Liberation Characteristics of Ta–Sn Ores from Penouta, NW Spain

Abstract

The strategic importance of tantalum and its scarcity in Europe makes its recovery from low grade deposits and tailings interesting. In Penouta, the contents of Ta and Sn in old tailings from an Sn mine are of economic interest. Due to the relatively low grade of Ta of around 100 ppm, a detailed study of the mineralogy and liberation conditions is necessary. In this study, the mineralogy and the liberation characteristics of Sn and Ta ores of the Penouta tailings were investigated and compared with the current leucogranite outcropping ores. The characterization was conducted through X-ray diffraction, scanning electron microscopy, and electron microprobe. In addition, automated mineralogy techniques were used to determine the mineral associations and liberation characteristics of ore minerals. The grade of the leucogranite outcropping was found to be about 80 ppm for Ta and 400 ppm for Sn, and in the tailings used for the liberation study, the concentrations of Ta and Sn were about 100 ppm Ta and 500 ppm Sn, respectively. In both, the leucogranite outcropping and tailings, the major minerals found were quartz, albite, K-feldspar, and white mica. Ore minerals identified were columbite-group minerals (CGM), microlite, and cassiterite. The majority of CGM examined were associated with cassiterite, quartz, and muscovite particle compositions and cassiterite was mainly associated with CGM, quartz, and muscovite. The liberation size was 180 µm for CGM.

Recovery of Tantalum from Different Resources

“…In Europe there are known deposits of niobium and tantalum in Finland and Norway, but they cannot be economically exploited using conventional processes. There are some deposits of niobium and tantalum in Spain that could be exploited in satisfactory economic conditions [26]. Tantalite and columbite are the main sources of tantalum and niobium in the Penouta mine.…”

Editorial for Special Issue “Mineral Liberation”

“…This is the case of flotation, where the dimensions and shape of the particles play an important role [15]. This is shown by Rong et al [3], who analyse the effect of the shape of particles obtained from different comminution methods on low-rank coal flotation. They investigate the length-diameter ratio, wrap angle, and bubble-particle attachment/detachment of rod-milled and crushed coal particles.…”

“…In relation to mineral liberation, two aspects must be addressed: (1) the characterization of the raw materials to be processed, and (2) the variation of the liberation characteristics according to the treatment to reduce the particle size. This issue covers both topics: techniques of mineral liberation characterization of ores before treatment [2,3], and the relationships between comminution and mineral liberation, taking into account the energy consumption [4][5][6][7][8].…”

“…Three articles from this issue report results of the Increasing yield on Tungsten and Tantalum ore production by means of advanced and flexible control on crushing, milling and separation process (OPTIMORE) European project [3,6,7]. The main objective of OPTI-MORE was to optimize the crushing, milling, and separation ore processing technologies for tungsten and tantalum mineral processing.…”

“…The mineralogical characteristics of the liberation of these ores were presented before in a Special Issue of Minerals devoted to the process mineralogy of critical raw materials [13,14,18]. Alfonso et al [3] determine the liberation characteristics of Penouta tailings and compare the results with those from outcroppings of leucogranite low-grade tantalum ore. The characteristics of mineral liberation were quantified for columbite-group minerals and cassiterite.…”