The leaching process is controlled by mixed steps:the surface chemical reaction and the diffusion passing through the silicon and iron mineral phases.

浸出过程属于混合控制，即表面化学反应与通过不溶硅、铁矿物相的扩散为过程的控制步骤。

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And the paper emphasized on the interface reaction mechanism, diffusion mechanism and metallic phase transformation mechanism which is controlled by activation.

重点介绍了以界面反应为主、扩散为主的反应机理和活度控制的金属相变机理。

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For isomerization of o-xylene the improvement in para-selectivity has not been observed, because the reaction is not mainly controlled by the diffusion of the reaction products.

但对邻二甲苯异构化反应，由于反应不是单纯由反应产物扩散控制，它们的对位选择性并无明显改善。

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