深穿透地球化学样品中铜活动态提取条件研究与初步应用

Leaching Conditions for the Determination of Mobile Forms of Copper in Deep-penetrating Geochemical Samples and Its Preliminary Application

深穿透地球化学是通过提取地表土壤中深部隐伏矿发出的元素直接信息的找矿方法,元素活动态提取是应用最广的方法之一。但地表土壤中元素活动态含量信息微弱,活动态提取、元素分析的过程复杂,分析误差容易掩盖有效信息。目前的研究对提取过程条件缺乏有效的控制,方法标准化程度不高。本文研究了深穿透地球化学样品中活动态铜的提取条件,包括提取固液比、提取时间、提取液pH、固液分离方法、提取温度等,对提取过程进行优化,采用电感耦合等离子体质谱法测定铜的含量,方法检出限为0.03μg/g,精密度(RSD)为4.95%～7.39%。方法操作简单,精密度较好,应用于河南某隐伏铜多金属矿的探测,通过分析矿床的铜总量和活动态铜的含量,发现在矿床土壤中探测到了较为明显的与深部矿体成矿元素的活动态异常,探测结果所圈定的异常与实际矿(化)体相符。

Deep-penetrating geochemistry is one of the exploration techniques to detect elemental information contained in the surface soils and transported through the covering of the concealed deposit. The selective leaching of mobile forms of elements is one of the most popular techniques. Since the contents of mobile forms of elements are always at the trace level, valuable information is easily concealed by the analytical errors caused from the complex leaching and determination procedures. At present, research on the leaching conditions is limited, and the degree of standardization of methods is poor. Experiments have been conducted for leaching conditions of determination for mobile forms of copper in deep-penetrating geochemical samples and are described here. The analytical parameters include solid-liquid mixing ratio, extraction time, pH, solid-liquid separation method and extraction temperature, as well as the determination method for extraction solution. The copper in leached solution was determined by Inductively Coupled Plasma-Mass Spectrometry （ICP-MS） with detection limit of 0.03 μg/g andRSD of 4.95% -7.39%. The method was simple and highly accurate. The method was applied in one buried Cu-Ni deposit in Henan Province and the results were obtained from the contents of total Cu and mobile Cu, showing that the delineated anomalies were consistent with the actual ore bodies.