A method for clean and efficient recovery of vanadium by sodium-free roasting of vanadium slag

Abstract

The invention discloses a method for cleanly and efficiently recovering vanadium from vanadium slag by employing sodium-free roasting. The method comprises the following steps: (1) mixing the vanadium slag with 0-30% of additive, and then carrying out oxidizing roasting at 400-1300 DEG C, so as to obtain roasted clinker; (2) discharging the roasted clinker from a furnace and then directly feeding into a section of leaching lye to cool and leach, so as to obtain a section of alkali leaching liquid and primary slag; (3) separating a vanadium-containing solution by adding calcium, so as to obtain a calcium orthovanadate product, or feeding to the vanadium-containing solution into a traditional acid ammonium salt vanadium process to obtain an ammonium vanadate product; (4) feeding the primary slag into two sections of alkali leaching processes, so as to obtain two sections of alkali leaching liquid and secondary slag, and cooling and crystallizing the two sections of alkali leaching liquid, so as to obtain vanadate crystals; (5) converting the vanadate into a calcium orthovanadate product by calcification. By adopting the method disclosed by the invention, a sodium-free roasting technology is adopted, so that the problems of ring formation of a rotary kiln, environmental pollution and ammonia-nitrogen wastewater in the traditional sodium roasting process are avoided; the method has the characteristics of being high-efficiency in processes and short in technological process; the recovery rate of the vanadium is higher than 95%.

Description

technical field [0001] The invention belongs to the technical field of vanadium chemical metallurgy, in particular to a method for cleanly and efficiently recovering vanadium by roasting vanadium slag without sodium. Background technique [0002] Enterprises that use vanadium-titanium magnetite as raw materials to produce iron and vanadium products currently use the traditional vanadium slag sodium roasting process to extract vanadium from vanadium slag, such as my country's Panzhihua Iron and Steel Corporation, Chenggang Iron and Steel Co., Ltd. in South Africa, and New Zealand Iron and Steel Co., Ltd. company etc. The basic principle of sodium roasting process is based on Na 2 CO 3 As an additive, low-valence vanadium is converted into water-soluble pentavalent vanadium sodium salt through high-temperature sodium roasting (750-850°C), and then the sodium roasted product is directly immersed in water to obtain a vanadium-containing leaching solution. Ammonium polyvanadate...

AI Technical Summary

Problems solved by technology

The recovery rate of vanadium in the sodium roasting process is low, the recovery rate of vanadium in a single roasting is about 70%, and the recovery rate of vanadium after multiple roasting is only 85%; the roasting temperature is high (750-850 ° C), and multiple roasting is required , high energy consumption; in the roasting process will produce harmful HC1, C1 2 and other corrosive gases, polluting the environment

[0003] Chinese patent CN1082617A proposes to treat the high-temperature vanadium slag obtained by blowing by blowing oxygen directly at 900-1300°C to promote the oxidation of low-valent vanadium in the slag to vanadium pentoxide. , The vanadium in the slag is leached under oxygen partial pressure. This method does not need to be roasted at high temperature again after the vanadium slag is cooled, the energy consumption is greatly reduced, and the environmental pollution caused by sodium roasting is avoided, but there is metal iron that cannot be recovered, and the recovery of vanadium low rate problem

However, the roasting temperature of calcification roasting is still very high (600-950°C), and the recovery rate of vanadium is very low, so the problem of acidic wastewater cannot be avoided.

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