JP2000107525A - Method for cleaning filter of copper electrolyte filter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with the use of a noxious hydrofluoric acid and thereby enhance the safety of a cleaning operation by cleaning a precoat-type filter which is clogged by a scale or a slime resulting from copper electrolysis, using an ultrasonic wave, when a suspended matter contained in an electrolyte is filtered with the help of a silica precoating agent. SOLUTION: A filter frame with a stainless steel woven metal wire is attached to the internal forward/backward faces of a filter device 3. A silica precoating agent layer is formed on each of the outside faces of the stainless steel woven metal wire using the self-circulation route of the filter device 3 and thus a precoat-type filter 4 is manufactured. When the precoat-type filter 4 which is useless due to clogging is cleaned, no noxious hydrofluoric acid is used. Consequently, a clog-causing matter is shaken to be loosened by suspending a plurality of ultrasonic oscillators 5 instead, in the water between the wall of a water tank and a soaked filter body. Alternatively, the ultrasonic oscillator 5 is attached to the filter device 3 to apply an ultrasonic oscillation to the filter body to loosen the clog-causing matter apart.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper electrolytic solution filtering apparatus for removing suspended matter in an electrolytic solution in an electrolytic refining method for producing electrolytic copper.

[0002]

2. Description of the Related Art An electrolytic solution used in electrolytic refining of copper has a composition of 35 to 50 g / l of copper and 140 to 200 g / l of sulfuric acid.
It is supplied to the electrolytic cell at a rate of about 20-40 l / min / cell. The electrolytic solution that overflowed from the electrolytic cell was sent to a circulation tank after removing suspended matter by a filtration device, where an additive for smoothing the cathode surface was added, and the copper concentration and sulfuric acid concentration were reduced. After being adjusted and then brought to a predetermined liquid temperature by a heat exchanger, it is sent back to the electrolytic cell and circulated. This suspended matter is mainly fine slime, and there are some that have conductivity.If this suspended matter is not returned to the electrolytic cell after being removed by a filtration device, the suspended matter adheres to the cathode surface and becomes a nucleus. Since copper is electrodeposited and grown on the cathode plate around the nucleus, projections are formed on the cathode surface. If the projections grow too large, they will come into contact with the anode to cause a short circuit, which will not only hinder the operation, but also cause the purity of electrolytic copper to be reduced because the projections contain impurities.

[0003] A pre-coated filter is usually used for filtering the circulating electrolyte. This is a filter that uses a diatomaceous earth or other silica-based precoat agent coated on a cloth or a stainless steel wire mesh. When the precoat filter is passed for 10 to 15 days, the flow resistance increases due to clogging of suspended matter trapped in the precoat layer. Therefore, the filtration device is stopped and the precoat layer is regenerated. In this regeneration, the clogged pre-coat layer is washed off by a water shower installed in the filtration device, and then the diatomaceous earth or other silica-based material is again placed on a cloth or a stainless steel wire mesh using the self-circulation path of the filtration device. This is to coat a precoat agent. After coating, the electrolyte solution is passed again and filtered.

[0004] However, after about 6 months of operation, the clogging material consisting of the scale, the precoat material and the fine slime is clogged in the openings of the cloth or the stainless steel wire mesh itself, and cannot be removed. Even though, the liquid flow resistance does not decrease and filtration becomes impossible. The term "scale" as used herein refers to a precipitate of arsenic, antimony, calcium, or the like from an electrolytic solution.

[0005] Therefore, a large and heavy filter which cannot be filtered conventionally is removed from the filtering device to remove the suspended matter and the silica-based precoating agent adhering to the surface of the precoat layer per square centimeter. It is roughly removed with high-pressure water having a pressure of 100 kgf or more (hereinafter referred to as pre-cleaning), and then placed in a hydrofluoric acid cleaning tank filled with hydrofluoric acid which is generally used to dissolve a silica-based precoat agent. The silica-based precoat agent and scale were dissolved and removed by immersion for ~ 50 minutes. The hydrofluoric acid-washed cloth or stainless steel wire mesh body is removed from the hydrofluoric acid cleaning tank, and the hydrofluoric acid is rinsed off in the adjacent water tank.The remaining scale, etc. that could not be dissolved by hydrofluoric acid cleaning was over 100 kgf per square centimeter It was blown off using high-pressure water with water and removed and washed. The cloth or the stainless steel wire mesh body from which the clogging was eliminated was returned to the filtration device again, and the silica-based precoat layer was formed thereon using the self-circulation path of the filtration device, and was repeatedly used as a filter.

[0006] Hydrofluoric acid is also called hydrofluoric acid and is an aqueous solution of hydrogen fluoride. Hydrogen fluoride, along with its aqueous solution, is extremely toxic; it is severely painful when it comes in contact with the skin and penetrates inside and corrodes cells. It is not preferable to use dilute hydrochloric acid instead of hydrofluoric acid, particularly in the case of a stainless steel wire mesh because the stainless steel material is corroded.

[0007]

The hydrofluoric acid that dissolves the silica-based precoat layer is a weak acid, but has high toxicity as described above. The operation of putting a large and heavy filter into and out of the hydrofluoric acid cleaning tank filled with hydrofluoric acid has safety problems such as scattering of hydrofluoric acid.

Further, the cloth or stainless steel wire mesh removed from the washing tank containing hydrofluoric acid partially retains the precoating agent and the scale which could not be completely dissolved, and the hydrofluoric acid was removed in the washing water tank. After washing, these
It was blown off using high-pressure washing water of 100 kgf or more per square centimeter and was washed off.However, when this high-pressure washing water hit a cloth or a stainless steel wire mesh, it bounced off the worker's face or scattered around and was dangerous. there were.

In addition, when performing such a cleaning operation using hydrofluoric acid, for example, when 36 filters are removed from the filtration device, it takes about 4 hours to remove the filters by two persons, and 40 minutes per pre-cleaning. Sheet x 36 = about 24 hours (one person work), cleaning with hydrofluoric acid about 2 hours with two people work, washing with high pressure water for scale removal about the same about 24 hours as the previous wash (one person work), cleaning was completed It takes about 4 hours for two people to install the filter,
A total of about 58 hours (including about 10 hours for two-person work) were spent.

[0010] Therefore, there has been a demand for a method for safely and easily cleaning a pre-coated filter having clogged in a circulating electrolytic solution filtering device for copper electrolysis.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by overflowing and extracting an electrolytic solution from an electrolytic cell.
After the suspended matter in the electrolytic solution is filtered by a filtration device, the filtrate is returned and circulated to an electrolytic tank. In the filter cleaning method of the copper electrolyte filtration device in the electrolytic copper purification method, the filtration device is clogged and passed. Take out the filter in which the liquid became difficult, immerse the filter in the water of the water tank in which the ultrasonic oscillator is installed on the outer circumference or inside, or after immersing in the water of the water tank, put the ultrasonic oscillator on the outer circumference or inside the water tank. After installing, applying ultrasonic vibration to the filter to loosen the adhesion of the clogging of the filter, washing the loosened clogging by blowing it off with high-pressure water, the pre-coated filter is again filtered by the filtration device. A filter cleaning method for a copper electrolyte solution filtration device, wherein the filter is returned to the inside and reused.

Further, in order to further safely and easily clean the clogged pre-coated filter, the clogged pre-coated filter is installed in a filtration device having an ultrasonic oscillator installed on the outer periphery or inside of the filtration device main body. G filter
When washing with the filter attached, ultrasonic vibration is applied during the washing to loosen the fixation of the clogging material of the filter, and the loosened clogging material is washed away by a water shower installed in a filtration device. A filter cleaning method for a copper electrolyte solution filtration device, characterized by performing cleaning.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a method of forming a precoat layer on a stainless steel wire net 1 will be briefly described as an example. As shown in FIG. 2, a predetermined number of filter frames 2 having a total of four stainless steel wire nets 1, for example, 36, are mounted in the filtration device 3 as shown in FIG. A layer of a silica-based precoat agent, for example, diatomaceous earth, is formed on each outer surface of the stainless steel wire mesh using the self-circulation path of the filtration device 3, and the precoat-type filter 4 is completed. The size is about 900mm in length, about 1800mm in width, about 30m in thickness
m. The inside of the stainless steel wire mesh is a passage for the filtrate.

A sulfuric acid electrolytic solution of copper sulfate was passed through the filter precoated with diatomaceous earth to filter the suspended matter.
Regeneration of the precoat layer by stopping the operation of the filtration device every 10 to 15 days due to an increase in liquid flow resistance, that is, the circulating electrolyte was filtered while repeating the recoating of the silica-based precoat layer as described above. Clogging after one month made it difficult to recover the liquid permeation ability even if the precoat layer was regenerated.

The first invention is a method in which toxic hydrofluoric acid is not used for cleaning a precoated filter that has become unusable due to clogging. As an embodiment of the first invention, a clogged stainless steel wire mesh filter taken out of a filtration device is first supplied with 100 kgf per square centimeter.
Using the above high-pressure water, the black suspended matter whose main component is slime, which is attached to the surface of the pre-coat layer made of diatomaceous earth, is blown off, and the diatomaceous earth layer is removed as much as possible. Next, 12 of these filter bodies were lifted with a hanger and completely immersed in water of a 1.7 cubic meter water tank.

Six ultrasonic oscillators were suspended in water between the water tank wall and the immersed filter body, and oscillated for 30 to 60 minutes to loosen the fixation of the clogged material. After the ultrasonic cleaning, the stainless steel wire mesh filter body contains loose clogging scales and hardened pre-coating agent.After removing from the water tank, high pressure water of 100 kgf or more per square centimeter Blow away these loose clogs.

The filter body made of the stainless steel wire mesh which has been washed as described above is returned to the filtration device 3 and coated with a silica-based pre-coating agent by the above-mentioned ordinary method. We were able to.

The second invention uses neither toxic hydrofluoric acid nor high-pressure water, and also has the troublesome removal and installation of the pre-coated filter 4 from the filtration device 3 as in the above-described first invention, and the use of a water tank. This method eliminates the need for cleaning.

As an embodiment of the second invention, an ultrasonic oscillator 5 is attached to the filtering device 3 as shown in FIG. Stop the filtration device every 10 to 15 days due to the increase in liquid flow resistance, remove the clogged pre-coat layer, fill the water into the filtration device, apply ultrasonic vibration to the filter, and perform ultrasonic cleaning every time. Performed for 60 minutes. As a result, the clogging of the stainless steel wire gauze is relaxed before the adhesion of the scale does not grow significantly and the adhesion of the silica-based precoat agent is mild, and the loose clogging is set in the filtration device. It is washed off with a pre-coat layer on the surface by a certain water shower.

According to this method, the washing efficiency is remarkably improved, and the interval at which the passage capacity cannot be recovered even when the precoat layer is regenerated due to clogging of the filter is from 6 months to 1 year.
Extended to months. As a result, the time required to take out the pre-coated filter out of the filtration device and to wash it (about 58 hours per time for 36 filters) and the labor required for it can be reduced.

[0021]

As described above, in the method for cleaning a precoat filter in which suspended matter in an electrolytic solution, which is a sulfuric acid-acidic copper sulfate solution, is filtered using a silica-based precoating agent, the method is based on copper electrolysis. By ultrasonically cleaning the pre-coated filter with clogging caused by scale and slime, the first invention makes it unnecessary to use toxic hydrofluoric acid for cleaning, thus greatly improving the safety of work. Improved.

According to the second aspect of the present invention, in addition to toxic hydrofluoric acid, dangerous high-pressure washing water is not required, and the troublesome removal and installation of the filter from the filtration device and the number of washing operations in the water tank are reduced. did.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a filtration device using a pre-coated filter equipped with an ultrasonic oscillator.

FIG. 2 is a schematic view showing a stainless steel wire mesh before a silica-based precoat layer is formed thereon.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stainless steel wire mesh 2 Filter frame 3 Filtration device 4 Precoat type filter 5 Ultrasonic oscillator 6 Circulating electrolyte inlet pipe 7 Filter filtrate outlet 8 Filtrate pipe 9 Filtrate outlet pipe 10 Lid A Circulating electrolyte before filtration B Circulating electrolyte Filtrate

Claims (2)

[Claims] 1. A copper electrolytic solution in an electrolytic copper refining method in which an electrolytic solution overflows from an electrolytic bath and is withdrawn, a suspended matter in the electrolytic solution is filtered by a filtration device, and the filtrate is returned and circulated to the electrolytic bath. In the filter cleaning method of the filtration device, take out the filter that has become difficult to pass through the clogged filter from the filtration device, immersed the filter in the water of the water tank where an ultrasonic oscillator is installed on the outer periphery or inside, or After immersion in the water in the water tank, an ultrasonic oscillator is installed on the outer periphery or inside of the water tank, and ultrasonic vibration is applied to the filter to loosen the clogging of the filter, and the loosened clogging is performed at a high pressure. A method for cleaning a filter for a copper electrolyte filtration device, comprising washing the pre-coated filter again by blowing it off with water, and then returning the precoated filter to the filtration device for reuse. 2. A copper electrolytic solution in an electrolytic copper refining method in which an electrolytic solution overflows from an electrolytic cell and is withdrawn, a suspended matter in the electrolytic solution is filtered by a filtration device, and the filtrate is returned and circulated to the electrolytic cell. In the method of cleaning a filter of a filtration device, when a clogged pre-coat type filter is mounted on a filtration device having an ultrasonic oscillator installed on the outer periphery or inside of the filtration device main body, an ultra-fine Applying a sonic vibration to loosen the fixation of the clogging material of the filter, and washing the loosened clogging material with a water shower installed in a filtration device to wash the copper electrolyte solution. How to clean the filter of the device.