Task 3.1. – Comminution (M6-M12)

In general, comminution includes crushing, milling and other routes of fragmentation of a material, such as “MicroWave” (MW) pretreatment or electrical fragmentation. This step of preparation of material is an energy-intensive process and then it is evident to choose the optimized type of comminution technique for cost-effectiveness of a process. MW pre-treatment may facilitate the grinding process by reducing work index and improves the liberation of particles. To avoid the production of fine particles during grinding process, there are other innovative techniques. In this project, different methods of comminution routes will be compared, in order to achieve the liberation of individual phases from matrix required for physical separation:

  1. smart size reduction or soft grinding (sequential grinding), using grinding followed by classification to recover metals each step;
  2. electrical fragmentation: this technique has been used on ore aggregates and generated a higher percentage of liberated particles and lower percentage of fine material than that obtained by mechanical comminution.

Crushing, milling and MW heating will be carried out at BRGM on laboratory scale level. Electrical fragmentation will be tested by BRGM on equipment located in Switzerland. The work index will be determined. The reduced material will be characterized by “Mineral Liberation Analyses” (MLA), combined with conventional analyses, to evaluate the comminution efficiency. These analyses will allow to measure, aside from the comminution efficiency, the influence of the comminution process on the physicochemical properties of the material (liberation degree of particles, distribution of metal-bearing phases, activation). The material, obtained by the optimized comminution processes, will be further treated in task 3.2.


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