System and method for producing high-purity vanadium pentoxide through clean chlorination of vanadium residue

Abstract

The invention discloses a system and a method for producing high-purity vanadium pentoxide through clean chlorination of vanadium residue. According to the present invention, through fluidized bed oxidative granulation treatment, the mineral phase reforming and the mineral particle growth of the vanadium residue are achieved; the vanadium in the vanadium residue is converted into gaseous vanadiumoxytrichloride through selective chlorination, and most of impurities such as chromium, iron, calcium, phosphorus, manganese, titanium, silicon and the like are remained in the chlorinated residue soas to achieve effective separation of other impurities such as vanadium, chromium and the like; the gaseous vanadium oxytrichloride is sequentially subjected to dust removal, leaching, settlement, rectification purification, catalytic oxidation and other processes to prepare the high-purity vanadium pentoxide; the chlorinated residue is subjected to gas phase hydrolysis dechlorination treatment, and the treated residue returns to ferrochromium smelting; and with the system and the method, the clean comprehensive utilization of vanadium residue is achieved, and the sensible heat of the high temperature flue gas of the chlorination furnace is effectively utilized so as to achieve the purposes of energy saving and consumption reduction.

Description

technical field [0001] The invention belongs to the fields of metallurgy and chemical industry, in particular to a system and method for producing high-purity vanadium pentoxide by clean chlorination of 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. [0003] Vanadium-titanium magne...

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, the vanadium slag in this process directly enters the chlorination furnace without pretreatment, which will reduce the selectivity of vanadium chlorination, convert a large number of harmful elements into chlorides, and greatly increase the cost of subsequent distillation purification and chlorination residue treatment

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

Moreover, the heat balance of the chlorination furnace, the sensible heat of the high-temperature chlorination flue gas and the chlorination residue are not well utilized.

[0005] In summary, the existing chlorination vanadium extraction process presents significant technical superiority, but there are still many outstanding problems: (1) the chlorination selectivity is poor, and when the vanadium element is chlorinated in the vanadium resource, it will cause The chlorination of other iron, titanium, chromium, calcium, phosphorus, and silicon leads to difficulties in rectification purification and chlorination residue treatment; (2) chlorination and roasting of vanadium resources is a strong exothermic process, and the heat generated by chlorination In addition to satisfying the preheating of solid and gas reaction materials, heat exchange and cooling are still required

Distillation and wastewater crystallization require a lot of energy

The energy of the preceding and following processes cannot be effectively coordinated and utilized, which will greatly increase energy consumption and increase production costs; (3) the preparation of industrial vanadium products vanadium pentoxide by vanadium chloride (vanadium oxychloride) lacks an efficient and clean technical route. The hydrochloric acid solution has high solubility, and the direct liquid-phase hydrolysis will cause the recovery rate of vanadium to be too low. Although the precipitation with ammonium salt can improve the precipitation rate of vanadium, it will produce a large amount of ammonia-nitrogen waste water; although the process of gas-phase hydrolysis avoids the production of Ammonia nitrogen will separate water, but it will bring a large amount of vanadium-containing hydrochloric acid, and the environmental problems are prominent; (4) the existing vanadium extraction process by chloride is mainly aimed at ordinary vanadium slag, and is not practical for chromium-containing vanadium slag

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