DE1018038B - Process for the production of pure niobium compounds - Google Patents

Description

Process for the production of pure niobium compounds It is known Ores, concentrates, slags, metals and the like containing tantalum and niobium. to process the like, by digesting these raw materials with hydrofluoric acid or through. Treatment with elemental Chlorine (in the case of oxidic raw materials with the simultaneous use of reducing agents like coal and carbon monoxide) are converted into chlorides and dissolve them in strong hydrochloric acid. Both hydrofluoric acid and hydrochloric acid solutions also contain niobium and tantalum the accompanying impurities titanium, tungsten, tin, iron and the like in solution. The Tanta, l with ketones, preferably can be obtained from such complex solutions with methyl isobutyl ketone, so that a largely tantalum-free Niobium solution, which, however, contains all the impurities titanium, tungsten, tin, iron and the like. Remains. Should a niobium compound from such a solution To be extracted with Ke.ton, it is necessary to determine the acid concentration essential to increase what is required, highly concentrated, uncomfortable to use Acids to use. There. at these required acid concentrations also the Impurities are largely co-extracted, in order to produce pure niobium compounds to come, extracting several times is required.

This method of extraction is said to be essential according to the invention be simplified; namely through a combination of procedural steps, which are partly known and partly the subject of not previously known proposals, in particular the use of strong acid concentrations and multiple extraction are avoided will. For this purpose, it is proposed according to the invention, the largely tantalum-free aqueous niobium solution in which the niobium is present as halide, in itself, more known Way to add alkali metal hydroxide, alkali metal carbonate and / or ammonia. Through this an oxide hydrate mixture is brought to precipitation, which niobium hydroxide and the Contains hydroxides of the accompanying elements. In addition, the precipitate contains the, if applicable existing phosphorus and other impurities such as sulfur, silicon and the like. The precipitate is separated from the solution by filtration or decantation, dried and / or lightly annealed. The solid intermediate thus obtained is treated with ketone containing hydrofluoric acid. This can be done by, for example the oxide and / or oxide hydrate mixture is placed in a column through which hydrofluoric acid containing ketone passes through. The ketone emerging from the column contains the Niobium, while the impurities remain as a solid residue.

But it can also contain the solid oxide mixture in hydrofluoric acid Ketone. It is also possible within the meaning of the invention, the solid To suspend oxide hydrate mixture in ketone and the suspension at least as much Add hydrofluoric acid as necessary to form the fluoride. In all cases the solid fraction which is insoluble in the ketone contains those accompanying the niobium. Impurities Titanium, tungsten, tin, iron. For separating the organic solution containing niobium from the residue it is generally sufficient to decant and remove the residue from the Filter off residual solution. The filtrate is decanted with the organic phase united. The organic phase separated from the residue in this way becomes the niobium obtained as a hydrate of oxide by adding alkali metal hydroxide in a manner known per se, Alkalicarbona.t or ammonia is added. But it is also possible, advantageously precipitate a potassium niobium fluoride by following a not previously known proposal Potassium salts, in particular potassium bifluaride, are added to the solution. Through this In addition, the potassium niobium fluoride precipitates in the pure state and is easy to filter.

The method is carried out according to the invention using an exemplary embodiment explained in more detail: 1.15 m3 of hydrofluoric acid-containing tantalum-niobium solution, which is about 60 g / 1 Tantalum and about 57 g / 1 niobium was obtained by dissolving a tantalum and niobium containing precursor obtained. This solution became twelve in the cycle Approaches the Tanta.l with methyl isobutyl ketone in a known manner extracted. The resulting small amounts of tantalum and the impurities titanium, Aqueous niobium solution containing tungsten, tin, iron, phosphorus, manganese was with 350 kg of soda and 250 kg of ammonium hydroxide are added. The 471 kg precipitated as a result Oxide hydrates were dried at 130 °. They contained 17.011 / o Nb2 05 1.6% Taz 05 13.3% Ti 02 2.0 1 / o W 03 0.611 / o sn02 10.311 / o Fe203 In thirteen batches now 35 kg each of this Oxydhydratgemisches in 150 l of methyl isobutyl ketone entered, to which 251 hydrofluoric acid (701 / o) had previously been added. After an hour vigorous stirring and allowing to settle, the niobium-containing ketone phase was drawn off, the residue is placed on a suction filter and filtered off. The ketone phase became by adding. solid potassium bifluoride potassium niobium fluoride precipitated, which is immediately settled in the solution. The remaining ketone was withdrawn and used for next extraction used. The crude potassium niobium fluoride was filtered off. It contained in the dried state: 40.0% Nb2 Ob 1.011 / o Tat 05 0.511 / o Ti 02 traces w03 traces Fe., 03 tracks Mn, 04

Claims (1)

PATENT CLAIM: Process for the production of pure niobium compounds from tantalum-free or low-tantalum, through titanium, tin, tungsten, iron, phosphorus and the like. Like. Contaminated niobium solutions, characterized in that the solution in itself known way with alkali hydroxide, alkali carbonate and / or ammonia for precipitation a contaminated Oxydhydrate is added, whereupon from the filtered off, dried or annealed residue the niobium as pure niobium compounds with hydrofluoric acid Dissolved ketone, separated from the residue and worked up in any way will. Considered publications: "Angewandte Chemie", Issue 13, July 7, 1955, P. 135.