Method for preparing vanadium-and-iron enriched material by using vanadium enriched steel slags

Abstract

The invention relates to a method for preparing a vanadium-and-iron enriched material by using vanadium enriched steel slags. The method comprises the steps that (1), the vanadium enriched steel slagsare pulverized and leached by using an ammonium chloride solution to obtain primary leaching slags through filtering separation; (2), the primary leaching slags are washed and leached by using an organic acid solution, and secondary leaching solution is obtained through filtering separation; (3), the secondary leaching solution is mixed with a hydrogen peroxide solution, primary hydrolysis is conducted after the pH value is adjusted, and primary hydrolysate is obtained after filtering separation; (4), secondary hydrolysis is conducted on the primary hydrolysate after pH is adjusted, and secondary hydrolysate is obtained after filtering separation is conducted; (5), vanadium condensation is conducted after the pH value of the secondary hydrolysate is adjusted, and solid-phase drying is conducted after filtering; or the secondary hydrolysate is heated, evaporated and crystallized. The method has the advantages that the process is short, better effects of saving energy and environment protecting are achieved, the added value of the product is high, the economical benefit is high, and the recovery rate of the vanadium is greatly improved.

Description

technical field [0001] The invention relates to the technical field of vanadium chemical metallurgy, in particular to a method for preparing vanadium-rich iron-rich material by using vanadium-containing steel slag. Background technique [0002] At present, there are two main production technologies of vanadium components in the world. One is to smelt vanadium-titanium magnetite into vanadium-containing molten iron in a blast furnace or an electric furnace, and then oxidize and blow it in a converter to obtain vanadium slag, semi-steel, and vanadium slag. The vanadium is extracted by sodium to produce vanadium pentoxide, and the semi-steel is oxidized and blown in the converter to obtain steel and vanadium-containing steel slag; the process is lengthy and the recovery rate of vanadium is low. It is calculated that this process can only be recovered from vanadium-containing iron water 56% vanadium, and vanadium extraction by sodium will not only consume a large amount of sodiu...

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Problems solved by technology

[0003] China discharges nearly one million tons of vanadium-containing steel slag every year, which not only pollutes the environment, but also causes the loss of valuable element vanadium. At present, there are two main methods for extracting vanadium from vanadium-containing steel slag, one is to carry out pyrometallurgy of vanadium-containing steel slag, High-vanadium slag is smelted, and vanadium is further extracted. The second is to directly extract vanadium from vanadium-containing steel slag as a raw material, which generally requires a hydrometallurgical process; pyrometallurgy includes steel slag return sintering method and steel slag submerged arc furnace reduction smelting method; The steel slag return sintering method adds vanadium-containing steel slag to the sintered ore as a flux and enters the blast furnace for smelting, vanadium is enriched in molten iron, so that the molten iron contains 2-3% vanadium, and then blows to obtain high-grade (V 2 o 5 30-40%) of vanadium slag, in order to produce V 2 o 5 or ferro-vanadium alloy; this method can utilize existing equipment to recover vanadium, and at the same time can also recover iron, manganese, etc., reducing iron-steel ratio and energy consumption; but this method is prone to cyclic enrichment of phosphorus in molten iron, which aggravates the dephosphorization of steelmaking In addition, the steel slag has many impurities and the effective calcium oxide content is relatively low, which will reduce the grade of sinter and increase the energy consumption of the ironmaking process, so it is not suitable to mix in a large amount; the reduction smelting method of steel slag submerged arc furnace uses submerged arc furnace to forge Burning, by controlling the reducing atmosphere in the furnace, the vanadium in the steel slag is reduced and enriched into molten iron to obtain high-vanadium pig iron, and then in the induction furnace, the vanadium in the high-vanadium pig iron is oxidized into slag by controlling the oxidizing atmosphere in the furnace, High vanadium slag can be obtained; but V in steel slag 2 o 5 While being reduced, the P in steel slag 2 o 5 It also needs to be reduced and enters the pig iron, resulting in a higher P content in the pig iron. Using this vanadium-containing pig iron with high phosphorus content to extract vanadium, the P in the vanadium slag and semi-steel is also higher; the vanadium-containing steel slag directly extracts vanadium The methods include sodium roasting, blank roasting, calcification roasting, calcium-reducing roasting and direct acid leaching and other processes; sodium roasting uses salt or soda as an additive to convert multivalent vanadium into water-soluble pentavalent vanadium sodium through roasting salt, and then soak the sodium roasted product directly in water to obtain a vanadium-containing leaching solution, and then add ammonium salt to obtain ammonium metavanadate precipitation, and roast to obtain crude V 2 o 5 , and then through alkali dissolution, impurity removal and secondary vanadium precipitation with ammonium salt to obtain ammonium metavanadate, after roasting, V with a purity greater than 98% can be obtained 2 o 5 , this process consumes a lot of sodium salt and is not suitable for processing 2 o 5 Converter vanadium-containing steel slag with low and high CaO; blank roasting is without any additives, and the low-priced vanadium is directly converted into acid-soluble V by oxygen in the air at high temperature. 2 o 5 , and then use sulfuric acid to leach the vanadium in the calcined sand; the roasting conversion rate and heat utilization efficiency of this method are low, and secondly, the acid consumption of this method is high, the impurities in the acid leaching solution are more, and the ammonium salt consumption is also high during vanadium precipitation, so This method is not suitable for large-scale production; calcification roasting is to add a flux such as lime to the vanadium-containing steel slag and roast it. Because of the calcification roasting, vanadium is converted into calcium vanadate which is insoluble in water, which is beneficial to the weak acid leaching of vanadium; The material has certain selectivity, and there are problems such as low conversion rate and high cost for general steel slag, so it is not suitable for large-scale production; Calcium-reducing roasting is to combine vanadium-containing steel slag with Na 3 PO 4 , Na 2 CO 3 Mixed roasting, Na 3 PO 4 Combines with CaO to form Ca 3 (PO4) 2 , vanadium and sodium form water-soluble Na 3 VO 4 , and then soaked in water to dissolve vanadium; but this method has a large proportion of phosphate and high cost, and has not yet been industrialized, and only stays in the laboratory research stage; direct acid leaching refers to complete wet extraction without roasting process. Vanadium, but due to the high content of CaO in steel slag, the acid consumption is large and the cost is high; the acid leaching process needs to be carried out in a strong acid solution, and the leachate obtained has more impurities, which is difficult to carry out subsequent separation

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