System and method for high-value comprehensive utilization of high-chromium vanadium slag

Abstract

The invention discloses a system and method for high-value comprehensive utilization of a high-chromium vanadium slag. Vanadium, chromium and iron in the high-chromium vanadium slag are converted through selective chlorination by a circulating fluidized bed to corresponding gaseous chlorides, and most impurities such as manganese, titanium, and silicon are remained in the chlorinated residue, so that valuable elements are separated from other impurities. The gaseous chlorides separates crude chromium trichloride by high temperature dust collection, separates crude ferric chloride by medium temperature dust collection, and separates crude vanadium oxychloride from low temperature elution. The crude chromium trichloride is dissolved and stirred to obtain an aqueous solution to recover the chromium salt; the crude ferric chloride and chlorinated residue are hydrolyzed and dechlorinated by high temperature to obtain an oxidized slag for iron production; and the crude vanadium oxychloride vanadium is subjected to sedimented purification, rectification and refinement, and catalytic oxidation to obtain high-purity vanadium pentoxide powder. By means of the system and the method, the high-value comprehensive utilization of the high-chromium vanadium slag is achieved, and the chromium chloride solution and high purity vanadium pentoxide powder are produced by the method of one-step of chlorination with multi-step recovery.

Description

technical field [0001] The invention belongs to the fields of metallurgy and chemical industry, and particularly relates to a system and method for high-value comprehensive utilization of high-chromium vanadium slag. Background technique [0002] Vanadium pentoxide is an important metallurgical chemical material, which has been mainly used as an additive to iron-based alloys to produce alloy steel. In recent years, with the rapid development of industrial technology, the application proportion of vanadium pentoxide in aerospace alloys, energy storage materials, petrochemical catalysts and other fields has gradually increased. In particular, the rapid development of energy storage materials (all-vanadium redox flow battery electrolyte, lithium vanadate cathode material) and high-performance aerospace alloys (vanadium-aluminum series, vanadium-titanium alloy) industry has produced high-quality and high-purity vanadium pentoxide. Huge demand. Chromium trichloride is also an i...

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] To sum up, the existing technology for high-chromium vanadium slag still cannot achieve efficient treatment, and there is also a lack of high-value utilization of vanadium and chromium technology

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 technology can realize high-value utilization of vanadium and chromium at the same time

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