A system and method for producing high-purity energy storage materials for flow batteries from high-chromium vanadium slag

Abstract

The invention discloses a system and a method for producing a high-purity energy storage material for liquid flow batteries by using high chromium type vanadium residue. According to the present invention, through selective chlorination in a circulating fluidized bed, vanadium, chromium and iron in high chromium vanadium residue are converted into corresponding gaseous chlorides, and most of impurities such as manganese, titanium, silicon and the like in the vanadium residue are remained in the chlorinated residue so as to separate the valuable elements from other impurities; the gaseous chloride is subjected to high temperature dust collection to separate crude chromium trichloride, is subjected to medium temperature dust collection to separate crude ferric chloride, and is subjected to low temperature leaching to separate crude vanadium oxytrichloride; the crude chromium trichloride is subjected to volatilization purification to obtain high-purity chromium trichloride; the crude ferric chloride is subjected to volatilization purification to obtain high-purity ferric chloride; the crude vanadium oxytrichloride is subjected to rectification purification and catalytic oxidation to obtain high-purity vanadium pentoxide powder; and with the system and the method, the high-value comprehensive utilization of the high chromium type vanadium residue is achieved, and the high-purity energy storage material for liquid flow batteries is obtained through the one-step chlorination multi-stage recovery method.

Description

technical field [0001] The invention belongs to the fields of energy and chemical industry, and in particular relates to a system and method for producing high-purity energy storage materials for liquid flow batteries from high-chromium vanadium slag. Background technique [0002] Flow battery is a safe and reliable large-scale energy storage system, which has the advantages of high energy efficiency, easy system integration and scale-up. Among them, all-vanadium redox flow battery and iron / chromium redox flow battery are two battery systems with rapid development, and both have achieved battery modules above 10kW. All-vanadium redox flow batteries use vanadium pentoxide sulfuric acid solution as electrolyte; iron / chromium redox flow batteries use ferric chloride and chromium chloride hydrochloric acid solution as electrolyte; higher electrolyte purity can significantly reduce battery electrode Side reactions, so as to obtain higher energy conversion efficiency. With the r...

AI Technical Summary

Problems solved by technology

If the high-chromium vanadium slag is treated by the process of "sodium roasting-leaching-vanadium precipitation-calcination decomposition", there are two main problems as follows: (1) The recovery rate of vanadium is low

In high chromium vanadium slag, chromium spinel and vanadium spinel are in solid solution together, and chromium spinel is an ore that is more difficult to oxidize and decompose than vanadium spinel, and the ordinary vanadium slag extraction method is used , the vanadium recovery rate is very low

(2) The vanadium-chromium solution mixes with each other, making it difficult to separate

Under such conditions, vanadium and chromium enter the liquid phase at the same time, making it difficult to separate effectively, and produce a large amount of chromium-containing wastewater, polluting the environment

And the sodium roasting process itself also has the following outstanding problems: (1) the flow process is lengthy, the energy consumption is high, and the production cost is high; (2) the vanadium recovery rate is low, and the recovery rate from vanadium slag to vanadium oxide products is less than 80%; (3) ) The vanadium extraction residue is difficult to handle, and sodium roasting introduces a large amount of sodium salt, which limits the residue directly returning to the blast furnace for ironmaking; (4) Environmental problems are prominent, and the leaching-vanadium precipitation process produces a large amount of harmful metal ions and sodium sulfate. Ammonia nitrogen wastewater has a serious impact on the ecological environment

However, this patent does not involve high-chromium vanadium slag, nor does it provide a separation method for ferrochromium and vanadium

The chlorination flue gas volatilized from the chlorination furnace is directly exchanged for heat without dust removal treatment, which will cause pipeline blockage and seriously affect production

The gas phase hydrolysis process will produce a large amount of vanadium-containing hydrochloric acid, which will increase the cost of environmental protection

At the same time, the sensible heat of high-temperature chlorination flue gas is not well utilized.

[0005] In summary, the existing process for high-chromium vanadium slag still cannot achieve efficient treatment, and there is also a lack of simultaneous recovery of vanadium, chromium, and iron in it to produce high-purity energy storage materials

Existing chlorination process presents significant technical superiority, but there are still some prominent problems: (1) the preparation of high-purity vanadium pentoxide by vanadium chloride (vanadyl trichloride) lacks an efficient and clean technical route, Due to the high solubility of vanadium in hydrochloric acid solution, direct liquid-phase hydrolysis will cause the recovery rate of vanadium to be too low, and the use of ammonium salt precipitation can improve the precipitation rate of vanadium, but it will produce a large amount of ammonia-nitrogen waste water; the process of gas-phase hydrolysis Although avoiding the production of ammonia nitrogen and water separation, it will bring a large amount of vanadium-containing hydrochloric acid, and the environmental problems are prominent; (2) the existing vanadium chloride extraction process is mainly aimed at ordinary vanadium slag, and there is no efficient chlorination method for high-chromium vanadium slag extraction technique

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