Method for extracting sodium metavanadate from vanadium extraction leaching solution

Abstract

The invention discloses a method for extracting sodium metavanadate from a vanadium extraction leaching solution, comprising the following steps of: adjusting the pH value of the sodium-ionized vanadium extraction leaching solution to 4-4.5 by using inorganic acid, then heating the solution to the temperature of 75-85 DEG C, then adding a soluble ammonium salt into the solution according to the mass ratio of NH4+:V=1.5-2, fully and uniformly stirring, and obtaining sodium polyvanadate containing ammonium after the reaction is finished; putting the obtained sodium polyvanadate containing ammonium into a sealed reactor, adding sodium hydroxide according to the mol ratio of Na:V=0.8-0.9, stirring at the temperature ranging from 90 DEG C to the boiling temperature till the solution starts to precipitate a white or light yellow solid, cooling the solution to the room temperature under the condition of stirring, filtering and drying to obtain a sodium metavanadate solid.

Description

technical field [0001] The invention relates to a method for preparing sodium metavanadate from vanadium extraction leaching solution. Background technique [0002] Sodium metavanadate is widely used in the chemical industry. It can be used as chemical reagent, catalyst, drier, mordant, manufacture ammonium vanadate and potassium metavanadate, and can also be used in medical photography, plant inoculation and corrosion inhibitor, etc. . [0003] At present, the preparation of sodium metavanadate at home and abroad is mainly extracted from the vanadium-containing sodium roasting leaching solution. There are three main methods: one method is to use the vanadium extraction leaching solution to evaporate, concentrate and crystallize; the second is to use the vanadium extraction leaching solution to precipitate more Ammonium vanadate, and then dissolve with sodium hydroxide solution; the third is to dissolve V with sodium hydroxide solution 2 o 5 Law. [0004] Evaporation con...

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Problems solved by technology

[0004] Evaporation concentration and crystallization method is to evaporate and concentrate the vanadium extraction leachate obtained by leaching to obtain solid sodium metavanadate after removing impurities. This method is simple in process and easy to operate, but the composition of the leachate is complex and the removal of impurities is not complete, resulting in low product purity. High, difficult to be widely used

The ammonium polyvanadate solid alkali dissolution method is to add ammonium salt precipitation to the vanadium-containing leaching solution to obtain ammonium polyvanadate. The precipitation temperature is required to be around 90-95°C, and then add sodium hydroxide solid to dissolve to obtain sodium metavanadate solid. The shortcoming of a kind of method is that the pH value is adjusted to 2-2.5 in the precipitation ammonium polyvanadate process, consumes a large amount of acid, needs to add the sodium hydroxide of equal molar quantity with vanadium then in the process of adding sodium hydroxide back to dissolve, and alkali consumption Large, so the production cost is higher, the reaction principle is (NH 4 ) 2 V 6 o 16 +6NaOH=6NaVO 3 +2NH 3 ↑+4H 2 O: Ammonium polyvanadate usually presents a flocculent or polycrystalline polymer, and contains impurities such as sodium sulfate that are not easy to wash, resulting in low product purity

The third method is to dissolve V with sodium hydroxide solution 2 o 5 Method, heating and fully reacting to obtain sodium metavanadate, this method is easy to operate, the product has high purity, and solves the generation of polluted waste gas ammonia. This method is the most widely used method at present, but this method has great impact on V 2 o 5 Higher purity requirements, V 2 o 5 The price is more expensive, so the production cost is high, and the reaction principle is V 2 o 5 +2NaOH=2NaVO 3 +H 2 o

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