System and method for high-efficiency extraction of vanadium from vanadium slag through chlorination

Abstract

The invention specifically discloses a system and method for high-efficiency extraction of vanadium from vanadium slag through chlorination, belonging to the fields of chemical engineering and metallurgy. By means of heat exchange between chlorination gas and chlorination flue gas, the chlorination gas is preheated; a proper amount of air is added to allow a part of coke powder to combust, thus providing a balanced supply of heat during the process of chlorination; by means of high-temperature fluidization oxidation of chlorinated slag, the chlorinated slag is treated in a comprehensive manner, and the chlorine gas is recycled; furthermore, by means of vapor-phase hydrolysis of the chlorination product vanadium oxytrichloride, a powdered vanadium pentoxide product and a hydrochloric acid byproduct are obtained; so the efficiency of chlorination is improved, the consumption of chlorine gas is reduced, the harm of the chlorinated slag is eliminated, and the problem of ammonia-nitrogen pollution caused by conventional ammonium salt precipitation is prevented. The system and method provided by the invention are applicable to extraction of vanadium from vanadium slag containing 10 to 28 wt% of V2O5 through chlorination and have the advantages of high efficiency, low energy consumption, no pollution, good economic performance, etc.

Description

technical field [0001] The invention belongs to the fields of chemical industry and metallurgy, and particularly relates to a system and method for efficiently chlorinating vanadium slag and extracting vanadium. Background technique [0002] Vanadium-titanium magnetite is an important symbiotic resource of vanadium, titanium and iron. Titanium is enriched in smelting slag by reduction smelting, vanadium is reduced to molten iron and then further blown to obtain V-containing 2 o 5 10wt%-28wt% vanadium slag, so that the separation and utilization of vanadium, titanium and iron resources in minerals can be effectively realized. At present, in the industry, the extraction of vanadium in vanadium slag is mainly achieved through the preparation of vanadium oxide products through sodium roasting-leaching-precipitation-calcination-decomposition, and there are the following outstanding problems: (1) lengthy process, high energy consumption, and high production costs; (2) ) The van...

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Problems solved by technology

At present, in the industry, the extraction of vanadium in vanadium slag is mainly achieved through the preparation of vanadium oxide products through sodium roasting-leaching-precipitation-calcination-decomposition, and there are the following outstanding problems: (1) lengthy process, high energy consumption, and high production costs; (2) ) The vanadium recovery rate is low, and the recovery rate from vanadium slag to vanadium oxide products is less than 80%; (3) Environmental problems are prominent, and the introduction of a large amount of sodium in the sodium roasting process makes the comprehensive utilization of extraction tailings difficult, and the leaching-precipitation process produces a large amount of Ammonia nitrogen wastewater containing a variety of harmful metal ions and sodium sulfate has a serious impact on the ecological environment

[0005] The main outstanding problems in the existing chlorination vanadium extraction technology include: (1) The chlorination and roasting of vanadium slag is a strong exothermic process, and the heat generated by the chlorination reaction needs to be passed through The chlorination temperature can only be stabilized by removing the heat from the furnace wall, so solids and gases usually enter the reactor at near room temperature, and can only participate in the reaction after being preheated by the heat generated by the chlorination reaction, which makes the local reaction efficiency of the chlorination reactor too low (2) Due to the need to remove the heat produced by the chlorination reaction through a large amount of heat dissipation to maintain the operating temperature, the operating conditions and environmental climate changes are likely to cause fluctuations in the chlorination temperature, resulting in a reduction in the selectivity and efficiency of chlorination. Reasonable heat needs to be used Balanced supply and temperature control methods; (3) For the chlorine-containing tailings produced by chlorination and roasting of vanadium slag and the impurity chlorides produced by the separation and removal of chlorides, effective comprehensive treatment methods cannot be provided, which can easily cause environmental pollution; ( 4) The preparation of industrial vanadium products vanadium pentoxide by vanadium chloride (vanadium oxychloride) lacks an efficient and clean technical route. Because vanadium has a high solubility in hydrochloric acid solution, direct hydrolysis will cause the recovery rate of vanadium to be too low. Although the use of ammonium salt precipitation can increase the precipitation rate of vanadium, it will produce a large amount of ammonia nitrogen wastewater, and the environmental problems are prominent; etc.

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

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