(中南大學(xué)冶金與環(huán)境學(xué)院，長沙 410083)
摘 要: 針對(duì)植酸鹽分解白鎢礦的問題，繪制了298 K溫度下Ca-Phy-W-H2O體系的熱力學(xué)平衡圖，闡明了體系中各物質(zhì)的優(yōu)勢(shì)區(qū)域、重要組分隨pH值和游離植酸總濃度的變化規(guī)律，進(jìn)一步研究植酸鹽分解白鎢礦的可行性及熱力學(xué)條件。理論分析表明，植酸鹽可有效分解白鎢礦，隨著pH值的升高，穩(wěn)定生成的固相產(chǎn)物依次為H2WO4、CaWO4和Ca6Phy。當(dāng)體系pH＞7.5后，Ca2+與Phy12-的結(jié)合作用急劇增強(qiáng)，導(dǎo)致游離 濃度迅速上升，在pH＞10之后趨于平緩，此時(shí)固相分解產(chǎn)物為Ca6Phy。溶液中維持較低濃度的游離植酸即可實(shí)現(xiàn)白鎢礦的分解，同時(shí)提高溶液的pH可促進(jìn)白鎢礦的分解。
關(guān)鍵字: Ca-Phy-W-H2O體系；白鎢礦；植酸鹽；熱力學(xué)；分解
（School of Metallurgy and Environment, Central South University, Changsha 410083, China）
Abstract:In order to solve the problem of scheelite decomposition by phytate, the thermodynamic equilibrium diagram of Ca-phy-W-H2O system at 298 K was drawn. The variation law of dominant regions and important components in the system with pH and total concentration of free phytic acid was clarified. The feasibility and thermodynamic conditions of phytate decomposition scheelite were further studied. Theoretical analysis shows that phytate can effectively decompose scheelite. With the increase of pH value, the stable solid products are H2WO4, CaWO4 and Ca6Phy. When pH＞7.5, the binding of Ca2+ and Phy12- increases rapidly, resulting in a rapid increase in the concentration of free and insignificant increase after pH＞10. At this time, the solid phase decomposition product is Ca6phy. The decomposition of scheelite can be achieved by maintaining a low concentration of free phytic acid in the solution, and increasing the pH value of the solution can promote the decomposition of scheelite.
Key words: Ca-Phy-W-H2O system; scheelite; phytate; thermodynamics; decomposition
