RU2260068C1 - Method of extraction of arsenic (+5) from acid sulfate solutions - Google Patents

Abstract

FIELD: technology of non-ferrous, rare and trace rare metals.

SUBSTANCE: proposed method includes extraction and separation of arsenic by organic extracting agent. Extracting agent is prepared from mixture of dialkyl methyl phosphonate in the amount of 40-70% with trialkyl amine in the amount of 20-30 vol-% and inert diluting agent in the amount of 10-30%. At extraction, arsenic changes to organic phase.

EFFECT: increased degree of extraction of arsenic (+5); enhanced selectivity and economical efficiency.

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Description

The invention relates to the technology of non-ferrous, as well as rare and trace metals, for example, to hydrometallurgical methods for processing copper, copper-zinc and copper-nickel arsenic-containing ores and intermediate products. The accumulation of arsenic (+5) in this case can occur at the stage of copper electrolysis. An increase in the content of arsenic (+5) in the electrolyte sharply worsens the quality of the cathode deposits and reduces the current efficiency during the electrolysis of the metal. Currently, extraction, precipitation and sorption methods are used to extract arsenic from acidic sulfate solutions. Using extraction methods can increase the degree of extraction of arsenic and increase the selectivity of the process of extraction of arsenic.

A known method of purification of sulfuric acid solutions from arsenic by extraction using tributyl phosphate as extractant (Giganov G.P., Travkin V.F., Kravchenko A.N. et al. // J. Inorgan. Chemistry. 1988. V.33. .8. S.2073-2079).

The disadvantages of this method are: a low degree of extraction of arsenic (+5) - not more than 90% even with a multi-stage process, high acidity of the initial aqueous solution, significant loss of organic reagent.

There is also known a method for the extraction of arsenic (+5) from sulfuric acid solutions using solutions of trialkylphosphine oxide in kerosene (Alguacil F.J. // Rev. Metal. Madrid. 1998. 34 (mayo). S.385-389). The disadvantages of this method are: the high cost of trialkylphosphine oxide, the low selectivity of the extractant for some impurities, for example, antimony, the high loss of sulfuric acid during extraction, the low efficiency of the re-extraction process using aqueous solutions of salts or water.

A known method of extraction of arsenic (+5) from acidic solutions using trialkylamine as an extractant (Mironova E.V., Glubokov Yu.M., Travkin V.F. // Non-ferrous metallurgy. 2002. No. 12. P.25-29 ) The disadvantages of this method is the effective extraction of arsenic (+5) is possible only with an acidity of the aqueous phase of not more than 60-80 g / l of sulfuric acid, as well as the need to use alkali solutions or solutions containing at least 150-200 g for reextraction of the arsenic / l sulfuric acid.

The closest to the proposed method in technical essence and the achieved result is the extraction method for the extraction of arsenic (+5) from sulfuric acid solutions using di-2-ethylhexylmethylphosphonate as an extractant (Travkin V.F., Glubokov Yu.M., Mironova E.V. Kravchenko A.N. // Non-ferrous metallurgy. 2001. No. 1. S.21-23). The disadvantages of this method are: a low degree of extraction of arsenic (+5) upon extraction from solutions with a sulfuric acid concentration of less than 100 g / l, a low rate of delamination of the organic and aqueous phases, low selectivity of the process during the extraction of arsenic (+5) from complex chemical composition technological solutions. These shortcomings lead to the need to use a large number of extraction apparatus during the implementation of the process and to increase the size of the main technological equipment - extractors. In this regard, the capital costs in the technology for the extraction of arsenic (+5) from production solutions are significantly increased.

The technical result of the present invention is:

1) an increase in the degree of extraction of arsenic (+5) in the organic phase;

2) increasing the selectivity of the process of extraction of arsenic (+5) and, in this regard, reducing the loss of sulfuric acid and other components during the process;

3) an increase in the rate of delamination of the organic and aqueous phases.

The specified technical result is achieved by the fact that in the known method for the extraction of arsenic (+5), including the extraction of arsenic by dialkylmethylphosphonate, 20-30% vol. trialkylamine and 10-30% inert diluent.

Thus, the use of the invention allows to increase the degree of extraction of arsenic (+5) from sulfuric acid solutions during extraction, to increase the selectivity of the process, which will reduce the loss of sulfuric acid and other components of complex technological solutions, as well as increase the rate of delamination of the organic and aqueous phases. This will increase the efficiency of the extraction process of arsenic extraction (+5) and reduce the costs required to implement the process.

The essence of the proposed method is illustrated by the following examples.

Example 1

The extraction of arsenic (+5) is carried out from an aqueous sulfate solution containing 6.9 g / l of arsenic at various concentrations of sulfuric acid. As an extractant, a solution in kerosene of 50% vol. dioctylmethylphosphonate (DOMF) and 20% vol. triisooctylamine (ThIOA), as well as 50% vol. DOMF solution in kerosene and 30% vol. Thioa in kerosene. Extraction is carried out with a volume ratio of organic and aqueous phases O: B = 1: 1, a temperature of 22.8 ° C and a phase contact time of 3 minutes. Table 1 shows data on the effect of the acidity of the aqueous phase on the extraction of arsenic (+5) in the organic phase.

Table 1 Effect of sulfuric acid concentration on arsenic extraction (+5) The concentration of sulfuric acid, M Arsenic distribution coefficient (+5) 50% vol. DOMF in kerosene (prototype) 30% vol. Tioa in kerosene 50% vol. DOMF + 30% vol. TiOA + 20% vol. kerosene 3.0 2.6 0.05 2,8 2.0 2.1 0,07 2,3 1,5 1,1 0.1 2.6 1,0 0.9 0.4 2,8 0.8 0.8 1.2 3.2 0.5 0.1 1,6 3,5 0.3 0.2 0.9 3,1 0.2 0.1 0.8 2,3 0.1 0.06 0.5 1.8 0.05 0.01 0.3 1.4

From the data given in Table 1, it can be seen that when using a mixture of dialkylmethylphosphonate and trialkylamine as an extractant, the recovery of arsenic (+5) is higher than DOMP, especially when extracted from solutions with a sulfuric acid concentration of less than 100 g / l.

Example 2

Arsenic (+5) is extracted from sulfuric acid solutions containing 6.7 g / l of arsenic and 50.6 g / l of sulfuric acid. The extractant is a mixture of dioctyl methylphosphonate (DOMP) and tri-isooctylamine (ThIOA) in an inert diluent (kerosene or toluene) at a different ratio of components. The extraction is carried out at a ratio of O: B = 1: 1, a temperature of 23.1 ° C and a phase contact time of 3 minutes (see table 2).

table 2 The influence of the composition of the extractant on the extraction of arsenic from sulfate solutions The composition of the extractant (% vol.) Partition coefficient D _As when used as a diluent DOMF Tioa Kerosene Toluene kerosene Toluene 0 thirty 70 70 1,6 1,54 twenty thirty fifty fifty 1.8 1.7 thirty thirty 40 40 1.9 2.0 40 thirty thirty thirty 3,5 3.4 fifty 25 25 25 3.6 3,7 fifty thirty twenty twenty 3,5 3.6 60 thirty 10 10 3.4 3.3 60 twenty twenty twenty 3.2 3.2 70 twenty 10 10 2.9 2,8 80 10 10 10 1.3 1,2 90 10 0 0 1,0 0.95 100 0 0 0 0.7 0.66

From the data given in Table 2, it follows that the extraction of arsenic (+5) in the organic phase increases in the following range of concentrations of the components of the extracting mixture: 20-30% vol. Thioa and 10-30% vol. an inert diluent, the rest is dialkylmethylphosphonate (DOMP).

Example 3

Arsenic is extracted from aqueous solutions containing 50 g / l of sulfuric acid and 3.5 g / l of arsenic (+5). As an organic phase, a solution in kerosene of 50% vol. DOMF and 30% vol. Tioa. Productivity by the sum of the flows of organic and aqueous phases with a ratio of O: B = 1: 1 reaches 3.9 m ³ / m ² · hour. In the case of using undiluted DOMF as the organic phase, the productivity by the sum of the phases under these conditions will be 1.1 m ³ / m ² · hour, and in case of using 50% vol. DOMF - 2.1 m ³ / m ² · hour.

Thus, the use of a mixture of dialkylmethylphosphonate and aliphatic amine in kerosene as an extractant makes it possible to increase the rate of phase separation and, therefore, the productivity of extraction equipment.

Example 4

The extraction of arsenic (+5) is carried out from solutions containing (g / l): arsenic (+5) 5.8; sulfuric acid - 69.0; copper (+2) - 15.3; nickel (+2) - 10.2; antimony (+3) - 1.5; iron (+3) - 2.1; iron (+2) - 1.6. As extractants, a mixture in kerosene DOMF and ThIOA, 100% DOMF and a solution in kerosene ThIOA are used. Extraction conditions: O: B ratio 1: 1, phase contact time 3 min, temperature 23.2 ° C (see table 3).

Table 3 Distribution of components between phases during the extraction purification of sulfuric acid solution from arsenic (+5) Solution component Recovery% 100% DOMF (prototype) 30% vol. TiOA + 70% vol. kerosene 50% vol. DOMF + 30% vol. TiOA + 20% vol. kerosene Arsenic 43,2 52,4 76.0 Sulfuric acid 12.3 8.3 2.9 Copper 0.5 0.42 0.05 Nickel 0.4 0.51 0.06 Antimony 1.3 1,5 0,07 iron (+3) 0.25 0.32 0.06 iron (+2) 0.21 0.19 0.02

The results shown in table 3 indicate a higher selectivity of the arsenic extraction process (+5) with a mixture of dialkylmethylphosphonate and trialkylamine compared to the prototype.

Example 5

The extraction of arsenic (+5) is carried out in accordance with the conditions of Example 2. Solutions of kerosene dioctyl methylphosphonate (DOMP), di-isoamyl methylphosphonate (DAMP), trialkylamine C ₇ -C ₉ (TAA), and tri-n-octylamine are used as the organic phase. TOA) and tri-isooctylamine (ThIOA) (see table 4).

Table 4 The effect of the nature of the extractant on the extraction of arsenic (+5) from sulfate solutions The concentration of sulfuric acid, M Arsenic distribution coefficient 50% vol. DAMP, 30% vol. Tioa, 20% vol. kerosene 50% vol. DAMP, 30% vol. TOA, 20% vol. kerosene 50% vol. DOMF, 30% vol. TOA, 20% vol. kerosene 50% vol. DOMF, 30% vol. TAA, 20% vol. kerosene 3.0 2,8 2.6 2.9 2.7 2.0 2,4 2.3 2,5 2.6 1,5 2,5 2.7 2.6 2.9 1,0 3.0 2,8 2.9 2.8 0.8 3,1 3.2 3.3 3,1 0.5 3.6 3,7 3.6 3,5 0.3 3.0 3,1 2.9 3.0 0.2 2,3 2.5 2,4 2,5 0.1 1.7 1.9 1,6 1.8 0.05 1,5 1.3 1.4 1.3

From the data given in Table 4, it can be seen that the use of dialkylmethylphosphonates and trialkylamines having a different structure of alkyl radicals does not affect the efficiency of the arsenic extraction process (+5).

Example 6

A countercurrent extraction process for the extraction of arsenic (+5) is carried out from an aqueous solution containing 7.43 g / l of arsenic and 62.4 g / l of sulfuric acid. As the organic phase, a solution in kerosene DOMP and ThIOA or 100% DOMP (prototype) was used. Re-extraction of arsenic from the organic phase is carried out with water or an aqueous solution of 100 g / l Na ₂ SO ₄ (during extraction with 100% DOMP). The extraction and reextraction processes were carried out at a temperature of 22-23 ° C. The process conditions and the obtained experimental results are given in table 5.

Table 5 Key indicators of the process of extraction of arsenic (+5) from sulfate solutions Indicator The proposed method Prototype The composition of the extractant 50% vol. DOMF, 20% vol. Thioa, 30% vol. kerosene 100% DOMF EXTRACTION Number of countercurrent stages 4 6 Ratio A: B 1.5: 1 1.5: 1 Arsenic content in raffinate 0.55 2.42 The recovery of arsenic (+5),% 92.6 67.8 Extraction of sulfuric acid,% 3,5 12.3 Reextraction The composition of the stripping solution Water 100 g / l Na ₂ SO ₄ Number of countercurrent stages 4 4 O: B ratio 3: 1 3: 1 The recovery of arsenic (+5) in re-extract,% 99.1 97.3 Extraction of sulfuric acid in re-extract,% 98.7 97.6 Loss of extractant, g / l of the original aqueous solution 0.06 1,5

A review of the data indicates that the extraction of arsenic (+5) in the present method is higher than in the method of the prototype. The operation of arsenic re-extraction (+5) can be carried out with water, while in the case of using undiluted DOMP (prototype), it is necessary to use aqueous solutions of reagents, for example, sodium sulfate, to separate the organic and aqueous phases. In addition, the use of the proposed method allows to increase the selectivity of the process of extraction of arsenic (+5) and to reduce, due to this, the loss of sulfuric acid and other components of technological solutions. The possibility of using the process of extraction of arsenic with an acidity of the aqueous phase of less than 100 g / l reduces the cost of reagents. Finally, an increase in the rate of delamination of the organic and aqueous phases can reduce the cost of extraction equipment and reduce the loss of organic reagents with aqueous solutions.

Claims (1)

An extraction method for the extraction of arsenic (+5) from acid sulfate solutions, including extraction with dialkylmethylphosphonate, characterized in that 20-30 vol.% Trialkylamine and 10-30% inert diluent are introduced into the extractant.