JPS5847460B2 - Zinc recovery equipment for zinc dust - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for recovering zinc from zinc dust generated in a galvanizing process in a steel mill.

Dust is generated as a by-product during the hot-dip galvanizing process and during the internal blowing process of steel pipes immediately after hot-dip galvanizing, but since this dust contains a large amount of zinc, it can be used in cyclones, bags, filters, etc. The zinc content is captured and reused.

However, in the conventional collection method of forming and collecting dust captured by bags, filters, etc. using a briquette machine or tablet machine, the collection rate is low due to poor formability, and the specific gravity is small, so it is difficult to reuse it. There were many disadvantages such as molten zinc floating on the upper surface and low purity.

On the other hand, there are recovery methods such as a wet method using a sulfuric acid solution and an electrolytic method, which allow relatively high quality zinc to be recovered, but they have the disadvantage of being expensive.

An object of the present invention is to obtain a recovery device with a relatively simple structure that can eliminate the drawbacks of conventional zinc recovery means, and to reduce recovery costs.

The apparatus of the present invention will be specifically explained with reference to the accompanying drawings.

In this device 6, a storage tank 1 for zinc dust, a pressure equalization tank 2, a filling tank 3, and a dissolver 4 are successively installed from top to bottom in order to form a tower-like structure. The arrangement is such that zinc dust is sequentially supplied from the storage tank 1 to the lower tank and molten zinc is discharged from the melter 4.

A loader feeder 5 is installed in the communication path between the storage tank 1 and the pressure equalization tank 2.
is installed, and a swing valve 6 is provided at the tip 6 of the inlet that feeds from the pressure equalization tank 2 to the filling tank 3.

The pressure equalization tank 2 is provided with a pressure introduction pipe 7 for changing the pressure inside the tank.

The filling tank 3 and the dissolver 4 are connected in communication.

The melter 4 is a sealed container made of ceramic or graphite that can withstand the melting temperature of zinc, and is formed into a roughly U-shape. 41 is formed.

Since molten zinc is collected in the melter, a slag discharge port 42 is provided in the upper region, and a cleaning port 43 is provided at the lowest bottom.

Additionally, a water cooling coil 44 is wrapped around the entire outer periphery of the melter 4.

Is the melter 4I by passing high frequency current through the water cooling coil 446? C
It is designed to function as a high frequency crucible induction furnace.

Next, we will explain the 6 functions of this device.

First, the collected zinc dust is charged into the storage tank 1.

Next, the piston valve 81 of the inert gas introduction pipe 8 is opened to maintain the internal pressure of the pressure equalizing tank 2 to atmospheric pressure O with the inert gas, and then the zinc dust in the storage tank 1 is quantified by using the rotary feeder 5c. is supplied into the pressure equalizing tank 2, and then the piston valve 81 is closed, and the piston valve 71 of the pressure introduction pipe 7 is opened to reduce the internal pressure of the pressure equalizing tank 2 from atmospheric pressure using the inert gas 6. Also increase the amount by about 5 to 15 mmAq.

Here, the swing valve 6 is opened to transfer the zinc dust in the pressure equalization tank 2 to the filling tank 3.

The zinc dust fed into the filling tank 3 automatically descends into the melter 4, where it is melted by the high-frequency induction heating of the melter 4, and falls to the bottom of the melter 4, where it remains there.

The zinc dust filling the upper part of the melter 4 is treated with N2, whose pressure is regulated by the pressure regulating valve 72.
An inert gas such as Ar or a reducing gas is introduced at a pressure higher than atmospheric pressure to suppress the oxidation reaction (ignition reaction) during dissolution of the zinc dust.

The apparent volume of the molten zinc in the melter 4 decreases and it falls to the bottom area of the melter 4, but in this device, a certain level of molten zinc remains in the melter in order to increase power efficiency. A zinc discharge port 41 is provided so that the zinc discharge port 41 is discharged, and the zinc flowing out from the zinc discharge port 41 is collected in a galvanizing tank 9 or a zinc ingot case.

The slag discharge port 42 discharges floating impurities in the zinc in a timely manner to prevent the dissolution rate of bent lead from decreasing, and the cleaning port 4
From step 3, precipitated impurities such as iron are discharged in a timely manner.

A cyclone 10 is installed in the pressure introduction pipe and the pressure outlet pipe, and when the piston valve or relief valve is activated, it collects dust adhering to the seal part of the valve and discharges it as appropriate. Rub it 6 times so that it is sent to the storage tank 1 again together with the dust.

By using the device of the present invention, the monthly amount generated per factory can be reduced to 12
Approximately 80% of high-quality zinc can be recovered from 0 tons of zinc dust.

Further, the device itself is relatively simple, the collection cost is low, and it is possible to collect small-sized bag filter dust.

[Brief explanation of drawings]

The drawing is an explanatory diagram schematically showing the overall configuration of the zinc recovery apparatus according to the present invention. 1: storage tank, 2: pressure equalization tank, 3: filling tank, 4: dissolver, 9:
Collection tank.

Claims (1)

[Claims] 1. A storage tank for storing a predetermined amount of collected zinc dust, a pressure equalization tank whose internal pressure can be adjusted and the zinc dust in the storage tank is supplied in a timely manner using a rotary feeder, and a swing valve. A filling tank to which the zinc dust in the pressure equalization tank is supplied in a timely manner, and a substantially U-shaped cylindrical airtight container made of ceramic or graphite connected to the lower part of the filling tank, and located in the upper position. A high-frequency crucible-type induction furnace 6 is constructed by winding a water-cooled coil around which a high-frequency current is applied, which has a slag discharge port, a cleaning port at the bottom end, and a zinc discharge port at the other end.
A method for producing zinc dust, which is equipped with a functionalized container, a zinc discharge port of the melter (a zinc recovery tank located therein, and a piping system for introducing an inert gas or a reducing gas into the melter). Zinc recovery equipment.