Effectively improve the comprehensive utilization rate of stone coal vanadium ore, reduce costs, vanadium leaching rate is the key. In order to improve the leaching rate of vanadium, researchers have done a lot of work, such as sodium roasting-leaching, oxidizing roasting-leaching, calcification roasting-leaching, roasting-leaching, oxygen pressure leaching and direct high acid. Leaching method. Among them, the roasting-leaching method has a large investment. Due to the complicated process and high processing cost, it is not easy to be industrialized. It is even more fatal that due to the complexity of the ore nature, a large amount of exhaust gas is generated during the roasting process, causing the surrounding environment. Severe damage; oxygen pressure leaching method is still in the laboratory stage, the treatment cost is also high, industrialization will take time; direct acid leaching method is currently more advanced technology, but the vanadium in the stone coal vanadium ore The storage state is more complicated. In direct acid leaching, the leaching rate of vanadium is the key to process application. The Zhongcun Vanadium Mine of Shaanxi Wuzhou Mining Company is an adsorbed vanadium ore. It is mainly composed of tetravalent vanadium, which is relatively easy to leach and directly leached with sulfuric acid. The leaching rate can reach 80%. In order to further improve the leaching rate and reduce the cost, we have conducted in-depth research on the ore. By adding a dipping agent, the leaching rate is greatly improved, and the leaching rate can reach over 93%.

First, the nature of the ore

Ore mineral composition in a non-metallic mineral-based, metallic minerals less. Metallic minerals limonite ore most, pyrite, iron, vanadium, iron, vanadium anatase and the like; non-metallic mineral quartz, clay-based, time calcite, graphite, carbon, etc., as minerals apatite. The study on the occurrence of vanadium by rock ore identification, electron probe and other means that vanadium exists mainly in the adsorption state. Near the interface between mud-siliceous rock and carbon-siliceous rock constructed by carbon-silica mudstone, electron probe analysis of V2O5 content It can reach 9.42%~13.31%; vanadium has a small amount of independent mineral vanadium ore (V205 989%), vanadium iron sharpen mine (V205 26.11%), and iron ore in iron nodules contains V205 up to 5%. According to the ore mineral composition, structure and structure, the main ore type is carbon siliceous rock interbedded with mudstone ore and partially (carbonaceous) mudstone vanadium ore.

(1) Carbon siliceous rock interbedded with mudstone type vanadium ore: consisting of black carbon-silica rock interbedded with mudstone or interbedded layer, with dual mineral composition and structure and structure of carbon siliceous rock type and mudstone type ore, black carbon silica rock The composition of minerals is mainly quartz, quartz content is 65% to 95%; followed by bauxite minerals ( hydromica , kaolinite) 10%, carbonaceous 10%, calcite 1%, limonite 5% to 7%, yellow Iron ore 0.5%, etc. The ore is a cryptocrystalline structure. The composition of mudstone minerals is mainly clay mineral kaolinite and hydromica. The clay mineral content is ≥75%, carbon content is 5%~15%, followed by pyrite, quartz, etc., cryptocrystalline-mud structure and silty structure. .

(2) (carbonaceous) mudstone vanadium ore: mainly composed of mud (page) rock, which may contain individual carbon siliceous rock strips. The composition of minerals is clay mineral kaolinite and hydromica, the clay mineral content is ≥75%, the carbonaceous mudstone ore is 5%-15% carbon, followed by pyrite, quartz, etc., cryptocrystalline and argillaceous structure. , silty structure and algae structure.

Second, the test method

After the original ore is crushed to -2mm, it is reduced to 500g per pack. Each time a pack of ore samples (500g) is added to a cone ball mill (XMQ-67 type), 350mL tap water is added for grinding, grinding to -0.2mm 95%, the slurry is filtered, and dried below 105 °C, both Divide into l00g per pack for backup. Take 1 pack (100g) of mineral powder for each leaching test, place it in a 500mL glass round bottom flask, add human infusion and immersion liquid (a certain concentration of sulfuric acid), with adjustable speed magnetic mechanical stirring device and adjustable temperature control. The device was measured with a 100 ° C thermometer. Under the corresponding conditions, after the leaching is completed, the leaching system is suctioned and washed with a 9 mm Buchner funnel and water extraction. The leaching liquid is marked to a certain volume, and the leaching slag is dried and weighed at 105 ° C; the leaching solution and the leaching slag are respectively pressed. The national standard is analyzed and tested.

Third, the test results and discussion

(I) The effect of sulfuric acid on the leaching rate of vanadium The first thing to do is the sulfuric acid dosage test. The test results are shown in Figure 1.

Other test conditions: liquid-solid ratio 1..1, leaching temperature 90 ° C, leaching time 8 h From the results shown in Figure 1, it can be seen that the leaching rate of vanadium increases with the increase of sulfuric acid dosage, when the amount of sulfuric acid is 8%, vanadium The leaching rate is only 53.71. When the amount of sulfuric acid is 15%, the leaching rate of vanadium is 74.82%. When the amount of sulfuric acid is 20%, the leaching rate of vanadium is 84.86%. Although an ideal leaching effect is obtained, As the amount of sulfuric acid increases, the concentration of free acid in the leachate also increases. When the amount of sulfuric acid reaches 20%, the concentration of free sulfuric acid is as high as 2.20 mol/L (H-concentration is 4.40 mol/L), and so high. The free acid concentration will bring great difficulties to the subsequent vanadium treatment process and increase the production cost. For this reason, we have studied the use of the infusion agent A with sulfuric acid mixed leaching in order to obtain satisfactory results.

(B) the effect of the amount of helper diffusing agent on the leaching rate of vanadium Figure 2 and Figure 3 respectively show the effect of the amount of aid A on the leaching rate of 10% and 12% of sulfuric acid. Two points can be summarized from Fig. 2 and Fig. 3: (1) The effect of the infusion agent is very large, and the leaching rate of vanadium can be greatly improved. When the amount of sulfuric acid is 10%, the leaching rate of vanadium is only 58.25% when no aid is added, and the leaching rate of vanadium is 77% when 2% of the aid is added. When the amount of sulfuric acid is 12%, it is not helpful. The leaching rate of vanadium in the infusion was 63.25%. When 2.5% of the infusion was added, the leaching rate of vanadium reached 88.38%.

Fig. 2 Effect of the amount of assisting agent on vanadium leaching rate when the amount of sulfuric acid is 10% Other test conditions: liquid-solid ratio 1..1, leaching temperature 90 °C, leaching time 8 h (2) The optimum amount of the infusion agent with sulfuric acid The dosage is increased. When the amount of sulfuric acid is 10%, the optimum amount of the infusion agent is 2%; when the amount of sulfuric acid is 12%, the optimum dosage of the infusion agent is 2.5%, which may be related to the infusion agent. It is necessary to consume acid, and the reason why the infusion agent A can effectively increase the leaching rate of vanadium is estimated to be the result of being able to destroy the silicate structure and release the vanadium from the ore, thereby being able to enter the aqueous phase by the action of sulfuric acid.

Fig. 3 Effect of the amount of assisting agent on vanadium leaching rate when the amount of sulfuric acid is 12% Other test conditions: liquid-solid ratio 1..1, leaching temperature 90 °C, leaching time 8h

Other test conditions: liquid-solid ratio 1..1, sulfuric acid 10%, assisting agent A2.5%, leaching time 8h

(III) Effect of leaching temperature on vanadium leaching rate Figure 4 shows the effect of leaching temperature on leaching rate. From the test results, it is very advantageous to increase the leaching temperature for the leaching of vanadium; however, considering that this is atmospheric leaching, if the temperature exceeds 90 ° C, the leaching system generates steam volatilization, which will worsen the operating environment and increase the energy consumption. Therefore, in combination with relevant factors, the leaching temperature is preferably 90 °C.

(IV) Effect of leaching time on vanadium leaching rate The effect of leaching time on vanadium leaching rate is shown in Fig. 5. It can be seen from the figure that the leaching rate increases with time; when the leaching time is 4h, the leaching rate is 74.45%; when the leaching time is 8h, the leaching rate is 77.45%; when the leaching time is 20h, the leaching rate reaches 84.79%.

IV. Industrial test results Through the systematic research of the laboratory, the ideal test results were obtained. On this basis, we conducted industrial tests on site, and the test results are shown in Table 1. Table 1 % of industrial test results

The conditions of the industrial test were: grinding fineness - 0.2 mm 95%; leaching liquid solid ratio was 1..1; leaching sulfuric acid dosage 10%; leaching temperature 90 ° C; leaching time 24 h. The industrial test results verify the results of the laboratory test. Under the same conditions, adding 2% of the leaching agent A, the leaching rate of vanadium is increased from 80.15% to 93.05%, which greatly increases the leaching rate of vanadium and reduces the production cost. , improve resource utilization.

V. Conclusion

(1) The assisting agent A used has a special effect, which can destroy the silicate ore structure and greatly improve the leaching rate of vanadium in the stone coal vanadium ore. (2) In the industrial test, under the same leaching conditions, 2% of the leaching agent A was added, and the vanadium leaching rate was increased from 80.15% to 93.05%. (3) The optimum amount of the aid A is related to the amount of sulfuric acid. The larger the amount of sulfuric acid, the larger the optimum amount of the aid A.

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