Extraction of molybdenum from aqueous solutions of wolframates

 

(57) Abstract:

The invention relates to the extraction of substances extraction and can be used in ferrous and nonferrous metallurgy, as well as treatment of industrial and domestic wastewater. The technical result is the extraction of molybdenum from aqueous solutions of wolframates extraction using inexpensive and effective extractant. The method of extraction of molybdenum from the acidic peroxide solutions wolframates carried out by extraction with a mixture of triallylamine (TAA) and isooctyl alcohol (IOS) in kerosene. Extraction of molybdenum from solutions of wolframates with the molar ratio of Mo:W1:100 carried out at pH 0, the volume ratio of aqueous and organic phases In:About=2,5-4,0, molar ratio of H2O2: (W+Mo)= 1-2, molar ratio of TAA:IOS:Mo:W=1:2:(0,04-0,06):(0,2-0,3). To prevent rapid deposition of tungsten acid from the acidic peroxide solutions, especially with a high content of molybdenum and the molar ratio of Mo: W1: 100, the extraction was carried out with ascorbic acid (AA), taken in the molar ratio AK:Mo=1:1. 2 C.p. f-crystals, 3 tab., 2 Il.

The method of extraction of molybdenum from aqueous solutions of wolframates refers to the extraction of substances extraction and tx2">

A known method of purification of aqueous solutions of wolframite by precipitation of poorly soluble trisulde molybdenum, based on the difference of the conditions of formation and the stability constants of the sulfosalts of molybdenum and tungsten [Izv. Non-ferrous metallurgy, 3, 1979, S. 97-103].

The disadvantages of the method are the hydrogen sulphide in the deposition of trisulde molybdenum, which requires the cost of disposal of gases, the need for heating solutions, this method does not provide deep cleaning and stain the solutions of sulfur.

The closest technical solution is the separation of tungsten and molybdenum by extraction with tributyl phosphate from acidic peroxide solutions [Voldman, M., Zelikman, A. N., Ziborov, N., Kagermann B. C. non-ferrous metallurgy, 3, 1978, S. 46-49].

The disadvantage of this method is its relatively high cost.

The objective of the invention is the extraction of molybdenum from aqueous solutions of wolframates extraction using inexpensive and effective extractant.

The technical result that can be achieved by carrying out the invention, lies in the efficiency and effectiveness of the removal process primelending from acidic peroxide solutions wolframates extraction as a solvent a mixture of triallylamine (TAA) and isooctyl alcohol (IOS) in kerosene.

Extraction of molybdenum from solutions of wolframates with the molar ratio of Mo: W1: 100 carried out at a pH of 0; the volume ratio of aqueous and organic phases In:About=2,5-4,0; molar ratio of N2ABOUT2:(W+Mo)=1-2; molar ratio of TAA:IOS: Mo:W=1:2:(0,04-0,06):(0,2-0,3).

To prevent rapid deposition of tungsten acid from the acidic peroxide solutions, especially with a high content of molybdenum and the molar ratio of Mo:W1:100, the extraction was carried out with ascorbic acid (AA), taken in the molar ratio AK:Mo=1:1.

The essence of the method is illustrated in table. 1-3 and Fig.1-2, in which the results are given of cleaning solutions wolframates from molybdenum by extraction using a mixture of TAA and IOS in kerosene.

It is known that in acidified aqueous solutions of ions of molybdenum and tungsten to form a mixed polyanion that at concentrations of molybdenum much smaller concentration of tungsten retain the properties and structure of polyvalent ions. Such solutions of amines extracted both metals.

When handling acidic solutions of hydrogen peroxide dissolved mixed polyanion, the metal contact in the individual complex compounds, their mutual influence weakens is adequate to maintain the high acidity of solutions. In addition, it is possible to recover ions of molybdenum (VI) and tungsten (VI) to lower oxidation States, primarily molybdenum, and reduced forms of molybdenum extracted amines better than tungsten.

Examples of specific implementation method.

Original solutions containing, g/DM3: 150 WO3and 1.2 Mo, were prepared by dissolution of crystalline Na2MeO42H2O (Me=W, Mo) mark H. h

As extractant used organic phase composition, wt.%: 6-8 TAA (R3NN)HE, where R=CH3(CH2)6CH2; 10-15 IOS C8H17OH, everything else is kerosene. In hydrometallurgy this extractant is used for the extraction of tungsten from solutions, pre-cleaned from impurities, including from molybdenum.

The concentration of ions of tungsten and molybdenum in aqueous solutions and the raffinate was determined by colorimetric and gravimetric methods, and extracts the difference between the initial concentrations and aqueous solutions. The results of extraction was evaluated by the distribution coefficient D, which was calculated as the ratio of equilibrium concentrations of extractable metal in the extract and the raffinate, the separation factor , rasschityvaet the u - as a percentage of the mass of metal in the extract and the original solution.

Extraction of molybdenum ions was carried out from hydrochloric peroxide solutions of sodium tungstate, for which the original solution was treated with 37% solution of hydrogen peroxide H2O2and then acidified with concentrated hydrochloric acid to a pH of 0. The choice of hydrochloric acid due to the fact that amines are better extracted with anionic chlorocomplexes.

During extraction, the pH was increased, so the specified pH value of 0 during the whole process was supported by the neutralization of hydrochloric acid with continuous stirring. The pH value was controlled by the pH - meter pH-121. At a higher value of pH extraction of molybdenum does not change, while the extraction of tungsten increases, which leads to the reduction of the coefficient of separation of metals, and at a lower value increases the consumption of acid and accelerates the deposition of tungsten and coprecipitation molybdenum acids.

Example 1 (table. 1-2, Fig. 1-2)

In table. 1 are given the results of extraction of molybdenum from aqueous solutions of wolframates when the molar ratio of Mo:W=1:100 and N2O2:(W+Mo)=1,76:1 in a volume ratio of the body is down 70 cm3the concentration, g/DM3:W 139,95; Mo 1,36; after adding peroxide and establishing pH 0 solution volume 93,3 cm3the concentration, g/DM3: W 105,00; Mo 1,02.

In Fig. 1 shows the dependence of the separation factor , and table. 2 - extract (%) metals from the phase relations of O:In, the other parameters remained the same as in terms of the experience table. 1.

In Fig. 2 shows the dependence of the extraction of metals ,%, molar ratio of N2ABOUT2:(W+Mo).

From the data of Fig. 1-2 and table. 1-2, it follows that the maximum separation factor = 56,06 obtained when the source correlation of phases O:=1:3 for 15 min (Fig. 1), thus removing the molybdenum wasMo=43,04%, and tungsten -W=1,38% (table. 1).

Saturation of the organic phase molybdenum occurs for 45 minutes and during this time, the extraction of molybdenum is 63,38%, tungsten and 4.4%, and the separation factor decreases to 38,05, but remains almost high enough, when this molar ratio was TAA:HOC:Mo:W=1:2:(0,04-0,06):(0,2-0,3).

The maximum recovery of molybdenumMo=81,4% obtained when A:B=1:2 during 30 minutes, while removing the tungsten wasW=28,17% (table.2).

From the data of Fig. 2 it follows that high the dependence of extraction of tungsten from the ratio of H2ABOUT2:(W+Mo) is an extreme character, at least extraction of tungstenW=1,38% 1.76 g-mol H2ABOUT21 g - atom of the amount of metals within 15 min of extraction. A further increase of hydrogen peroxide leads to more rapid precipitation of tungstic acid.

Experiments established that the increase in the content of molybdenum in the original tungsten solution also increases the deposition rate of tungsten acid from the raffinate.

Example 2 (table.3).

In table. 3 shows the comparative results of extraction with the use of ascorbic acid (weight ratio to molybdenum 1:1) and without it. The extraction was carried out with O:=1:2 and H2O2:(W+Mo)=1:1, the other parameters are similar to example 1.

From the data table. 3 shows that ascorbic acid significantly reduces the extraction of tungsten and increases the extraction of molybdenum toMo80%, retards the decomposition of H2O2and the deposition of tungsten acid, forming as hydrogen peroxide, private complexes with each of the metals separately, and also restores the molybdenum to a greater extent than tungsten. All these factors contribute to increased extraction of molybdenum is n from concentrated solutions of wolframates even by increasing the concentration of molybdenum in the solution of tungstate W:Mo100:1.

Reextraction metals can be ammonium, and alkaline solutions.

After a certain time of the raffinate begins to precipitate tungstic acid and two days is about 92% W, and only a little more than 40% of Mo. Thus, there is an additional cleaning of tungsten from molybdenum. The precipitated acid is lemon-yellow, according to x-ray phase analysis, has a crystalline structure and a well-washed and filtered.

Of the raffinate in the usual way, you can besiege paraformat ammonium (PVA).

Spectral analysis showed that the precipitated tungstic acid or PVA have very low molybdenum content, but rather high content of impurities of sodium and chlorine-ion battery that can be removed by presidenial.

After deposition of tungsten acid acidic solution containing hydrogen peroxide and hydrochloric acid (pH 0), can be used for the processing of tailings and waste, and for waste water and emissions of environmentally hazardous components.

The proposed method is compared with the prototype, more efficient, allows cleaning R>
Mo:W=1:100;

pH 0;

IN:O=2,5-4,0;

H2O2:(W+Mo)=1-2;

TAA:IOS:Mo:W=1:2:(0,04-0,06):(0,2-0,3).

1. The method of extraction of molybdenum from the acidic peroxide solutions wolframates extraction, characterized in that as a solvent, a mixture of triallylamine (TAA) and isooctyl alcohol (IOS) in kerosene.

2. The method according to p. 1, characterized in that the extraction of molybdenum from solutions of wolframates with the molar ratio of Mo: W1: 100 carried out at a pH of 0; the volume ratio of aqueous and organic phases In: About= 2,5-4,0; molar ratio of N2O2: (W+Mo)= 1-2; molar ratio of TAA: IOS: Mo: W= 1: 2: (0,04-0,06): (0,2-0,3).

3. The method according to p. 1, characterized in that the extraction of molybdenum from solutions of wolframates with the molar ratio of Mo: W1: 100 carry with ascorbic acid (AA), taken in the molar ratio AK: Mo= 1: 1.

 

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