沉积型赤铁矿、菱铁矿和黄铁矿氧化还原电位测量及其地球化学意义

Measurement of Redox Potential of Sedimentary Hematite, Siderite and Ryrite and Its Geochemical Significance

在沉积型矿物粉末中加入强氧化剂高锰酸钾溶液,配制成悬浮液,矿物中的还原组分与高锰酸钾溶液发生氧化还原反应。用一台精密电位计可测量反应过程中的氧化还原电位值(AEh)。赤铁矿标志着氧化环境,△Eh为 7mV; 菱铁矿标志着还原环境,△Eh为37mV;黄铁矿标志着强还原环境,△Eh为83mV,三种矿物代表着三种沉积环境。这表明,矿物地球化学环境法与氧化还原电位法所获得的结论是一致的。

The redox reaction between the reduction components in mineral and the solution of oxidizer will take place if we put the powder of sedimentary minerals into the solution of strong oxidizer (such as KMnO4) to prepare a suspended liquid. The redox potential (△Eh) in the reaction process can be measured by a precision potentiometer. Hematite with a △Eh of 7mV marks an oxidation environment; siderite with a △Eh of 37mV stands for a reduction environment; and pyrite with a △Eh of 83mV represents a strong environment. The minerals mentioned above represent three distinct sedimentary environments because of great difference in △Eh. This shows that the results measured by redox potential method are consistent with that of the geochemical environment method.