(東北大學(xué) 材料與冶金學(xué)院 多金屬共生礦生態(tài)化利用教育部重點(diǎn)實(shí)驗(yàn)室，沈陽 110819)
摘 要: 根據(jù)高溫水溶液中計(jì)算各反應(yīng)電位、pH及電解質(zhì)活度因子的經(jīng)驗(yàn)公式，通過熱力學(xué)計(jì)算，得到氧分壓為0.5 MPa、對(duì)應(yīng)質(zhì)量濃度為0.1mol/kg的離子活度以及溫度分別為60、100、150和200 ℃條件下V-Fe-H2O系的電位—pH圖。在pH＜2的酸性條件下，V3+、VO2+和VO2+的穩(wěn)定區(qū)一直位于Fe3+和Fe2+的穩(wěn)定區(qū)范圍內(nèi)。隨著溫度由60 ℃提高到200 ℃，可溶性釩鐵離子穩(wěn)定共存區(qū)的pH值逐漸降低，氧化還原電位逐漸提高，釩鐵尖晶石及氧化物的穩(wěn)定區(qū)變化不大。熱力學(xué)研究結(jié)果表明：采用氧壓酸浸工藝能夠?qū)⑥D(zhuǎn)爐渣中的釩充分浸出，但不能通過一步浸出在提釩的同時(shí)將釩、鐵分離，浸出液還需要進(jìn)一步凈化來生產(chǎn)釩制品。轉(zhuǎn)爐釩渣氧壓酸浸的實(shí)驗(yàn)結(jié)果表明：在浸出溫度140 ℃、氧分壓0.5 MPa、粒度0.055~0.075 mm、液固比15׃1(體積與質(zhì)量比)、浸出時(shí)間120 min、攪拌速度500 r/min及初酸濃度200 g/L H2SO4的條件下，釩的浸出率為96.87%，鐵的浸出率為89.25%，實(shí)驗(yàn)結(jié)果與熱力學(xué)計(jì)算結(jié)果相符合。
關(guān)鍵字: 轉(zhuǎn)爐釩渣；氧壓酸浸；V-Fe-H2O系；電位—pH圖
acid leaching of vanadium-bearing converter slags
（Key Laboratory of Ecological Utilization of Multi-metal Intergrown Ores, Ministry of Education,
School of Materials and Metallurgy, Northeastern University, Shenyang 110819, China)）
Abstract:According to the empirical equations of potential (φ), pH and the ionic activity factors of various species, the thermodynamics of V-Fe-H2O system at oxygen partial pressure of 0.5 MPa, ionic activity factor of corresponding concentration of 0.1 mol/kg and temperatures of 60, 100, 150 and 200 ℃ respectively was summarized in the form of (potential—pH) (φ—pH) diagrams. The stable regions of soluble vanadium ions (V3+, VO2+ and ) contained in the region soluble iron ions (Fe3+ and Fe2+) at pH＜2. With the increase of temperature from 60 ℃ to 200 ℃, the pH values of stable regions of V3+, VO2+, , Fe2+ and Fe3+ become more negative and the redox potentials get higher. The stable regions of vanadium iron spinel and other oxides are substantially less affected. The thermodynamic calculation results indicate that vanadium can be extracted by oxygen pressure acid leaching method, but iron cannot be separated by one-step leaching process. The leachate needs to be purified to make vanadium products. The experiment results show that leaching rates of vanadium and iron are 96.87% and 89.25%, respectively, at temperature of 140 ℃, oxygen partial pressure of 0.5 MPa, particle size ranging between 0.055 mm and 0.075 mm, ratio of liquid to solid (ratio of volume to mass) of 15׃1, leaching time of 120 min, stirring speed of 500 r/min and initial acid concentration of 200 g/L. The experimental results are in good agreement with the results of thermodynamic calculation.
Key words: vanadium-bearing converter slag; oxygen pressure acid leaching; V-Fe-H2O system; potential—pH diagram
