热-水-力-化学耦合作用下Ca0.86Nd0.14Ti0.86Al0.14SiO5固溶体的化学稳定性
Stability of Ca0.86Nd0.14Ti0.86Al0.14SiO5 Solid Solution by Coupling Effect of THMC
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摘要: 以CaCO3、Nd2O3、TiO2、SiO2、Al2O3为原料，用固相法制备掺钕榍石固溶体（Ca0.86Nd0.14Ti0.86Al0.14SiO5）。采用PCT法进行浸泡实验，借助X射线衍射（XRD）、扫描电镜（SEM）、电感耦合等离子体发射光谱（ICP-OES）等分析手段，研究掺钕榍石固溶体在热水力化学（THMC）耦合作用下的化学稳定性。结果表明，在pH值为5～9、温度150～200 ℃、压强0.476～1.554 MPa的耦合作用下，Ca0.86Nd0.14Ti0.86Al0.14SiO5固溶体具有良好的化学稳定性；pH值、温度（压力）对Ca0.86Nd0.14Ti0.86Al0.14SiO5固溶体中Si4+、Al3+、Nd3+的归一化浸出率无明显影响；Ca2+在200 ℃（1 554 MPa）时的抗浸出性能较150 ℃时的好；在浸泡初期（1～21 d）Ca2+在pH值为9时的抗浸出性能优于pH值为5和7时的，浸泡后期（28、42 d）3种溶液中固溶体的Ca2+抗浸出性能趋于一致；Ti4+在pH值为9时的抗浸出性能较pH值为5和7时的好。Abstract: Sphene solid solution doped neodymium (Ca0.86Nd0.14Ti0.86Al0.14SiO5) was prepared using CaCO3,Nd2O3,TiO2,SiO2 and Al2O3 as raw materials by solidreaction. The chemical stability of sphene solid solution doped Nd by the coupling effect of thermodynamics-hydrodynamics-mechanics-chemistry (THMC) was investigated by the means of product consistency test (PCT), X-ray diffraction (XRD), scanning electron microscope (SEM), inductively coupled plasma atomic emission spectrometry (ICP-OES) and so on. The results indicate that Ca0.86Nd0.14Ti0.86Al0.14SiO5 solid solution has good chemical stability by the coupling effect of the pH＝5.9, 150-200 ℃ and 0.476-1.554 MPa; the pH value and temperature (pressure) have no significant impact on the normalized leach rate of Si4+, Al3+ and Nd3+; the anti-leaching property of Ca2+ at 200 ℃ (1.554 MPa) is better than that at 150 ℃; early in the immersion, the anti-leaching property of Ca2+ in pH=9 is better than that in pH＝5 and 7, late in the immersion, the anti-leaching property of Ca2+ in solid solution is converge in the three solution; the antileaching property of Ti4+ in pH＝9 is better than that in pH＝5 and 7.
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Keywords:
- sphene ,
- solid solution ,
- coupling ,
- normalized leach rate
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