根据稀土元素在矿石中的存在形式及其成因、开发利用对象,当前将稀土矿床划分为原生型、砂矿型、风化壳离子吸附型等三种工业类型.原生型矿床其稀土元素绝大部分呈矿物相形式存在,选矿工艺一般为浮选,并常辅以重选、磁选而组成联合工艺,开发利用对象为稀土矿物中的稀土,一般工业品位以稀土氧化物百分含量(即“总量”品位)表示.风化壳离子吸附型矿床稀土元素则以可交换阳离子吸附态(也称离子相)赋存于风化壳粘土中为主,但存在较大比例尚不能被利用的其它相态,选矿采用浸提工艺,利用对象为可交换并能被浸出的那部分稀土,其现行一般工业品位也以稀土氧化物含量表示.勘查开发研究实践表明,该指标由于包含尚不能被利用的其它相态稀土,而且这部分稀土在不同的矿区占有率高低相差很大,仅凭该指标圈定的矿体无法真实反映可利用资源分布状态与特征,不适用该类矿床的勘查评价,宜修订为与利用对象一致的可交换阳离子稀土氧化物含量(即“浸出量”品位)表示.
According to the difference of existing types,formation and exploited constituent,the rare earth elements (REE) deposits can be divided into three industry types including endogenetic,sand sedimentary,and ion-adsorption types.The REEs at endogenetic deposits mostly form minerals mainly separated by floating separation method associated with gravitational and magnetic separation methods,and their industry grade is represented by the total quantities of rare earth oxides (TREO).But the REEs at ion-absorption deposits always exist as exchangeable positive ions sticking to the clay minerals in the weathering crust,which can not be extracted completely and are separated with leaching method with industry grade represented by the TREO.The results from exploration and exploitation prove that the TREO cannot precisely stand for the distributions and features of the ion-absorption REE resource,because the weathering crust contains REE in other phases which cannot be separated by leaching method.Therefore,the TREO currently used index may be not applicable for the ion-absorption REE resource,and the separated quantities of rare earth oxides (SREO) should be provided as the new index for the future exploration evaluating.
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