Method for recycling vanadium from vanadium-containing steel slag

Abstract

The invention discloses a method for recycling vanadium from vanadium-containing steel slag, which comprises the following steps, (1) reaction: the vanadium-containing steel slag is reacted in NaOH solution with the mass concentration being 10%-50%, and reaction slurry is obtained; the mass ratio of the NaOH solution to the steel slag is (3:1)-(10:1), the reaction temperature is 180 DEG C to 350 DEG C, the reaction time is 0.5-10h, and the reaction pressure is 0.3-12MPa; (2) dilution: the reaction slurry is diluted through a diluent so as to enable the concentration of sodium hydroxide in the slurry to be 100-400g / L, and mixed slurry is obtained; (3) solid-liquid separation: solid-liquid separation is carried out to the mixed slurry, and calcium-rich tailings and dissolved-out liquid are obtained; (4) impurity removal: a desiliconization agent is added into the dissolved-out liquid to perform impurity removal, then solid-liquid separation is performed, and impurity-removed liquid and silicon-containing slag are obtained; and (5) crystallizing: the impurity-removed liquid is cooled and crystallized, and a sodium vanadate product is obtained. The method effectively reduces production cost of vanadium, and the vanadium leaching rate can be 99%.

Description

technical field [0001] The invention belongs to the field of vanadium-containing chromium slag hydrometallurgy and vanadium chemical industry, in particular to a method for recovering vanadium from vanadium-containing steel slag. Background technique [0002] Vanadium-containing steel slag is a by-product of smelting vanadium-titanium magnetite, which is formed by vanadium-containing molten iron steelmaking. 2 o 5 In the 2% to 10% steel slag (compared with vanadium slag, its calcium content is larger), there are two ways to produce it. One is that the vanadium remaining in the semi-steel is oxidized into the slag after steelmaking, and the other is that Vanadium-containing steel slag is obtained by direct steelmaking of molten iron without blowing vanadium slag. Vanadium-containing steel slag has the following characteristics: (1) high CaO and iron content, perfect crystallization, dense texture, and poor dissociation degree; (2) complex composition and large fluctuation;...

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Problems solved by technology

However, this method only stays in the stage of laboratory research, and the proportion of phosphate is large, the cost is high, and there is no industrial promotion at present.

Direct acid leaching refers to the complete wet extraction of vanadium without roasting process. However, due to the high content of CaO in steel slag, the acid consumption is large and the cost is high; Difficult for subsequent separation

[0004] Chinese patent CN102071321A proposes a method for extracting vanadium and chromium from vanadium-containing steel slag with a high-basic potassium hydroxide medium. This method does not require high-temperature roasting, and the reaction temperature is reduced to 160-240°C. Vanadium and chromium are extracted by wet method. effectively prevents C 12 , HCl, SO 2 , dust and other air pollutants, and reduce the amount of waste water production and discharge; the disadvantage is that the KOH medium is expensive, and the mass ratio of KOH to steel slag is 3:1 to 5:1, and the reaction alkali concentration is 60% to 90%. The loss of KOH medium is more, resulting in higher production costs and lower product benefits

[0005] Chinese patent CN102094123A proposes a method for extracting vanadium from vanadium-containing steel slag with a high-concentration sodium hydroxide medium. The reaction temperature of this method is 180-240 °C, and the vanadium is extracted by wet method without waste gas and dust pollution in the process; the disadvantage is The alkali concentration is too high, and the alkalinity is 65% to 90%, which will lead to higher heat required for evaporation and concentration during medium recycling, resulting in higher production costs, and the residual V in the final slag is higher, and the leaching rate is not high. , the V content in the final slag is 0.3%~0.5%

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