scraped off. It was washed with a volatile solvent such as absolute ethanol and dried to obtain 15.11 kg of dry zinc powder, which all passed through a 325 mesh sieve. The zinc content is 99.35%, and the metal zinc content is 98.33%, which meets the standard of the first metal zinc powder. The lye after electrolysis is used for deep leaching to separate the supernatant from the supernatant, and the leached mixture separates the supernatant as a leaching material for recycling, and the underflow is pressure-filtered, and the filtrate is used as a leaching material and filter residue. The metal is recovered as a raw material for smelting.

Example 2

The zinc-containing powder is 100 kg of blast furnace soot. The main component is: zinc 12.1% (mass percentage, the same below), lead 1. 75%, manganese 1.93%. A 20% (mass%) aqueous ammonia was used as the leaching material. The procedure is similar to that of Embodiment 1. In the primary electrolysis process, the voltage is 3V, the current density is lOOA/m ² , and the positive electrical impurity metal such as lead is 2.27 kg. The deep electrolysis voltage was 5 V, the current density was 1800 A/m ² , and the dry zinc powder was 11.08 kg. The zinc powder was all passed through a 325 mesh sieve. The total zinc content is 99.22%, and the metal zinc content is 97.96%, reaching the primary metal zinc powder standard.

The invention has been described above by way of examples, but the examples are not intended to limit the invention. Any changes or modifications within the scope of the claims of the invention are within the scope of the invention.

Claims

Claim

1. A method for recovering and preparing ultrafine zinc powder from a zinc-containing powder, comprising the following steps -

(1) adding the zinc-containing powder to the alkali solution, immersing the zinc into the solution at 20 ° C~6 (TC temperature stirring, solid-liquid separation;

(2) The solution obtained by primary electrolysis under low voltage and low current density conditions, the impurity metal in the solution being more positively charged than zinc is reduced and recovered;

(4) The zinc powder is dehydrated and then dried with a volatile liquid to obtain pure and dry ultra-fine zinc powder of different particle size grades, and the volatile liquid is recycled and recycled;

(5) Deeply leaching a slag of metal such as metal which is not leached by alkali, recovering the metal as a raw material for smelting, and simultaneously obtaining a leaching liquid having a lower zinc content for recycling as a raw material for leaching.

The method for recovering and preparing ultrafine zinc powder from a zinc-containing powder according to claim 1, wherein a strong alkali solution having a concentration of 50 g/L or more is used as a raw material for leaching.

The method for recovering and preparing ultrafine zinc powder from a zinc-containing powder according to claim 2, wherein a sodium hydroxide solution having a concentration of 50 g/L or more is used as an leaching material.

The method for recovering and preparing ultrafine zinc powder from a zinc-containing powder according to claim 1, characterized in that ammonia water having a concentration of greater than or equal to 10% or more is used as a raw material for leaching.

5. The method for recovering and preparing ultrafine zinc powder from a zinc-containing powder according to claim 1, wherein the solid-liquid separation is carried out by adding a flocculant to the mixed liquid after leaching and then filtering.

The method for recovering and preparing ultrafine zinc powder from a zinc-containing powder according to claim 2, wherein the flocculating agent is a polyacrylamide flocculant or an inorganic flocculant.

The method for recovering and preparing ultrafine zinc powder from a zinc-containing powder according to claim 1, wherein the primary electrolytic voltage is 2 to 3 V and the current density is 10 to 100 A/m ² .

The method for recovering and preparing ultrafine zinc powder from a zinc-containing powder according to claim 1, wherein the deep electrolytic voltage is 3 to 5 V and the current density is 200 to 1800 A/m ² .