CN116065197A - A kind of method utilizing electrolyzer to prepare gold electrolyte - Google Patents

Abstract

The utility model discloses a method for preparing gold electrolyte by utilizing an electrolytic tank. Loading the anode plate and the cathode plate into an electrolytic tank, and adding hydrochloric acid and nitric acid serving as an oxidant into the electrolytic tank; heating and controlling the temperature of the mixed acid solution in the electrolytic tank, starting a rectifier and controlling the electrolytic voltage; and continuously electrolyzing until the end point of the electrolyte preparation is reached. The method omits the procedures of chemical dissolution after coarse gold pulverization and diaphragm electrolysis to prepare gold electrolyte, and then transferring the gold electrolyte to an electrolytic tank for refining, thereby simplifying the procedures and greatly shortening the production period. Meanwhile, the defect that the chemical method is easy to generate toxic and harmful gas to pollute the environment, and the diaphragm cell electrolytic method is easy to generate gold-containing waste such as gold-containing waste diaphragm and the like, and the gold needs to be further treated and recovered is avoided. The utility model simplifies the manufacturing procedure of the gold electrolyte and has the advantages of reducing the manufacturing cost of the electrolyte, reducing gold loss, reducing labor intensity of staff, and the like.

Description

A kind of method utilizing electrolyzer to prepare gold electrolyte

technical field

The invention belongs to the technical field of gold electrolytic refining, and relates to a preparation process method of gold electrolyte.

Background technique

As an important production method of gold refining, the gold electrolytic refining process has been widely used in the production process of crude gold purification. It belongs to the refining method that uses an aqueous solution containing a certain concentration of chloroauric acid and hydrogen chloride as a medium for crude gold purification. The primary process of gold electrolytic refining is to make liquid for gold electrolysis, that is, to make an aqueous solution of chloroauric acid. The traditional preparation method of described chloroauric acid aqueous solution is divided into following two kinds.

One is to pulverize coarse gold into finer particles of gold, or use a flaker to crush gold into thinner gold flakes, then dissolve the gold in a corrosion-resistant container by chemical dissolution, and then filter to obtain a gold-containing solution . The gold-containing solution is transferred to an electrolytic cell as a medium (ie, gold electrolyte) for gold electrorefining.

For example, the Chinese invention patent with the publication number CN110863215A discloses a "method for preparing gold electrolyte from gold electrolysis anode slime". The technical process in this patent involves the production of gold electrolyte, and its raw material is anode slime, a by-product produced during the gold electrolytic refining process. Although the anode slime contains a high grade of gold, it also contains a certain amount of impurities. To prepare the electrolyte, impurities need to be removed first. At the same time, its particle size is finer, which is equivalent to eliminating the pulverization process of chemical dissolution to make the electrolyte. The electrolyte preparation method in this patent is: first dissolve and filter the anode slime with aqua regia, then reduce and remove impurities to obtain gold powder with higher gold purity (fine particle size), and then dissolve it with aqua regia to obtain gold powder with a certain concentration Electrolyte of chloroauric acid, which is then transferred to a gold electrolytic cell for gold electrorefining. It belongs to the category of "pulverizing coarse gold into finer particles of gold, or using a flake machine to crush gold into thinner gold flakes, and then dissolving the gold by chemical dissolution in a corrosion-resistant container, and then filtering to obtain a gold-containing solution." .The transfer of gold-containing solution to an electrolytic cell as a medium (ie, gold electrolyte) for gold electrorefining" category.

For another example, the Chinese invention patent with publication number CN104047024A discloses a "process for preparing high-purity gold by one-time electrolytic refining". The process involves the preparation of the gold electrolyte to take crude gold with a purity of 99% of the gold raw material, pulverize or flake it and add it to a titanium reactor, then add a certain proportion of hydrochloric acid and nitric acid and heat and stir to dissolve the gold. After the reaction is over, it is filtered to obtain Gold electrolyte, which is then transferred to a gold electrolytic cell for gold electrorefining. It belongs to the category of "pulverizing coarse gold into finer particles of gold, or using a flake machine to crush gold into thinner gold flakes, and then dissolving the gold by chemical dissolution in a corrosion-resistant container, and then filtering to obtain a gold-containing solution." .The transfer of gold-containing solution to an electrolytic cell as a medium (ie, gold electrolyte) for gold electrorefining" category.

The other is the diaphragm cell electrolysis method, which is to melt and cast crude gold into an anode plate and then hang it into a diaphragm electrolytic cell containing a certain concentration of hydrochloric acid. This diaphragm allows hydrogen ions and chloride ions to pass through freely and is resistant to high concentration Hydrochloric acid, the method of passing through direct current to carry out electrolytic solution.

For example, the Chinese utility model patent whose publication number is CN212771009U discloses a kind of "gold electrolytic purification automatic refining equipment". This patent involves the production of an aqueous solution of ions (that is, chloroauric acid [AuCl4] ions) and hydrogen chloride (that is, the production of gold electrolyte), which uses a cation exchange membrane to prevent the dissolved chloroauric acid from moving to the cathode for precipitation, which belongs to the traditional diaphragm. One of the electrolytes produced by cell electrolysis.

For another example, the Chinese invention patent whose publication number is CN111304695A discloses "a kind of gold refining equipment and method".

It involves "this solution does not need to configure an electrolyte, and directly hangs the thick gold anode plate on the anode rod of the first tank body". From the perspective of the patent context, it also involves diaphragm electrolysis, which belongs to one of the traditional methods of diaphragm cell electrolysis to produce electrolyte. kind.

The above two methods for making liquid by gold electrolysis have complex and cumbersome procedures, long production cycle, high production cost and large gold loss. Chemical methods are prone to produce toxic and harmful gases, polluting the environment. Diaphragm tank electrolysis is prone to produce gold-containing solid waste such as gold-containing waste diaphragms, which need further treatment to recover gold.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing gold electrolyte using an electrolytic cell, which has simpler liquid-making process, lower liquid-making cost, shorter electrolytic refining cycle, less gold loss, and reduces toxic and harmful gases and Gold-containing scrap diaphragm.

The technical scheme that the present invention adopts is as follows:

A method for preparing gold electrolyte using an electrolytic cell, comprising the following steps: loading an anode plate and a negative plate into an electrolytic cell and adding hydrochloric acid and nitric acid as an oxidant into the electrolytic cell; heating and controlling the temperature of the mixed acid solution in the electrolytic cell, and opening Rectifier and control the electrolysis voltage; continuous electrolysis to the end of the preparation of the electrolyte; wherein, the anode plate is made of coarse gold melting and casting; among them, the judgment condition of the end of the preparation of the electrolyte is: no bubbles are generated on the liquid surface, or the electrode is covered with electrolytic gold by the cathode Board surface.

Preferably, the volume ratio of hydrochloric acid and nitric acid added to the electrolytic cell is: 36-38% analytical pure hydrochloric acid: 65-68% analytical pure nitric acid = (7-9): 1; the mixed acid liquid level is higher than the electrolytic cell circulation overflow The weir is lower than the upper edge of the electrolytic bag.

Preferably, the temperature of the mixed acid solution in the electrolytic cell is controlled at 50-70°C.

Preferably, the electrolysis voltage is a working DC voltage of 2-2.5V.

Preferably, the cathode plate is made of pure titanium.

Preferably, the concentration of gold in the electrolyte is controlled by adjusting the amount of nitric acid added.

Preferably, the cathode plate is a quadrangular plate, and three edges are sealed by insulating materials.

Preferably, the crude gold contains gold with a purity of not less than 98%.

The present invention has the following positive effects:

According to the method of the present invention, coarse gold (that is, the raw material for making gold electrolyte) does not need to be pulverized into finer particles and then chemically dissolved, and there is no need for a diaphragm tank. A mixed solution of hydrochloric acid and nitric acid with a certain concentration, under the double action of voltage and current and the electrochemical dissolution of the dissolving agent, the anode gold accelerates to dissolve and form chloroauric acid into the solution. Dissolved with hydrochloric acid, inhibiting the precipitation of cathode gold. In this way, without using the diaphragm, the anode gold is directly dissolved to generate chloroauric acid ions to stay in the solution and the concentration is continuously increased to form a gold electrolyte. The more prominent advantage of this method of making electrolyte is that the concentration of gold in the electrolyte can be controlled by controlling the amount of nitric acid added. When the added nitric acid is exhausted, the electrolytic refining of gold can be continued directly without transferring the electrolyte, and qualified gold can be produced. product.

The method omits the process of chemically dissolving the coarse gold after pulverization and electrolyzing the diaphragm to form a gold electrolyte, and then transferring the gold electrolyte to an electrolytic cell for refining, thereby simplifying the process and greatly shortening the production cycle. At the same time, it avoids the disadvantages that the chemical method is easy to produce toxic and harmful gases to pollute the environment, and the electrolytic method of the diaphragm tank is easy to generate gold-containing waste diaphragms and other gold-containing solid wastes that require further processing to recover gold. The invention simplifies the production process of the gold electrolyte, and at the same time has the advantages of reducing the production cost of the electrolyte, reducing gold loss (the more processes, the greater the gold loss), and reducing the labor intensity of employees.

Implementation

Below in conjunction with embodiment further illustrate the present invention.

The method of the present invention for preparing gold electrolyte by using an electrolytic cell is used for electrolytic refining and purification of gold, and the process includes steps S1 to S7.

S1: The crude gold melting and casting anode plate is made of 40000g of gold raw material with a gold content of 99.90% purity, which is melted in an intermediate frequency furnace and cast into 20 anode plates, each weighing about 2000g.

S2: Seal the three edges of the cathode plate immersed in the electrolyte with insulating materials. The cathode plate is a pure titanium plate. After heating the three edges of the titanium cathode plate immersed in the electrolyte with a liquefied gas flame, thermoplastic polypropylene powder and Smooth the surface to make it clean and smooth. It is mainly used for edge insulation of the titanium plate to prevent the cathode from depositing electro-gold and wrapping the titanium plate so that it is difficult to remove the electro-gold.

S3: The anode plate and the cathode plate are installed in the tank, wherein the anode plate is hung on the titanium hook of the anode conductive rod, and every ten anode plates is an electrolytic cell (that is, ten anode plates are installed in one electrolytic cell), and then inserted into the polypropylene In the electrolytic bag made of high-quality materials, it is necessary to check in advance whether the electrolytic bag is intact, undamaged, and leak-free before loading into the tank, otherwise, replace it with a new electrolytic bag; the cathode plate is hung on the cathode conductive rod and fastened with screws to maintain good conductivity.

S4: Add 18.7L 30% analytically pure hydrochloric acid and 2.3L 60% analytically pure nitric acid to each small electrolytic cell, making a total of 2 small electrolytic cells, so that the mixed acid liquid level is higher than the electrolytic cell circulation overflow weir and lower than the upper edge of the electrolytic bag.

S5: The heating device is an 800W quartz heating rod, and the temperature control device is a Pt100-lined PTFE temperature-measuring thermocouple to raise the temperature of the mixed acid solution to above 50°C.

S6: Turn on the electrolysis, control the DC working voltage of the rectifier to 2.5V, maintain the electrolytic cell during the period, keep the liquid level of the mixed acid, and add hydrochloric acid after the liquid surface evaporates during the period.

S7: After continuous electrolysis for 7 hours, the circulating acid liquid level in the electrolytic cell returns to calm, no bubbles are generated, and at the same time, a certain amount of electrolytic gold is deposited on the surface of the cathode, and the electrolytic gold deposited on the cathode completely covers the surface of the electrode plate, and the electrolysis of gold has been completed.

Extract the anode gold residue and clean it, dry and weigh about 22.80kg; take out the cathode gold, dry and smelt and weigh about 9.65kg; clean up the anode slime of the electrolytic bag and dry and weigh about 1.22kg; the volume of the electrolyte It is about 42L, and the gold-containing concentration of the electrolyte is calculated to be about 150g/L, which meets the production index production requirements of the gold electrolytic refining electrolyte of the present invention. If the gold content in the electrolytic solution is required to be greater or less than this concentration, the volume ratio of nitric acid can be appropriately increased or decreased.

Claims (8)

1. A method for preparing gold electrolyte by using an electrolytic cell, which is characterized by comprising the following steps: loading the anode plate and the cathode plate into an electrolytic tank, and adding hydrochloric acid and nitric acid serving as an oxidant into the electrolytic tank; heating and controlling the temperature of the mixed acid solution in the electrolytic tank, starting a rectifier and controlling the electrolytic voltage; continuously electrolyzing until the end point of the prepared electrolyte is reached; wherein, the anode plate is formed by casting crude gold; wherein, the judging conditions of the end point of the electrolyte preparation are as follows: no bubbles are generated on the liquid surface, or the cathode is used for precipitating the electro-gold to cover the surface of the electrode plate.

2. The method for preparing gold electrolyte by using an electrolytic cell according to claim 1, wherein the volume ratio of hydrochloric acid and nitric acid added to the electrolytic cell is: 36-38% analytically pure hydrochloric acid: 65-68% analytically pure nitric acid= (7-9): 1; the surface of the mixed acid solution is higher than the circulating overflow weir of the electrolytic tank and lower than the upper edge of the electrolytic bag.

3. The method for preparing gold electrolyte using an electrolytic cell according to claim 1, wherein: the temperature of the mixed acid solution in the electrolytic tank is controlled between 50 and 70 ℃.

4. The method for preparing gold electrolyte using an electrolytic cell according to claim 1, wherein: the electrolysis voltage is 2-2.5V of the working DC voltage.

5. The method for preparing gold electrolyte using an electrolytic cell according to claim 1, wherein: the cathode plate is made of pure titanium.

6. The method for preparing gold electrolyte using an electrolytic cell according to claim 1, wherein: the gold concentration of the electrolyte is controlled by adjusting the adding amount of nitric acid.

7. The method for preparing gold electrolyte using an electrolytic cell according to claim 1, wherein: the cathode plate is a quadrilateral plate, and three edges are sealed by insulating materials.

8. The method for preparing gold electrolyte using an electrolytic cell according to claim 1, wherein: the purity of the crude gold containing gold is not less than 98%.