离子型稀土原生矿床及原地浸析尾矿中稀土和铵的分布特征

发布时间：2018-06-12 23:41

本文选题：离子吸附型稀土 + 原地浸析　；参考：《南昌大学》2015年硕士论文

【摘要】：离子吸附型稀土原地浸析采矿技术的明显优势是对植被的破坏程度小。但也存在诸多不确定因素,从而导致稀土收率低、水土和资源流失严重乃至塌方滑坡等问题。为此,需要对原地浸析的实际效果和问题进行深入研究,寻找提高稀土提取效率、减少环境影响的技术措施。本文以龙南、安远、寻乌等地的几个典型离子吸附型稀土矿床及原地浸析尾矿为研究对象,采集了不同空间位置的样品,并对稀土和铵含量进行了测定。通过比较原生矿床及尾矿中铵和稀土含量的空间分布特点以及重轻稀土含量比的变化规律来探讨原地浸析技术的问题及改进措施。结果表明:由于全风化层的渗透性好,原地浸析陈年尾矿中的稀土和铵残留量均比较低,且表层和半风化层区域要比全风化层的高,从全风化层到半风化层方向铵和稀土残留量均呈上升趋势;而原地浸析在浸尾矿中的铵含量大大高于陈年尾矿,且稀土含量与铵含量呈反比关系,不同部位的稀土残留量随深度的变化关系也有所不同。测定的矿中粘土矿物对稀土和铵的吸附等温线分别呈优惠型和线性关系,说明尾矿与水接触时残留铵是容易流失的,而稀土是稳定的。因此,陈年尾矿风化层中铵含量低与雨水渗浸导致的铵流失直接相关。原生矿床与尾矿中的酸性随深度的变化规律也意味着尾矿中的铵可以通过逸出氨气并释放出氢离子的途径而降解。这样,尾矿中铵的残留量分布与矿层的渗水性和透气性相关。据此,可以根据尾矿中铵和稀土残留量的分布来讨论离子吸附型稀土矿床内部的结构与渗流特征。同时还发现,原矿中重轻稀土比值随深度的变化与原矿中稀土总量随深度的变化相一致,但其峰值不同步,重轻稀土比值的峰值总是滞后稀土总量峰值1~2米;而尾矿中重轻稀土的比值跟稀土的浸出率呈负相关性,即重轻稀土比值低的区域,其稀土浸出率一般也较高;据此,尾矿中铵和稀土残留量分布以及稀土配分值的变化均可用来评价稀土浸出的完全程度,为计算稀土回收率提供依据。
[Abstract]:The obvious advantage of ion adsorption rare earth in situ leaching mining technology is that the destruction degree of vegetation is small. However, there are many uncertain factors, such as low rare earth yield, serious soil and water loss and even landslide. Therefore, it is necessary to deeply study the practical effect and problems of in situ leaching, to find technical measures to improve the extraction efficiency of rare earth and to reduce the environmental impact. In this paper, several typical ion adsorbed rare earth deposits and in situ leached tailings from Longnan, Anyuan and Xunwu were studied. Samples of different spatial positions were collected, and the contents of rare earth and ammonium were determined. By comparing the spatial distribution characteristics of ammonium and rare earth contents in primary ore deposits and tailings and the variation law of the ratio of heavy to light rare earth elements, the problems of in-situ leaching technology and its improvement measures are discussed. The results show that the residual amounts of rare earth and ammonium in the aged tailings of in-situ leaching are lower, and the surface layer and semi-weathered layer area are higher than that of the total weathering layer, due to the good permeability of the total weathering layer. In the direction of total weathering to semi-weathering, the content of ammonium and rare earth residues in leaching tailings is on the rise, and the content of ammonium in in-situ leaching tailings is much higher than that in aged tailings, and the content of rare earth elements is inversely proportional to the content of ammonium. The relationship between the rare-earth residues and the depth is also different. The adsorption isotherms of rare earth and ammonium for clay minerals in the ores are preferential and linear respectively, which indicates that the residual ammonium is easy to be lost when the tailings are in contact with water, but the rare earth is stable. Therefore, the low content of ammonium in weathering layer of aged tailings is directly related to the loss of ammonium caused by Rain Water infiltration. The variation of acidity with depth in primary ore deposit and tailings also means that ammonium in tailings can be degraded by the way of releasing ammonia and releasing hydrogen ions. Thus, the distribution of ammonium residues in tailings is related to the permeability and permeability of ore beds. According to the distribution of ammonium and rare earth residues in tailings, the structure and percolation characteristics of ion adsorbed rare earth deposits can be discussed. At the same time, it is found that the ratio of heavy, light and light rare earths in raw ore varies with the depth, but the peak value of the ratio of heavy to light rare earth is not synchronized, and the peak of ratio of heavy to light rare earth always lags behind the peak of total rare earth by 1 ~ 2 m. However, the ratio of heavy and light rare earths in tailings is negatively correlated with the leaching rate of rare earths, that is, where the ratio of heavy to light rare earths is low, the leaching rate of rare earths is generally higher. The distribution of ammonium and rare earth residues in tailings and the change of rare earth fraction can be used to evaluate the complete degree of rare earth leaching and provide the basis for calculating the recovery rate of rare earths.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD926.4

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