System and method for preparing high-purity vanadium electrolytic solution through efficient clean chlorination method

Abstract

The invention belongs to the fields of metallurgy and chemical industry, and specifically discloses a system and a method for preparing a high-purity vanadium electrolytic solution through an efficient clean chlorination method, wherein high-purity and low-valence vanadium oxide powder is prepared by using a process comprising chlorination, dust removal leaching, purification, catalytic oxidation,fluidization reduction and fluidized bed dissolution, the equivalent average valence of vanadium can be any one value selected from 3.0-4.0, and the low-valence vanadium oxide is subjected to low-temperature dissolving by adding ultrapure water and pure sulfuric acid to a liquid-solid fluidized bed to obtain the high-purity vanadium electrolytic solution capable of being directly used for all-vanadium redox flow batteries. According to the present invention, the chlorine gas is regenerated by introducing clean oxygen-rich air into the catalytic oxidation fluidized bed, such that the chlorinegas circulation is achieved, and the production cost is reduced; the hydrogen chloride in the catalytic oxidation tail gas is recovered by the hydrochloric acid condensation absorption tower, such that the generation of vanadium-containing hydrochloric acid is eliminated, and the environmental protection cost is substantially reduced; and the system and the method have advantages of strong raw material adaptability, low production energy consumption, low operation cost, stable product quality and the like, and are suitable for the large-scale industrial production of high-purity vanadium electrolytic solutions.

Description

technical field [0001] The invention belongs to the fields of chemical industry and energy, and relates to a system and method for preparing high-purity vanadium electrolyte by an efficient and clean chlorination method. Background technique [0002] Vanadium redox flow battery (VRFB) is a large-scale energy storage device with good commercial application prospects. After more than 30 years of development, VRFB technology has been gradually improved, and industrial demonstrations of tens of megawatts have been realized. The theoretical cycle number of all-vanadium redox flow battery is unlimited, and its service life is considered to be more than 20 years in actual industrial use. In the long-term service process, in order to avoid the occurrence of harmful side reactions, the purity of the vanadium electrolyte is highly required. Within the acceptable range of economic cost, the higher the purity, the better. The level of purity is directly related to the service life of...

AI Technical Summary

Problems solved by technology

This patent has the following deficiencies: (1) carbon chlorination is a violent exothermic process, which needs to transfer heat to the outside of the chlorination furnace; air is blown into the chlorination furnace in this patent, which will cause the furnace temperature to rise and affect Fluidized state; (2) The flue gas dedusting-condensation part is very simple, and the chlorinated flue gas is mixed with a large amount of unreacted dust. A single cyclone separator cannot achieve effective dust removal effect, and the backward movement of dust will block the follow-up pipe Road, bring the hidden danger of stopping production; Simultaneously insufficient vanadium oxychloride condensation will reduce recovery rate greatly, increase production cost; (3) rectifying purification can only separate the metal chloride that differs greatly from the saturated vapor pressure of vanadyl trichloride However, some such as titanium, silicon chloride and vanadyl chloride saturated vapor pressure are close, and it is difficult to obtain high-purity vanadyl chloride by the method of rectification alone; (4) gas phase ammonization-ammonium salt calcination process will produce a large amount of chlorine Ammonium chloride and ammonia-rich tail gas increase environmental protection costs

This patent has the following deficiencies: (1) There are a large amount of impurities such as iron, manganese, chromium, titanium, and aluminum in the vanadium slag, which are converted into chlorides in a large amount during the chlorination process, and a large amount of chlorination tailings pollute the environment and cannot be used economically and efficiently; (2) This patented technology also has the problems of overheating of the chlorination furnace, blockage of pipelines, low recovery rate of vanadyl trichloride, substandard purity of vanadyl trichloride, and inability to handle a large amount of vanadium-containing hydrochloric acid

[0016] CN106257724A discloses the technology of preparing high-purity and low-priced vanadium oxides by reducing ammonium vanadate in a fluidized bed. The main problem is that the reduction tail gas contains a large amount of ammonia and ammonium chloride dust, which seriously pollutes the environment and increases environmental protection costs. Large-scale industrial production; and the latent heat of the reduction tail gas is not utilized, which is not conducive to the reduction of production costs

CN106257725A discloses a technology for preparing high-purity and low-valent vanadium oxides by reducing vanadium-containing materials in a fluidized bed. The disadvantage is that the latent heat of tail gas is not utilized, and the production cost increases

CN106257726A discloses a technology for preparing high-purity and low-valent vanadium oxides by reducing ammonium vanadate in a fluidized bed. The disadvantages are the pollution of ammonia in the reduction tail gas and the utilization of latent heat of the reduction tail gas

CN106257727A discloses a technology for preparing high-purity vanadium oxide by reducing vanadium pentoxide wet material in a fluidized bed. The main deficiency of this patent is that the water content of the vanadium pentoxide filter cake is relatively high, which is not conducive to the transportation of the screw feeder; Moreover, the vanadium pentoxide wet material is directly subject to the high-temperature gas heat exchange from the tail gas burner, which is prone to sintering, resulting in a too wide particle size distribution of the vanadium pentoxide powder, which is not conducive to the reduction operation of the reducing fluidized bed

CN106257728A also discloses a technique for preparing high-purity and low-valence vanadium oxides by reducing vanadium pentoxide powder in a fluidized bed, which also has the problem that the latent heat of the reduction tail gas is not utilized

[0017] In addition, for industrial large-scale application, the existing chlorination method to prepare high-purity electrolyte still has the following six problems: (1) The chlorination of vanadium raw materials is a strong exothermic process, and the heat generated by the chlorination reaction can not only satisfy In addition to the preheating of solid and gaseous reaction materials, there is still a large amount of surplus, which will lead to local overheating of the vanadium material, affecting the fluidization state and the selectivity of chlorination. It is necessary to find an effective way to remove the heat from the fluidized bed; (2) chlorination fume The dedusting and condensing section of the gas is related to the continuity of production and the recovery rate of vanadium trichloride, which requires special devices to be strengthened; (3) rectification / distillation purification can only separate the gas with a large difference in saturated vapor pressure from vanadyl trichloride Metal chlorides, yet some such as titanium, silicon chloride and vanadyl trichloride saturated vapor pressure are close, it is difficult to obtain high-purity vanadyl trichloride by the method of rectification / distillation alone, need to coordinate other effective impurity removal methods; (4 ) preparing vanadium pentoxide by vanadium oxychloride still does not have a clean, efficient and environmentally friendly preparation method

If chlorine gas cannot be recycled and vanadium-containing hydrochloric acid cannot be effectively treated, it will greatly increase production costs and environmental protection costs, making it difficult to achieve large-scale industrialization

(5) The preparation of low-priced vanadium oxides by fluidized bed reduction still faces problems such as material transportation, ammonia treatment in tail gas, and comprehensive utilization of heat in tail gas.

(6) There are deficiencies in the existing vanadium electrolyte preparation method

The low-valent vanadium oxide dissolution method usually adopts the method of stirring the reactor, which has a blind zone of stirring, and the dissolution efficiency is low, and it takes a long time to stir to fully dissolve

Images