RU2100466C1 - Method for recovering manganese from manganese-containing concentrates - Google Patents

Abstract

FIELD: metallurgical industry. SUBSTANCE: proposed method comprises conventional process steps of leaching feed concentrates with sulfuric acid to obtain precipitate and manganese-containing liquor, treating liquor, and recovering manganese therefrom. Inventive novelty of proposed method resides in following: feed concentrates contain manganese and vanadium and leaching is carried out in two steps: pH value in first step is maintained at 1.8-2.5, while in second step pH is 1.0-1.4. To adjust pH in second step, lime-and-sulphur-containing liquid is added. Liquor resulting from first leaching step, prior to recovering manganese from it, is treated by passing it through anion-exchange resin. Liquor left over after second step is recycled back to first leaching step. EFFECT: good manganese recoveries from hard-to-process feed concentrates.

Description

 The invention relates to the field of non-ferrous metallurgy, to methods for processing manganese concentrates containing vanadium.

A known method of processing manganese raw materials with sulfuric acid with the introduction of a metal alloy reducing agent containing iron and manganese, followed by adjustment to pH 4.5, filtering the precipitate of calcium sulfate and the separation of manganese concentrate from the sulfate solution [1]
When processing manganese-vanadium-containing concentrates by this method, manganese contaminated with vanadium is released from the solution. In addition, the separated precipitate of calcium sulfate also contains impurities of vanadium and iron and is not a finished product.

A known method of processing manganese raw materials, in which a manganese-containing suspension is treated with sulfuric acid in conjunction with ammonium sulfate, a metal reducing agent containing manganese and iron is introduced to establish a pH of 1.8 to 2.0 to obtain an ammonium sulfate solution of manganese, and the resulting solution is purified from impurities , electrolytic manganese with regeneration of ammonium sulfate and sulfuric acid is obtained from the purified solution [2]
The quality of the final products of manganese oxide and calcium sulfate obtained by applying the method and processing manganese-vanadium-containing concentrates is low due to their contamination with impurities of vanadium and iron.

The closest in technical essence to the present invention is a method for producing manganese concentrates, including leaching manganese from manganese-containing raw materials with sulfuric acid to pH 1.5, neutralizing the resulting solution to pH 4.5, separating the manganese-containing solution from the solid phase containing calcium sulfate, introducing a manganese-containing solution of polyacrylic and polymethacrylic acid or their sodium or potassium salts in an amount equal to 10 500 mg per 1 kg of concentrate, precipitation of manganese concentrate [ 3]
The disadvantage of this method is that the separated solid precipitate of calcium sulfate is not commercial gypsum, as it contains a significant amount of impurities.

 When processing manganese-vanadium-containing concentrates using this technology, it is impossible to obtain a high-purity manganese product, since vanadium is converted into a manganese product during the deposition process. In addition, part of the manganese and vanadium remains in gypsum sediment, which also does not allow to obtain a marketable product.

 The technical result of the invention is to obtain a high-purity manganese product and marketable calcium sulfate (gypsum).

 This is ensured by a method for processing manganese vanadium-containing concentrates, including leaching with sulfuric acid in 2 stages at pH values in the first stage of 1.8 2.5 and in the second 1.0 1.4, and in the second stage lime-sulfur broth is introduced to obtain a precipitate and a manganese-containing solution, processing the resulting solution by passing through an anion-exchange resin and subsequent separation of manganese from it, and the solution after the second stage is sent to the first leaching stage.

 The essence of the proposed method is as follows.

In manganese concentrates containing vanadium, there are compounds of two-, three- and tetravalent manganese, and part of the manganese in the form of vanadates Mn ₂ V ₂ O ₇ . Vanadium is also represented by oxides. The main factor restraining the transfer of manganese into the solution is the low solubility of the compounds Mn ³⁺ and Mn ⁴⁺ , while the compounds Mn ^{2+ are} well transferred to the solution.

According to the proposed method, leaching is carried out in 2 stages. To transfer the main part of manganese and vanadium into the solution, the first leaching stage is carried out in the range of pH 1.8 2.5. This interval is necessary and sufficient for Mn ^{2+ to} go into the solution in the form of sulfate, and the main part of V ⁵⁺ goes to the solution in the form of decavanadic acid.

In addition, manganese decavanadates Mn ₂ V ₂ O ₇ , interacting with sulfuric acid in this pH range, form well-soluble protonated manganese pyrovanadate MnH ₂ V ₂ O ₇ .

The precipitate from the 1st leaching stage, containing CaO ₄ , under-extracted manganese and vanadium, is subjected to repeated leaching. The second leaching stage is carried out in a more acidic region at pH 1.0 to 1.4 with the introduction of a lime-sulfur broth. When leaching with sulfuric acid with the addition of a lime-sulfur broth, the compounds Mn ³⁺ and Mn ⁴⁺ , interacting with a lime-sulfur broth, are reduced to Mn ²⁺ and transferred to the solution.

Along with this, the sparingly soluble compounds of V ^5+, which were not recovered at the first stage of leaching, also interact with a calcareous broth, and V ⁵⁺ transforms into a tetravalent form. The presence of V ⁴⁺ ions with a higher reactivity in the solution additionally contributes to the destruction of the Mn ³⁺ and Mn ⁴⁺ compounds and the transition of manganese into the solution.

 Calcium of lime-sulfur broth in the form of calcium sulfate passes into the precipitate, enriching it with calcium. The obtained precipitate of calcium sulfate does not contain impurities of vanadium and manganese and is a ready-made commercial product. A solution of manganese sulfate from stage 2 leaching is wrapped in stage 1.

When carrying out 2 leaching stages at a pH of more than 1.4, the region of hydrolytic precipitation of vanadium occurs, which will lead to contamination of the precipitate of calcium sulfate with vanadium and will not allow to obtain marketable gypsum. In addition, at pH 1.4, the conditions for the reduction of Mn ³⁺ and Mn ^{4+ are} worsened, which reduces the degree of manganese extraction and also gypsum sediment is contaminated.

 A decrease in pH of 1.0 is not economically feasible, since it does not improve performance with increasing consumption of sulfuric acid.

The solution after the first leaching step containing the compounds Mn ²⁺ and V ⁵⁺ is treated by passing through an anion exchange resin. In this case, vanadium completely settles on the resin, and high-purity manganese oxide is obtained from the manganese solution by precipitation.

 Thus, the proposed method for processing manganese-vanadium-containing concentrates allows you to selectively select all valuable components and obtain a high-purity manganese product and commercial gypsum.

 Example 1

Manganese-vanadium-containing concentrate in an amount of 200 g, containing, by weight. MnO-14.5, CaO-18.3, V ₂ O ₅ -4.8 were leached in two stages. In the first stage, it was mixed with a sulfuric acid solution obtained in the second leaching stage, containing, g / l: manganese 10.2, vanadium 3.6 at T: W 1: 2 with the addition of sulfuric acid to a pH of 1.8, leached for 1 h at 70 ^o C.

 The manganese-containing solution was separated from the solid phase by filtration, the filtrate contained, g / l: manganese 53.5, vanadium 12.7, calcium 0.4. The resulting solution was passed through an anion exchange resin AMP. The solution after sorption contained, g / l: manganese 53.5, vanadium 0.001.

The precipitate after the first stage of leaching with sulfuric acid at a pH of 1.0, T: W 1: 2, a temperature of 70 ^o C, in the process of leaching was introduced an aqueous solution of lime-sulfur broth obtained at T: W 1: 4 by mixing calcium oxide and sulfur elemental in a ratio of 1: 1.2 when heated, in an amount of 50 ml.

The solution was separated from the solid phase by filtration. The filtrate with a content of, g / l: manganese 10.2, vanadium 3.6, calcium 0.2, was sent to the first leaching stage. The precipitate was washed at T: W 1: 2, filtered, dried. The final product commercial gypsum, contained, wt. calcium 24.0, manganese 0.1, vanadium 0.1. 99.5% recovery in commercial gypsum
To precipitate manganese concentrate into the manganese solution after sorption of vanadium, ammonium bicarbonate was added with stirring in a 1.2-fold excess of stoichiometrically necessary. The deposition time was 1 hour. The manganese concentrate was separated from the mother liquor by filtration, washed with repulpation at a ratio of T: W 1: 2, again filtered, dried, and calcined. The final product contained high-purity manganese concentrate, wt. manganese 77.4, vanadium 0.01, calcium n / v. 99.4% Manganese Recovery
Example 2

200 g of manganese-vanadium-containing concentrate with a mass fraction of MnO 12.8, CaO 17.5, V ₂ O ₅ 4.1 leached in two stages. In the first stage, it was mixed with a sulfuric acid solution obtained in the second leaching stage, containing, g / l: manganese 8.9, vanadium 3.1, calcium 0.2 at T: W 1: 2 with the addition of sulfuric acid to pH 2, 1, leached 1 h at 70 ^o C.

 The manganese-containing solution was separated from the solid phase by filtration. The filtrate contained g / l: manganese 47.1, vanadium 10.9, calcium 0.35. The resulting solution was passed through an anion exchange resin. The solution after sorption contained g / l: manganese 47.1, vanadium 0.001.

The precipitate after the first stage was leached with sulfuric acid at a pH of 1.2, T: W 1: 2, a temperature of 70 ^o C, during the leaching process, 48 ml of lime-sulfur broth was introduced.

The solution was separated from the solid phase by filtration. The filtrate with a content of, g / l: manganese 8.9, vanadium 3.1, calcium 0.2, was sent to the first stage of leaching. The precipitate was washed at T: W 1: 2, filtered, dried. The final product commercial gypsum, contained, wt. calcium 23.9, manganese 0.1, vanadium 0.1. 99.6% recovery in commercial gypsum
To precipitate manganese concentrate into the manganese solution obtained after sorption of vanadium, ammonium bicarbonate was added with stirring in a 1.2-fold excess of stoichiometrically necessary. The deposition time was 1 hour. The manganese concentrate was separated from the mother liquor by filtration, washed with repulpation at a T: W ratio of 1: 2, again filtered, dried, and calcined. The final product is high-purity manganese concentrate, contained, wt. manganese 77.41, vanadium 0.01, calcium n / v. 99.65% Manganese Recovery
Example 3

200 g of manganese-vanadium-containing concentrate with a mass fraction of MnO 14.5, CaO 18.3, V ₂ O ₅ 4.8 were leached in two stages. In the first stage, it was mixed with a sulfuric acid solution obtained in the second leaching stage, containing, g / l: manganese 11.8, vanadium 3.85, calcium 0.25, at T: W 1: 2 with the addition of sulfuric acid to pH 2 , 5, leached 1 h at 70 ^o C.

 The manganese-containing solution was separated from the solid phase by filtration. The filtrate contained, g / l: manganese 53.6, vanadium 12.8, calcium 0.45. The resulting solution was passed through an anion exchange resin AMP. The solution after sorption contained, g / l: manganese 53.6, vanadium 0.001.

The precipitate after the first stage of leaching with sulfuric acid at a pH of 1.4, T: W 1: 2, a temperature of 70 ^o C, in the leaching process was introduced 52 ml of lime-sulfur broth.

The solution was separated from the solid phase by filtration. The filtrate with a content of, g / l: manganese 11.8, vanadium 3.85, calcium 0.25, was sent to the first stage of leaching. The precipitate was washed at T: W 1: 2, filtered, dried. The final product commercial gypsum, contained, wt. calcium 23.95, manganese 0.15, vanadium 0.1. 99.5% recovery in commercial gypsum
To precipitate manganese concentrate into the manganese solution obtained after sorption of vanadium, ammonium bicarbonate was added with stirring in a 1.2-fold excess of stoichiometrically necessary. The deposition time was 1 hour. The manganese concentrate was separated from the mother liquor by filtration, washed with repulpation at a T: W ratio of 1: 2, again filtered, dried, and calcined. The final product is high-purity manganese concentrate, contained, wt. manganese 77.42, vanadium 0.01, calcium n / v. Manganese recovery was 99.5

Claims (1)

 A method for extracting manganese from manganese-containing concentrates, including leaching with a sulfuric acid solution to obtain a precipitate and a manganese-containing solution, processing the resulting solution and subsequent separation of manganese from it, characterized in that manganese-vanadium-containing concentrates are leached, it is carried out in two stages at a pH of 1.8 in the first stage of 1.8 2.5 and the second 1.0 1.4, and in the second stage, a lime-sulfur broth is introduced, the solution obtained after the first stage and before the separation of manganese from it, processing by passing through an anion exchange resin and solution from the second stage is directed to the first leaching stage.