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Mining has been embedded in the public consciousness as a dirty, non-innovative, outdated and environmentally harmful industry. Proper education, especially the academic one, becomes crucial to successfully change this image. This article depicts the initial assumptions of the international project Master in Entrepreneurship, Innovation and Technology Integration in Mining (MEITIM), co-financed by EIT Raw Materials, that aims to diagnose the current state of Polish higher education in the field of mining at, among others, the Wroclaw University of Science and Technology (WUST), concerning the experience of the Technical University of Madrid (UPM) and Lappeenranta University of Technology (LUT). The MEITIM project allowed identifying the directions of necessary changes in the didactic process as an indispensable set of skills and knowledge for a future mining graduate. Such activities are dictated by many guidelines and arrangements, among others, at the level of the European Commission or key industry institutions such as the International Council on Mining and Metals. These are key competencies that require significant changes in university curricula supporting sustainable development goals in innovative mining. The authors show that there is a link between the condition of the mining industry in Poland, its reputation, and the number of people who want to study mining.

In the current study, a numerical mechanistic kinetic model for direct leaching of zinc from iron containing sphalerite concentrate is presented. The model is based on the well-known shrinking-core model approach. However, in order to consider possible chemical changes that might take place in the liquid phase the model is solved numerically. This also makes it possible to separate and quantify different factors that might limit the leaching process. It is suggested that the most probable leaching mechanism is a combination of the acid attack and electrochemical reaction mechanisms. At first, zinc sulphide reacts with hydrogen ions at the surface of particles liberating zinc ions and forming hydrogen sulphide. Then in the next step, hydrogen sulphide is oxidized by ferric ions or molecular oxygen according to an electrochemical reaction mechanism. The estimated reaction orders for the oxidants are close to 0.5 which supports the electrochemical mechanism. The mechanism of sphalerite leaching also involves simultaneous surface reactions and internal diffusion of oxidants. The obtained results show that the rate of the leaching process is mainly limited by the surface reactions. However, internal diffusion might decrease the leaching rate in some cases up to 50% at higher sphalerite conversions. It is also demonstrated in the study that by using advanced statistical mathematical methods, such as the Markov chain Monte Carlo method, new information can be obtained about the kinetics of sphalerite leaching, the parameters affecting the leaching rate and the uncertainties involved in the model predictions.

A non-cyanide lixiviant for gold dissolution, cupric chloride, was studied. The work used a rotating disk electrode technique to investigate the dissolution reaction mechanism and kinetics of gold dissolution in concentrated chloride (3 M) solution with cupric ion concentration in the range 0.02–1.0 M and temperature 65–95 °C. A reaction mechanism including a disproportionation step of Au(I) is proposed. Increase in the gold dissolution rate was found to be proportional to temperature and cupric ion concentration up to 0.5 M. The dissolution rate was observed to decrease with cupric ion concentration of 1.0 M. A mechanistic kinetic model was developed to study the rate-controlling steps in the dissolution process. Uncertainties in the model parameters of the mechanistic kinetic model were studied with Markov chain Monte Carlo (MCMC) methods. The modeling results showed that the gold dissolution is mainly under mixed control, where both the intrinsic surface reaction and mass transfer have an effect on the overall dissolution rate.

Gold dissolution was investigated in ferric chloride solution, being one alternative cyanide-free leaching media of increasing interest. The effect of process variables ([Fe3+] = 0.02–1.0 M, [Cl−] = 2–5 M, pH = 0–1.0, T = 25–95 °C) on reaction mechanism and kinetics were studied electrochemically using rotating disk electrode with ωcyc = 100–2500 RPM and Tafel method. The highest gold dissolution rate (7.3 · 10−4 mol m−2 s−1) was achieved at 95 °C with [Fe3+] = 0.5 M, [Cl−] = 4 M, pH =1.0 and ωcyc = 2500 RPM. Increase in gold dissolution rate was observed with increase in temperature, ferric ion concentration and chloride concentration, but gold dissolution rate did not have a clear dependency on pH. Redox potential was found to vary between 636 and 741 mV vs. SCE during experiments. According to the calculated equilibrium and measured open circuit potentials, gold was suggested to dissolve as aurous ion Au+ and form AuCl2 −, rather than auric ion Au3+ and form AuCl4 −. Further, it is suggested that AuCl2 − does not oxidize to AuCl4 − under the investigated conditions. Levich plot and the calculated activation energies suggested that gold dissolution was limited by mass and electron transfer. According to a mechanistic kinetic model developed in the current work, intrinsic surface reaction mainly controls gold dissolution, especially at higher rotational speeds (>1000 RPM). Uncertainties in the model parameters of the mechanistic kinetic model were studied with Markov chain Monte Carlo methods.

In this study, direct leaching of zinc sulfide concentrate was investigated in a solution that resembles the composition of solutions used in industrial leaching processes. The effect of different factors (temperature, Fe 2 + –Fe 3 + -concentration, H 2 SO 4 -concentration, SO 4 -concentration, pressure, size of the concentrate particles) on the rate of the zinc sulfide concentrate leaching was studied experimentally. H 2 SO 4 -concentration had no influence on the leaching kinetics. The obtained experimental data were used to model the reaction kinetics with mechanistic models as well with a more empirical model, and the reliability and the accuracy of the model parameters were studied with Markov Chain Monte Carlo (MCMC) methods. The model that best describes the leaching system (R 2 = 97%) takes into account the reactions between the zinc sulfide concentrate and oxidizing agents at the reacting surface of the concentrate particles, the decrease in the active surface area of the concentrate particles as the leaching proceeds, the particle size distribution of the concentrate particles, the composition of the solution, and the oxidation rate of Fe 2 + to Fe 3 + . The experimental results together with the modeling results clearly demonstrate that it is important to have experimental data for the kinetics of the leaching at the conditions of the reactor.

Ammoniacal thiosulfate leaching of pressure oxidized sulfide gold concentrate received from a gold mine is studied. The main chemical composition of the concentrate was Au 32 g/t, Ag 12 g/t, Fe 59%, S 21% and As 19%. The experimental variables studied were ammonia concentration, thiosulfate concentration, copper concentration, and temperature. The highest gold extraction (89%) was achieved with the following leaching solutions: 0.2 mol S2O3/L, 0.2 mol NH3/L, and 0.1 g Cu/L; and with the following conditions: solids, 30 m-%; pressure, 1 atm; continuous aeration (0.2 L/min); temperature, 30 °C; and leaching time, 6 h. Measured thiosulfate and copper concentrations after 6 h of leaching were 0.19 M and 0.08 g/L, respectively. The results from the leaching experiments showed that the pressure oxidized gold concentrate was effectively leached in an ammoniacal thiosulfate leaching solution with minimal reagent consumption. The study shows that the widely reported problem of high reagent consumption can be circumvented in leaching of pressure oxidized sulfide gold concentrate by the use of low reagent concentrations. The results indicate good premises for gold recovery by ion-exchange resins, since minimal thiosulfate consumption also ensures low polythionate concentration, which is an important issue in gold recovery with ion-exchange resins. The minimal reagent consumption also indicates that there are good possibilities to circulate the leaching solution for re-use in the leaching stage after gold recovery and solid–liquid separation.