The method of extraction of uranium from ores

 

(57) Abstract:

The invention relates to a hydrometallurgical methods of ore processing and can be used to extract uranium from ore materials by means of heap (KV) and underground (PV) leaching. The technical result - the reduction of costs and the intensification of the process of leaching. The method of extraction of uranium from ores by means of heap or underground leaching involves cooking leach solutions containing sulfuric acid, filtering them through the ore with the transfer of uranium, iron and other metals in the leachate and the extraction of uranium with obtaining uterine fluids. Leachate solutions are prepared by treating the aqueous phase with sulfur dioxide and oxygen-containing gas with the formation of sulfuric and sulfurous acids in leachate solutions support total concentration of sulphuric and sulphurous acids within 3-30 g/l, mostly 5-20 g/l, and the ratio of ion concentrations three - and divalent iron support is equal to or more than 0.5. 7 C.p. f-crystals, 2 tab.

The invention relates to a hydrometallurgical methods of ore processing and can be used to extract uranium from ore materials IU the DAMI PV and KB using sulfuric acid, the essence of which is to infiltration of dilute its solutions through a layer of ore stacked in a heap, either directly through the ore-bearing layer (Lunev L. N. Mine development system deposits of uranium underground leaching. - M.: Energoizdat, 1982, pp. 8, 13) [l].

The disadvantage of this method leaching is the low intensity of the process and, as a consequence, a large duration, increased consumption of acid, a large amount of productive solutions, subject to subsequent processing. Also used as a leaching agent sulfuric acid is relatively expensive reagent.

It is known that salts of trivalent iron contribute to the intensification of the process of leaching due to oxidation of U(IV) in the more soluble uranium U(VI) [1]. The role of such a catalyst can perform ions iron (II) contained in the circulating leach solutions (CTA), provided they are oxidized to the trivalent state by any oxidant. In practice, however, such a process does not exist due to the lack of effective oxidant.

There is also known a method of extraction of uranium from ores PV methods and KB, where oxidation is sinatora technological equipment (U.S. Pat. Of the Russian Federation No. 2172792) [2]. This method is the closest analogue to patentable inventions.

The disadvantage of this method [2] is that they require relatively expensive reagents nitric and sulphuric acids and equipment.

Task patentable invention is an improvement of the method of the leaching of uranium from ore by removing nitric acid and replacement of sulfuric acid more available reagent.

The technical result - the reduction of costs and the intensification of the process of leaching through the use of sulfur dioxide in combination with oxygen is provided by the fact that the method of extraction of uranium from ores by means of heap or underground leaching involves cooking leach solutions containing sulfuric acid, filtering them through the ore with the transfer of uranium, iron and other metals in the leachate and the extraction of uranium with obtaining uterine solutions according to the invention leachate solutions are prepared by treating the aqueous phase with sulfur dioxide and oxygen-containing gas with the formation of sulphuric and sulphurous acids, in leach solutions support total concentration of sulfuric and sulfurous acids in the limit is equal to or more than 0.5.

The method can be characterized by the fact that as the aqueous phase using natural formation water, leachate, uterine fluids, or a mixture thereof.

The method can be characterized also by the fact that sulfur dioxide is used in gaseous and/or liquid form.

The method can also be characterized by the fact that as the oxygen-containing gas using air and/or air enriched with oxygen, and/or technical oxygen.

The method can be characterized also by the fact that the concentration of sulfur dioxide in the oxygen-containing gas maintained within the range of 2-10%.

The method can be characterized by the fact that the aqueous phase is treated in the absorption apparatus.

The method can be characterized by the fact that the aqueous phase is treated with a gas by its ejection into the well.

The method can be characterized by the fact that sulfur dioxide is produced by burning elemental sulfur and/or sulfides of metals.

The basis of the method is the total chemical reaction

2Fe2++SO2+O2=2Fe3++SO2-4.

The technological essence of the method is that the leachate solutions are prepared by treating bookside sulfur and oxygen-containing gas. While sulfur dioxide is produced by burning elemental sulfur or kolchemanov (sulphides of metals) directly on the polygon PV or KV. The resulting sulfur dioxide is mixed with oxygen-containing gas (air, technical oxygen), keeping in mixture, the concentration of SO2within 2-10 vol.%. Then this gas mixture at ordinary temperature is treated with the aqueous phase in the absorption apparatus either directly in the borehole using the ejection of the gas.

As a result of interaction of sulfur dioxide with oxygen in the aqueous phase are formed sulfur and sulfuric acid in a concentration of from 5 to 20 g/l and at the same time, oxidation is contained in the CBR ions iron (II) with oxygen. The ratio of the concentrations of the ions Fe (III)/Fe(II) is 0.5 or more, which ensures oxidation of U(IV) in the ore to U(VI) and thereby intensifies the process of leaching of uranium in General.

This avoids delivery of sulphuric acid and nitric acid, prepared in the factory, to reduce the cost of reagents and transport, to support the intensification and simplification of the process as a whole.

Example 1. In chemical beaker 1 l is filled with 500 ml of an aqueous solution with a pH of the mixture, containing 2 vol.% SO2temperature - room. After a certain period of time selected samples processed in this way solution, determining the acid content and redox potential (E, mV). The results of the experiment are given in table. 1.

Are given in table.1 the values of E equal to 436 and 485 mV, corresponds to the ratio of Fe(III)/Fe(II) is between 0.46 and 0.65, respectively.

From the above table.1 the data shows that in the result of the interaction of sulfur dioxide and oxygen with the iron ions (II) in solution, increased its redox potential and acidity of a solution.

Example 2. In a column with a diameter of 35 mm load 350 g sandy ore natural size with a uranium content 0,209%. Ore soaked with water, “zachisliaut” weak acid solution of sulfuric acid. Then in column served with a speed of 80-100 ml / day solution containing 2-3 g/l of sulfuric acid and iron ions, obtained in example 1. At the outlet from the column daily take samples production solution, which determine the uranium content.

A similar method of conducting experience with a solution of sulfuric acid without the addition of iron (III). Raza is elatively solutions of ions Fe(III) (E=485 mV) provides a higher degree of extraction of uranium from ore PV method for all values of relations YF in comparison with the results obtained by leaching with a solution of one sulfuric acid.

Thus, based on the chemical characteristics of reagents used and the technological regime, stimulating the process of leaching of uranium methods PV and CV.

1. The method of extraction of uranium from ores by means of heap or underground leaching, comprising preparing leach solutions containing sulfuric acid, filtering them through the ore with the transfer of uranium, iron and other metals in the leachate, and the extraction of uranium with obtaining uterine fluids, characterized in that the leachate solutions are prepared by treating the aqueous phase with sulfur dioxide and oxygen-containing gas with the formation of sulphuric and sulphurous acids, with support in the leaching solution, the total concentration of sulphuric and sulphurous acids within 3-30 g/l, mostly 5-20 g/l, and the ratio of ion concentrations three - and divalent iron support is equal to or more than 0.5.

2. The method according to p. 1, characterized in that the aqueous phase using natural formation water, leachate, uterine fluids, or a mixture thereof.

3. The method according to p. 1 or 2, characterized in that djok who eat as oxygen-containing gas using air and/or air enriched with oxygen, and/or technical oxygen.

5. The method according to any of paragraphs.1-4, characterized in that the concentration of sulfur dioxide in the oxygen-containing gas maintained within the range of 2-10%.

6. The method according to any of paragraphs.1-5, characterized in that the aqueous phase is treated in the absorption apparatus.

7. The method according to any of paragraphs.1-5, characterized in that the aqueous phase is treated with a gas by its ejection into the well.

8. The method according to any of paragraphs.1-7, characterized in that the sulfur dioxide produced by burning elemental sulfur and/or sulfides of metals.

 

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FIELD: nonferrous metallurgy.

SUBSTANCE: invention aims at recovering uncommon metals from silicate ores and concentrates in processing of zirconium concentrates. Method according to invention envisages treating cake obtained by caking zircon concentrate with calcium oxide in presence of nitric or sulfuric acid. Concentrated acid is added to water-slurried cake at constant speed during 30-60 min in two steps so that 18-25% of acid is added during first 30 min, whereupon zirconium is leached at 80-90оС.

EFFECT: increased filtration velocity and simplified process due to reduced number of operations.

2 cl, 2 dwg, 4 ex

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