BG66180B1 - Method and installation for selective extraction of metal cations from weak acid to weak basic solutions - Google Patents

Abstract

The method and the installation find application in the treatment of solutions and other industrial flows without any preliminary preparation. The method for selective extraction of metal cations from solutions comprises operations in the following succession: The metal-containing solutions are subjected to enrichment in ionexchanging columns connected in series. After that regeneration follows by feeding regeneration solutions, and washing by feeding the solutions in the feed direction of the regeneration solutions. The installation comprises ionexchange cells representing two in-series connected single-chamber columns made up of upper and lower plates with in-series connected nozzles arranged thereon for distribution of the solutions.

Description

The invention relates to a method and installation for the selective extraction of metal cations from weak acids to weakly basic solutions, suitable for use in the treatment of solutions obtained from leaching of copper heaps and piles, acid mine drainage, as well as for the extraction of metal cations from other industrial flows.

BACKGROUND OF THE INVENTION

There are various technological methods for extracting metal from metal-containing ores. For many of them, for various reasons, including the imperfection of technology, it is not possible to fully extract the contained metal, which is why around the processing plants there are accumulated large heaps and heaps, which represent the storage of residual products and large volumes. metal-containing solutions. In most cases, because of the relatively high content of metal in these solutions, it is economically advantageous to treat them in order to recover the metal contained therein. Equally important is the fact that the extraction of metals from these solutions is mandatory from an environmental point of view.

Various installations are known for the processing of metal-containing solutions for the purpose of extracting the metal contained therein, using the ion-exchange process in facilities known as ion-exchange columns. In order to achieve high efficiency in the recovery of metal cations, the columns are designed to absorb and maintain the ion exchange resin in a certain state, while ensuring a uniform distribution of feed, regeneration and washing solutions passing through the resin layer. Two modes are known and used in practice: in a sealed layer in which the ion exchange resin is not removed from the column and another mode characterized by the removal and transfer of the ion exchange resin to another column.

A method and installation for ion exchange treatment of solutions in two columns (GB 203964) is known, characterized in that after the resin in the first ion exchange column is loaded with the corresponding cation, it (resin) is transferred to the second column to regenerates, after being regenerated in the second column it is again transferred to the first column for its loading, keeping the resin closed and operating cyclically. Before transferring the resin from one column to the next, it is separated from the feed solution by washing with water or by displacing it with the solution to be fed into the column where it is moved. Between the two columns corresponding to the two stages of the process, the ion exchange resin and the product solutions (salts and acids) involved in the process alternatively circulate counter-cyclically, shifting in each semi-cycle the ion exchange zone from one end of the column to the other end and treatment technology. of metal-containing solutions - WO 9632999, which consists of the following operations: enrichment of the resin in ion-exchange columns, followed by purification, which results in the supply of a dilute low-acid stream consisting of electro um and sulfur dioxide in enriched volume gum, which achieves the removal of sorbed from the resin iron. The resin is then subjected to complete iron purification, since almost 10% of the total amount of adsorbed iron remains almost always after the previous purification step. After complete purification, regeneration is carried out using a solution representing an acid solution containing 25-30 g / Ι, and two volumes of regeneration solutions per volume of resin are required for regeneration on each column. Finally, a flush is carried out which removes the residues from the regeneration solutions. The technological process described above is carried out in an installation consisting of 30 identical ion-exchange columns arranged on a rotating disk, all columns being filled with resin. Installation

66180 Bl consists of a movable and immovable part, the movable part being formed as a rotating head and made of corrosion-resistant metal, and the movable head is made of non-metal, for example a polymer, and the seal between the two (movable and immovable) parts is supported by a pneumatic force that presses them together. The installation permits simultaneous rotation of the 30 columns and their attachment to the inlet and outlet of the solutions in a synchronized sequence.

Thus, the 30 columns can work in many different ways depending on the desire of the operator. The columns can be connected in series or in parallel, operate with upstream or downstream solutions, etc.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method and installation for the selective extraction of metal cations from weakly acidic to weakly basic solutions, which will provide efficient extraction of metal cations by treating solutions obtained from leaching of heaps, piles, mine drainage, and industrial flows without preliminary preparation of the solutions.

The method for selectively recovering metal cations from solutions involves performing operations in the following sequence: the metal-containing solutions are subjected to enrichment in series-linked ion exchange columns containing an ion exchange resin, the columns are connected to each other, and the solutions are passed through the resin layer and then passed through the resin layer. performs regeneration by feeding regeneration solutions and washing, which is carried out by feeding the resin in the direction in which the regeneration solutions are fed.

According to the invention, prior to supplying the feed solutions to the ion exchange columns, the solutions are subjected to a pH adjustment corresponding to the resin optimum value, which prevents the formation of hydroxides while providing the necessary metal sorption and enrichment the feed solutions being fed from the top of the first column to the bottom, from which they pass to the bottom of the second column and exit through the top, at which point the regeneration begins at the moment when the content of the m The content in the stock solutions is equal to the copper content of the feed solutions as well as the extracted metal in the solutions after the first column and the trace of it in the solutions after the second column. The breakthrough of the recovered metal in the solution after the first column indicates that the resin in it is already rich and needs regeneration. At this point, the first column is disconnected from the enrichment process and begins to regenerate. The second column continues to operate in the enrichment mode, changing the direction of the feed solutions, i.e. they enter through its upper part, pass through the rich resin layer and exit through its lower part. After the first column has already been regenerated, the same column is flushed and restarted, both columns having already changed positions and directions with respect to the supply of solutions, namely the feed solutions entering through the top of the second column, passing through, leaving from its lower part, enter through the lower part of the first column and exit through its top (Fig. 4). Once the resin in the second column is already enriched, the resin is disconnected from the enrichment regime and begins to regenerate. The first column continues to operate in the enrichment mode, with feed solutions fed through its upper part, passed through the rich resin layer and exited through its lower part, and the washing solutions recycled back into the system and used to prepare regeneration solutions for the next cycle.

The task is also solved by the metal cation extraction plant, which consists of ion exchange columns connected in series.

According to the invention, the installation consists of at least one ion exchange cell made up of two, in series, connected single-chamber columns, filled with upper and lower plates. The plates are connected to the supply and connecting pipelines with the control valves of a certain type located on them - valves, valves, nozzles for distribution of solutions (not shown in the figures).

The method and installation for treating the solutions according to the invention make it possible to obtain a final product of extremely high quality. The method allows for the treatment of solutions without the need for pre-treatment. The technology allows for optimization of the ion exchange process while preventing mechanical damage to the resin. Conducting the ion exchange process is as simple as possible, since there is no need for additional (fast) flushing procedures, which in known technologies are used to inflate the ion exchange resin layer and improve flow characteristics. It is appropriate to note that the described flow direction organization allows ion exchange and regeneration processes to be carried out with minimum pressure losses, respectively - at lower mechanical stress and consequently slower "wear" of the resin. The formation of "channels" in the resin layer is further minimized.

In the mode of enrichment in the lower or upper part of the column (depending on the direction of flow of the solutions), the resin works in the absence of copper, resulting in the sorption of other ions. A change in the direction of solution delivery eliminates this problem and the resin is enriched mainly with copper ions. This also determines the extremely high selectivity of the extraction process. The system is "self-cleaning", ie. a change in the direction of flow of the solutions results in a regular cleaning of the filters located at the top and bottom of the column, which in turn ensures uniform flow rates. The invention features a simplified installation design, easy operation, the ability to fully automate all technological processes.

Explanation of the annexed figures

The following is an exemplary embodiment of the method and installation of the invention, illustrated with the help of the accompanying figures:

Figure 1 is a general view of an ion exchange cell installation;

Figure 2 is a sequence of enrichment of the solution in a first ion exchange column according to the method;

Figure 3 is a step of completing enrichment in a first ion exchange column and starting enrichment in a second ion exchange column and regeneration in a first ion exchange column;

FIG. 4 is a process of enriching the solution in a second ion exchange column and reversing the flow of motion when regeneration begins in a second ion exchange column; FIG.

Figure 5 - complete cycle of enrichment of the solutions in the two columns, with the removal of the washing solutions and their preparation for regeneration solutions in the next cycle of enrichment.

Examples of carrying out the invention

In the following, an exemplary embodiment of the method and installation for treating metal-containing solutions will be presented, which does not limit its application to other solutions characterized by the same or similar parameters and characteristics. The ion exchange process is a reversible chemical reaction in which an ion from a solution is replaced by an "attached" ion to a solid particle with the same charge. Solid ion exchange particles are either naturally occurring inorganic zeolites or synthetic organic ion exchange resins. Currently, synthetic organic resins are often used as they can be designed to be used for a specific purpose.

Organic ion exchange resin is usually a high molecular weight polyelectrolyte that has the ability to replace its mobile ions with those with the same charge from the surrounding environment.

An exemplary embodiment of the method according to the invention relates to the treatment of solutions obtained by leaching of copper sole. The method begins with the preliminary preparation of the feed solutions, the copper content of which ranges from 0.02 to 6 g / l and in the filtrate 0.001 g / Ι. The method is characterized by the preliminary preparation of the solutions, which is expressed in the correction of the pH values of the solutions, preferably the pH indicator in the rich leaching solutions is in the range of 1.5-4.0. It has been found that these values do not reach 50

66180 B1 initiates the formation of hydroxides and at the same time creates suitable conditions for the effective sorption of the metal contained in the solutions.

Enrichment of metal-containing solutions is carried out by feeding the feed solutions in the direction from the top of the first ion exchange column to its bottom, from where they pass to the bottom of the second ion exchange column and exit through its upper end, at which point the regeneration begins at the moment when the copper content in the stock solutions equals the copper content of the feed solutions as well as the metal recovered in the solutions after the first ion exchange column and the presence of traces of metal in the solutions after the second column. The presence of the recovered metal in the solution after the first column indicates that the resin in it is already rich and needs to be regenerated. The regeneration of each column with a sulfuric acid solution with a concentration of up to 200 g / Ι produces a regenerate containing 15-18 g / 1 copper. At this point, the first ion exchange column disconnects from the enrichment process and begins to regenerate. The second column continues to operate in the enrichment mode, changing the direction of the feed solutions, ie. they enter through its upper part, pass through the rich resin layer and exit through its lower part. After the first column has already been regenerated, the same column is flushed and restarted, both columns having already changed positions and directions with respect to the supply of solutions, namely - feed solutions enter through the top of the second column, pass through it , emerge from its lower part, enter through the lower part of the first column and exit through its top (Fig. 4). Once the resin in the second column is already enriched, the resin is disconnected from the enrichment regime and begins to regenerate. The first column continues to operate in the enrichment mode, with feed solutions fed through the upper portion, passed through the rich resin layer and exited through the lower portion, and the washing solutions recycled back into the system and used to prepare regeneration solutions for the next cycle. The described cycle of enrichment of metal-containing solutions is carried out in ion-exchange cells, made up of two, successively connected ion-exchange columns, respectively 1 and 2, each filled with upper 3 and lower 4 plates, to which conduits for supplying feed and regeneration solutions are connected. The control elements, which are standard and well-known valves, valves, check valves and nozzles not shown in the figures, are attached to the pipelines. Using the described sorption installation made up of one or more ion-exchange cells connected in succession, an effective enrichment of the resin with copper ions is carried out, thereby achieving efficient extraction of the copper ions from the metal-containing solutions.

The resulting regenerate is further subjected to subsequent extraction, preferably liquid extraction and electrolysis, to obtain high quality copper cathodes. The end product is copper cathodes of exceptional quality and purity of 99.999%. The extraction and electrolysis processes are applied at known and standard parameters and are therefore not of interest and protection to the present invention.

Claims (3)

1. A method for selectively recovering metal cations from solutions, comprising feeding metal-containing enrichment solutions into sequentially coupled ion-exchange columns containing an ion exchange resin, the solutions passing through a resin layer, after which regeneration is effected by feeding regenerative solutions in the direction of the direction of the metal-containing solutions, and subsequent washing, characterized in that, prior to the supply of the metal-containing solutions in the ion-exchange columns, they are carried out pH reduction in the range of 1.5 - 4.0, and the enrichment is carried out by feeding the feed metal solutions through the top of the first column and aiming at the bottom, from where they pass to the bottom of the second column and exit through the top, whereby, in the conditions of even copper content in the stock solutions and in the feed solutions, the recovered metal is regenerated in the solutions after the first column and traced therein in the solutions after the second column, 66180 Bl, where, in the presence of the recovered metal in the solution, regeneration is carried out in the solution after the first column, and the ion exchange resin is enriched in the second column, the direction of the feed solutions being changed, whereby after completion of the regeneration in the first column, washing is carried out and reintroduced into the process, both columns having already changed positions and directions with respect to the feeding of the solutions, namely the feed solutions entering through the top of the second column, passing through, exiting its part, enter through the lower part of the first column and exit through the top and, since the resin in the second column is already enriched, it is excluded from the enrichment mode and begins to regenerate, whereby the first column continues to operate in the enrichment mode , as feed solutions enter the top, pass through the resin layer, and exit through the bottom, and the wash solutions are recycled back into the system and fed to prepare regeneration solutions for the next cycle. 2. A plant for selectively recovering metal cations from solutions according to claim 1, consisting of series-linked ion exchange columns, characterized in that the installation is made up of an ion-exchange cell containing two series-connected single-chamber columns (1, 2), each made of with the upper (3) and lower (4) plates to which the supply lines are connected, with controls for the distribution of the solutions mounted thereon. Installation according to claim 2, characterized in that the control elements are standard valves, valves and nozzles.