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

Abstract

The present invention discloses a system and a method for producing high-purity vanadium pentoxide through clean chlorination of vanadium resources. According to the present invention, vanadium resources are subjected to granulation, oxidation, crushing, screening and other pretreatment processes, the pre-treated vanadium resources enter a chlorination furnace and are selectively chlorinated, thevanadium in the vanadium resources is converted into gaseous vanadium oxytrichloride, and most of impurities such as iron, chromium, calcium, phosphorus, manganese, titanium, silicon and the like in the vanadium resources are retained in the chlorinated residue so as to achieve the effective separation of vanadium and other impurities; the gaseous vanadium oxytrichloride is sequentially subjectedto dust removal, leaching, settlement, rectification purification, catalytic oxidation and other processes to prepare the high-purity vanadium pentoxide; the chlorinated residue is sequentially subjected to waste heat recovery, water washing dechlorination, settlement separation, filtering washing and other processes to obtain filter residue and a washing liquid, the filter residue returns to ironsmelting, and the washing liquid is subjected to evaporation crystallization to obtain a chlorine salt; and with the system and the method, the clean comprehensive utilization of vanadium resources is achieved while the sensible heat of the high temperature flue gas of the chlorination furnace and the high temperature chlorination residue is effectively utilized so as to achieve purposes of energy saving and consumption reduction.

Description

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

AI Technical Summary

Problems solved by technology

The process mainly has the following outstanding problems: (1) lengthy process, high energy consumption and high production cost; (2) low vanadium recovery rate, less than 80% from vanadium slag to vanadium oxide products; (3) vanadium extraction residue Difficult to deal with, 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 process of leaching and vanadium precipitation produces a large amount of ammonia nitrogen wastewater containing various harmful metal ions and sodium sulfate. 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 main outstanding problems in the existing vanadium extraction technology by chlorination include: (1) the selectivity of chlorination is poor, when vanadium element in vanadium resources is chlorinated, it will lead to other iron, chromium, calcium, phosphorus, titanium 1. Chlorination of silicon, resulting in difficulties in rectification and purification and treatment of chlorination residues; (2) Chlorination and roasting of vanadium resources is a strong exothermic process, and the heat generated by chlorination reaction can not only meet the preheating of solid and gas reaction materials , still needs heat exchange and cooling treatment

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 wastewater, but it will bring a large amount of vanadium-containing hydrochloric acid, and the environmental problems are prominent; etc.

These problems are all important reasons why the existing vanadium resource chlorination vanadium extraction process cannot be applied on a large scale

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