Abstract:
|
The unstoppable increasing global demand for metals calls for an urgent development of more
efficient extraction and processing methods in the mining industry. Comminution is responsible
for nearly half of the energy consumption of the entire mining process, and in the majority of the
cases it is far from being optimised. Inside comminution, grinding is widely known for being more
inefficient than crushing, however, it is needed to reach liberation at an ultrafine particle size.
Sometimes the material is excessively reduced in size, while liberation could be achieved at a
coarser scale.
Therefore, in this work a deep characterisation of a specific tungsten ore is performed in order to
find guidance in optimising the processing. Either by discarding and avoiding the unnecessary
crushing of uneconomic material or any other useful recommendation. The aim is that the
methodology utilised for the characterisation of the material, can be applicable to other ores, with
the purpose of initiating the optimisation of the mineral processing.
This thesis is divided in two main parts: the mechanical characterisation of the breakage and the
mineralogical characterisation. For the first part, the breakage behaviour of the sample material
will be studied and described in terms of particle size distribution after interparticle breakage. The
latter will be assessed in terms of the different minerals and tungsten concentrations and mineral
associations, through the use of image analyses (scanning electron microscope), X-Ray diffraction
of crystalline dust and chemical analyses.
The liberation and fracture characteristics that occur due to compressive crushing will be
analysed. Furthermore, recommendations in the processing of the ore will be detailed, along with
potential problems that should be avoided during its exploitation or the own processing.
Results show that it is possible to obtain ore liberation during coarse comminution. Moreover,
preconcentration of the tungsten ore at coarse scale and early rejection of gangue has been
determined to be achievable due to the tendency of the ore to concentrate in specific size
fractions. |