RU2824150C1 - Method of extracting vanadium from spent catalysts of sulfuric acid production - Google Patents

Abstract

FIELD: chemical or physical processes.

SUBSTANCE: invention relates to hydrometallurgical processes for extracting vanadium from spent vanadium catalysts (SVC) of sulfuric acid production and vanadium-containing ores. Method involves staged percolation leaching of vanadium in an acidic medium in the presence of a reducing agent to obtain a productive solution for leaching vanadium. Pulp with pH 1.5–2.0 is formed by interaction of productive solution of vanadium leaching and suspension, obtained by combined wet grinding of manganese concentrate and calcium carbonate, its thickening and acidification to pH 4–6. Vanadium is sorbed by anionite from the obtained pulp, in which vanadium is oxidised. Ammonia-nitrate desorption of vanadium is carried out at pH 9.0–9.5, anionite is converted from a nitrate form to a sulphate form with a solution of sulfuric acid. Anionite is washed from acidity and fed for sorption, precipitation from the obtained ammonium metavanadate desorbates, its filtration, drying, disintegration and calcination to obtain vanadium pentoxide.

EFFECT: method increases quality of the obtained vanadium pentoxide while ensuring content of V₂O₅ in the end product of more than 99%.

1 cl, 1 dwg, 1 tbl

Description

The invention relates to hydrometallurgical processes for extracting vanadium from spent vanadium catalysts and vanadium-containing ores.

A method for processing vanadium-containing raw materials is known, including staged percolation sulfuric acid leaching of vanadium and its sorption from the resulting productive solutions. The disadvantages of this known method include low extraction of vanadium, due to the absence of a reducing agent in the leaching solution (Patent of the Russian Federation No. 2374344, published on 27.11.2009, Bulletin No. 33).

A method for extracting vanadium from spent catalyst is also known, by leaching it with an acidic sulfate-containing solution in the presence of hydrazine sulfate, supplied at a rate of 1-2% of the catalyst weight. Its disadvantages include high consumption of expensive reducing agent (USSR Author's Certificate No. 1381069, published 15.03.1988).

The closest in technical essence to the claimed method is a method for extracting vanadium from spent catalysts of sulfuric acid production, including multi-stage leaching of the catalyst with an alkali metal hydroxide at atmospheric pressure in the temperature range from 0 to 90°C, preferably at 20°C, followed by obtaining ammonium metavanadate from the leaching solution (Patent DD 276672 A, B01J 0023/84, published 03/07/1990).

The disadvantage of the known method is the relatively low quality of the resulting product.

The objective of the claimed invention is to extract vanadium from spent catalysts of sulfuric acid production using a method that ensures high quality of the resulting vanadium pentoxide.

The stated problem is solved in that the extraction of vanadium from spent catalysts of sulfuric acid production is carried out by a method including staged percolation leaching of vanadium in an acidic medium in the presence of a reducing agent, oxidation of vanadium transferred to the liquid phase, sorption of vanadium by anion exchanger at pH 1.5-2.0, ammonium-nitrate desorption of vanadium, conversion of the anion exchanger from nitrate form to sulfate form with a solution of sulfuric acid, washing the anion exchanger from acidity and feeding it for sorption, precipitation of ammonium metavanadate from the obtained desorbates, its filtration, drying, disintegration and calcination with the production of vanadium pentoxide, while the sorption of vanadium is carried out from the pulp formed by the interaction of the productive solution of vanadium leaching and the suspension obtained by joint wet by grinding manganese concentrate and calcium carbonate, thickening it and acidifying it to pH 4-6, ammonium-nitrate desorption of vanadium is carried out at pH 9.0-9.5.

Thus, the main distinguishing features of the claimed method are the following:

- vanadium sorption is carried out directly from the formed pulp, and not from the productive vanadium leaching solution;

- the formation of the pulp sent for sorption is carried out by the interaction of the productive solution of vanadium leaching and the suspension obtained by the joint wet grinding of manganese concentrate and calcium carbonate, its thickening and acidification to pH 4-6;

-ammonia-nitrate desorption of vanadium is carried out, in comparison with the pH in the known method - 8.5, at higher ammonia content - in the boundary values of pH 9.0-9.5.

The technical result of the claimed method is a reduction in the costs of producing a vanadium product and ensuring high quality of the resulting vanadium pentoxide.

The developed technology was initially tested in laboratory conditions, then semi-industrial tests were conducted. The essence of the invention is explained in the attached drawing - a basic technological scheme of the process of extracting vanadium from spent catalysts of sulfuric acid production.

The basic technological scheme of the process of vanadium extraction from spent catalysts of sulfuric acid production includes a two-stage percolation leaching of vanadium from the spent catalysts of sulfuric acid production in an acidic medium (pH 0.8-1.2) in the presence of a reducing agent (hydrazine, at a rate of 1.0-1.5 kg/t) to obtain a productive solution, joint wet grinding of manganese concentrate (containing ~40% MnO ₂ as an oxidizing agent) and calcium carbonate, which is chalk or limestone. The resulting suspension is thickened, acidified to pH 4-6 and then fed to interact with the productive solution of vanadium leaching, forming a pulp with a pH of 1.5-2.0, in which vanadium is oxidized. Next, it is sent to a five-stage sorption of vanadium by anion exchanger moved countercurrent to the movement of the pulp. The saturated sorbent is separated from the pulp by screening, washed from sludge with water and fed to desorption, carried out by ammonium nitrate in an ammonia medium at a ratio of the volumes of the anion exchanger and eluent of 1:2 and a residual content of nitrate ions in the desorbate at the level of 10-20 g / l. The desorbed anion exchanger is converted into a sulfate form with a solution of sulfuric acid (with a concentration of 150-170 g / l for H ₂ SO ₄ at a ratio of the volumes of the solution and anion exchanger of 2: 1), washed with water to remove acidity and sent to the tail apparatus of vanadium sorption. From the resulting desorbates, ammonium metavanadate is precipitated, filtered, dried, disintegrated and fed for calcination. The final product of the process is vanadium pentoxide.

During the experimental work, the combined wet grinding of manganese concentrate and calcium carbonate was carried out in a 1:1 ratio in a ball mill. For the sorption extraction of vanadium from the pulp, the BESTION D299 anion exchanger was used. As sorption devices in semi-industrial conditions, pachucas with air mixing were used, the saturated anion exchanger was washed from sludge in a KRIMZ column, and vanadium was desorbed in a PIK column.

Drying of ammonium metavanadate was carried out at a temperature of 100-120°C, and its calcination, to obtain V ₂ O ₅ , was carried out at 670-680°C.

The results of laboratory studies and pilot tests on the extraction of vanadium from HVAC are presented in the table.

Conditions for conducting experimental work Initial vanadium content in the OVK,
% 1st stage of percolation leaching 2nd stage of percolation leaching Yield of leached solid phase from the initial mass of the OVK, % Vanadium content in leached OWC matrix,
% Ratio
MnO2 to CaCO3,
kg/kg pH
pulps
on sorption,
pH units Vanadium desorption Extraction of vanadium into finished products,
% Content of V ₂ O ₅ in finished products,
% Time, hour pH, pH units ORP,
IN Time, hour pH, pH units ORP, B NO ₃ ,
g/l pH, pH units Laboratory
research 4.3 36 0.9-1.0 0.70 18 0.8-0.9 0.71 0.6 0.56 1:1 1.5-2.0 120 9.3 92.2 99.4 Semi-industrial testing 4.2 24 1.1-1.3 0.68 12 0.8-1.0 0.70 0.7 0.90 1:1 1.6-1.8 118 9.0-9.5 85.0 99.2 120 8.5 85.0 97.1

It follows from them that the patented method made it possible to achieve _V2O5 content values in the final product of _99.2-99.4 %.

Thus, the conducted experimental work has shown that the proposed method for extracting vanadium from spent catalysts of sulfuric acid production provides a significant increase in the quality of the resulting vanadium pentoxide.

Claims (1)

A method for extracting vanadium from spent catalysts of sulfuric acid production, including staged percolation leaching of vanadium in an acidic medium in the presence of a reducing agent to obtain a pregnant vanadium leaching solution, forming a pulp with a pH of 1.5-2.0 by interaction of the pregnant vanadium leaching solution and a suspension obtained by joint wet grinding of manganese concentrate and calcium carbonate, thickening and acidifying it to a pH of 4-6, sorption of vanadium by an anion exchanger from the obtained pulp, in which vanadium is oxidized, ammonium-nitrate desorption of vanadium at a pH of 9.0-9.5, conversion of the anion exchanger from nitrate form to sulfate form with a sulfuric acid solution, washing the anion exchanger from acidity and feeding it for sorption, precipitation of metavanadate from the obtained desorbates ammonium, its filtration, drying, disintegration and calcination to obtain vanadium pentoxide.