RU2150527C1 - Extraction plant for recovery of indium - Google Patents

Abstract

FIELD: metallurgy of nonferrous metals, particularly, recovery of indium as byproduct in processing of zinc concentrate by hydrometallurgical method with use of extraction process. SUBSTANCE: extraction plant has horizontal rectangular body separated by vertical partition into chambers of mixing and settling. Mixing of initial components is effected due to pulsation mixing with upper part of mixing chamber sizing 400-600 mm, angle of inclination of overflow trays ensuring overflow from mixing chamber to settling one of 4-6 deg, angle of inclination of perforated insert with two sloping surfaces in settling chamber equalling 5-15 deg. Using of extraction plant reduces content of indium in raffinate down to 3.1-4.5 mg/l. EFFECT: increased indium total recovery. 2 cl, 2 dwg, 3 tbl, 1 ex

Description

 The invention relates to the field of metallurgy of indium, in particular extraction extraction thereof from sulfate solutions of zinc production.

Known extraction plant using centrifugal extractors to extract indium from solutions (see V.I. Maltsev et al. "On the extraction technology of extracting indium from solutions of zinc production", "Non-ferrous metals" N 11, 1974 S. 19). However, these devices have a low degree of reliability (utilization rate 60-70%)
The closest in technical essence and the achieved result to the invention is an extraction plant for the extraction of rare metals, in particular indium, containing a horizontal rectangular housing, divided by a partition into a mixing and settling chamber.

 The mixture of aqueous and organic phases is carried out by a mixer. The resulting emulsion through the upper threshold of the septum is poured into the settling chamber. A <-shaped septum is installed on the flow path, whose edges are located at the level of the phase boundary. Continuing to move along the settling chamber, the emulsion is stratified into organic and aqueous phases. These phases merge through the outlet pipes located at different heights.

The disadvantage of this installation are:
- low degree of extraction of indium due to its high residual content in the raffinate. The raffinate is disposed of in zinc production, and indium is lost with the waste products - clinker (see Yu.A. Tsylov and S.A. Medvedev, A.S. N 405963 dated 11/20/1972 according to class C 22 B 59/00).

 The aim of the present invention is to reduce the irretrievable losses of indium with raffinate (increase its overall recovery).

An extraction plant for extracting indium is proposed. A distinctive feature of the proposed installation is that the phases are mixed due to pulsating mixing at a size of the upper part of the pulsation (mixing) chamber equal to 400-600 mm, and overflow trays in this chamber are located at an angle of 4-6 ^o in the direction of overflow. In addition, in the settling chamber there is a gable perforated insert with an angle of inclination of 5-15 ^o .

 An extraction plant for extracting indium consists of several mixing-settling cells. Each cell (see Fig. 1) is divided by a vertical partition (1) into a pulse chamber (mixing) - I and a settling chamber - II. In the mixing chamber, there is a compartment (A) for receiving the initial components and a pulsation compartment (B) for creating a pulsating motion of liquids. The pulsating (mixing) chamber contains: mixing and conveying nozzle devices (nozzles (2) and diffusers (3)), guides (4), a water seal (5) and overflow trays (6). In the settling chamber are two recirculating devices (7) and perforated inserts (8). At the end of the settling chamber there is a pipe (9) for overflowing the organic phase, in a perpendicular direction to which there is a pipe for overflowing the aqueous phase. Each cell has a pulsation pipe (10) and a “blow-off" pipe (11).

 Installation works as follows.

 The aqueous and organic phases by gravity come from pressure vessels to the receiving compartment of the pulsation (mixing) chamber. Further movement of the emulsion (a mixture of aqueous and organic phases) occurs due to pulsation.

A portion of compressed air is pulsed into the pulsating (mixing) chamber through a pipe (10). After the emulsion flows into the settling chamber (II), air is discharged through the “blow-off” pipe (11) into the atmosphere. When compressed air is supplied to the pulsation compartment through the nozzle (10), the liquid through the nozzles (2) and diffusers (3) is displaced into the mixing space of the pulsation (mixing) chamber, thereby ejecting liquid from the receiving compartment (A) due to the jet effect. Under the effect of this effect, the capture of the second phase by the liquid and mutual mixing of the flows occurs. The fluid flows are crushed and fall into the mixing space (height 400-600 mm) in the form of an emulsion. The level of emulsion in the mixing chamber rises and the emulsion flows through overflow trays, located at an angle of 4-6 ^o in the direction of overflow, into the settling chamber.

 The height of the upper part of the pulsation (mixing) chamber, equal to 400-600 mm, is determined on the basis of creating the optimal mixing of the components by ensuring the maximum pulsation frequency while maintaining a uniform and strictly vertical reciprocating motion of the emulsion.

 The latter is necessary to ensure complete contact of the initial components of the emulsion.

The angle of inclination of the overflow trays, equal to 4-6 ^o , is determined empirically and ensures the course of primary coalescence.

 In the settling chamber (II), phase separation occurs due to the forces of gravity and the difference in densities. The height of the liquid layer (aqueous and organic phases) in the settling chamber is determined by the level of the overflow pipe (9) of the organic phase.

 If necessary, the recirculation of the aqueous phase includes recirculation devices (7), which have valves that allow you to adjust the volume of recirculation.

In the settling chamber there is a gable perforated insert with an angle of inclination of 5-15 ^o . The specified angle of inclination provides high-quality separation (minimum indium content in the raffinate) of the phases due to the laminarization of the emulsion flow.

 The proposed installation is tested in an industrial environment. The tests showed that the proposed installation for the extraction of indium can virtually eliminate its loss with raffinate (to increase the degree of metal extraction).

 Information confirming the use of the proposed installation.

 Verification of the extraction unit was carried out as follows.

= 350-400 г/л) и хлористого натрия (С_NaCl= 25-30 г/л). После прохождения исходного индийсодержащего раствора и водного раствора (серная кислота + хлористый натрий) через камеру их смешения и последующего отстаивания в отстойной камере на выходе экстракционной установки получаем рафинат с остаточным содержанием индия 3-5 мг/л. и раствор сульфата индия (сод. индия 30-40 г/л), который направляется на его извлечение цементацией. Рафинат утилизируется в цинковом производстве.The initial solution, which is a chemical compound of indium with three monomers of di- (2-ethyl-hexyl) phosphoric acid at an indium concentration of 2.8-3.2 g / l, enters the extraction unit, where it is mixed with an aqueous solution of sulfuric acid

= 350-400 g / l) and sodium chloride (With _NaCl = 25-30 g / l). After passing the initial indium-containing solution and an aqueous solution (sulfuric acid + sodium chloride) through the mixing chamber and subsequent settling in the settling chamber at the outlet of the extraction unit, we obtain a raffinate with a residual indium content of 3-5 mg / l. and a solution of indium sulfate (soda. indium 30-40 g / l), which is sent to its extraction by cementation. Raffinate is recycled in zinc production.

 The table and example shows comparative data of the known extraction plant for the extraction of indium (prototype) and the proposed.

Example. The initial solution (indium 3.3 g / l) containing 39% of the indium compound with di- (2 ethylhexyl) phosphoric acid, the rest is a diluent, which is a mixture of synthetic fatty acids, at a speed of 1.0 m ³ / h extraction unit compartment. An aqueous solution of the composition is also sent to this compartment: sulfuric acid - 370 g / l, sodium chloride - 31 g / l. To create a pulsation, air is supplied under a pressure of 1.9 atm.

 The extraction unit has the device described above (see Fig. 1).

During the tests, the height of the pulsation (mixing) chamber varied in the range of 300-700 mm, the angle of inclination of the overflow trays changed from 3-7 ^o , and the angle of inclination of the gable perforated insert changed from 4 to 16 ^o .

 The products obtained as a result of extraction: raffinate and a solution of indium sulfate were sent respectively to the utilization and extraction of indium.

 In the same technological conditions, experiments were carried out on the prototype.

 As a prototype, a box extractor was used, the extraction cell of which is depicted in FIG. 2.

 The cell is divided by a vertical partition 1 into a mixing chamber 2 and a settling chamber. A mixer 4 and nozzles 5 and 6 are installed in the mixing chamber for supplying the solution. In the settling chamber there are nozzles 7 and 8 for draining the solutions and a distribution partition 9.

 The device operates as follows.

 The feed liquids are absorbed due to the vacuum generated by the mixer through the nozzles 5 and 6 into the mixing chamber 2, and are mixed with this mixer. The resulting emulsion through the upper threshold of the partition 1 is poured into the settling chamber 3. Encountering a partition 9 on the way, the edge of which is located at the interface, the emulsion flows around it and is distributed over the entire height of the settling chamber. Continuing to move along the settling chamber, the emulsion is stratified into organic and aqueous phases. The organic phase is discharged through the pipe 7, and the aqueous phase through the pipe 8. The pipes are in a special compartment and are equipped with devices for regulating the level of phase separation in the settling chamber.

 The results of the experiments are given in table. 1.

 From the above table. As can be seen from the data in Fig. 1, reducing the size of the pulsation (mixing) chamber to less than 400 mm does not provide sufficient contact time for the extractant (optimal mixing is not achieved) and the initial indium-containing solution, which increases its loss with raffinate from 4.0 to 42.2 mg / L. An increase in the size of the pulsation (mixing) chamber over 700 mm also leads to an increase in its losses with raffinate from 3.5 to 38 mg / l due to the inability to achieve effective phase separation.

From the above table. 2 data shows that reducing the angle of inclination of the overflow tray from 4 ^o to 3 ^o does not provide the required indium content in the raffinate (less than 5 mg / l), because this increases the dispersion of the emulsion components, and at the stage of sedimentation it is not possible to achieve the necessary coalescence. Increasing the angle of inclination of the overflow tray more than 6 ^o reduces the contact time of the extractant and the original indium-containing solution and increases its loss from 4.2-4.5 mg / l to 43.1 mg / l.

From the above table. 3 data shows that the creation of an inclination angle of the perforated insert less than 5 ^o does not reduce the indium content in the raffinate. However, due to the "clogging" of the insert with the organic phase, there is a need for frequent plant stops to clean it.

Increasing the angle of inclination of the perforated insert more than 15 ^o reduces the effect of the "additional" delamination surface, does not provide the necessary laminarization of the flow and increases the indium content in the raffinate from 3.8 to 21.6 mg / L.

 When implementing the prototype method, the indium content in the raffinate is high and is at the level of 62.0 mg / L.

 T. about. the use of the proposed extraction plant in comparison with the prototype allows to reduce the indium content in the raffinate from 62.0 mg / l to (3.1-4.5) mg / l and, as a result, increase its overall recovery by reducing irretrievable losses during disposal raffinates in zinc production.

Claims (2)

1. Extraction plant for extracting indium, containing a horizontal rectangular body, a vertical partition separating the body into a mixing and settling chamber, characterized in that the mixing chamber is made with a pipe for supplying compressed air for pulsating mixing in the upper part with a height of 400 - 600 mm mixing chamber and with overflow trays located at an angle of 4 - 6 ^o in the direction of overflow. 2. The extraction installation according to claim 1, characterized in that in the settling chamber there is a gable perforated insert with an inclination angle of 5 - 15 ^o .

Images