Hypersaline inorganic brines are generated from many global mining operations and the volume of these brines is increasing at an exponential rate. The environment and water resources in the vicinity of these mining operations are at a risk of being polluted as a result of this increase in brine volume. These are the key reasons why these brines need treatment. Eutectic Freeze Crystallization (EFC) has been identified as a possible novel brine treatment method, but to date it has not been applied to multi-component streams such as brines. Therefore, the aim of this thesis was to develop a brine treatment protocol and to demonstrate the "proof of concept" of EFC as a brine treatment method. Three key aspects essential to the brine treatment protocol were identified as being crucial to the treatment process. These key aspects were brine analysis, thermodynamic modelling and kinetic aspects. A combination of standard water analysis techniques and wet chemistry were used to characterize the brine, while OLI Stream Analyser was used to perform the thermodynamic modelling of the brine. It was found that the difference between the total cations and total anions (ion imbalance) from the analysis of two brine samples, Brine 1 and Brine 2, were 5.8% and 6.3% respectively. The brines were also very dilute with a total dissolved solid content of 29.77g/L for Brine 1 and 31.26g/L for Brine 2. OLI Stream Analyser was able to predict and simulate the phase equilibria of an aqueous system over a wide temperature range by estimating the standard state terms and the excess terms with the use of various thermodynamic frameworks. This was an important step because the identities of the potential salts, the temperatures at which they would crystallize and the potential yields of the various products could be predicted before any experiments were conducted. The thermodynamic modelling predicted that the brine samples were saturated with respect to CaS04·2H20. The modelling also predicted that ice, Na2S04·10H20 as well as K2S04·CaSOdH20 would crystallize in a narrow temperature range from -O.8°C to -2.2°C. The thermodynamic results also showed that a high overall ion recovery (85% for Brine 1 and 71 % for Brine 2) would be obtained at an operating temperature of -5°C. However, the thermodynamics merely offered a prediction. It was only by investigating the kinetic aspects of the system that the identity, crystallization temperatures and yield of products could be confirmed. The kinetic aspects incorporated three phases. The first phase focused on determining the metastable zone (MSZ) of ice in a binary sodium sulphate solution, as well as the MSZ of ice for the brine. This essentially defined the operating region in which heterogeneous ice nucleation could occur. The results confirmed the inherently stochastic nature of nucleation and showed that a number of experiments were needed in order to define the MSZ. The MSZ for a 1 wt% sodium sulphate solution (1.8ml volume) was 2.56 ~oC for a cooling rate of 2°C/hour, 2.76 ~oC for a cooling rate of 4°C/hour and 4.76 ~oC for a cooling rate of 8°C/hour. The effect of solution volume on the nucleation process and hence the MSZ was determined. The MSZ for a 250ml, lwt% solution and a 1000ml, lwt% solution were similar (2.3 ~OC and 2.2 ~OC respectively). The second kinetic phase investigated the problem associated with the crystallization of two salts and ice. The EFC process is based on the principle that ice can be separated from a salt because of their density differences, thus producing pure products. However, if two salts crystallize at the same conditions, then salt contamination would occur (similar densities for the salts). This problem was avoided by utilizing knowledge obtained from phase diagrams and by seeding with a specific salt. It was found that seeding as a separation technique was feasible in a ternary Na2S04-MgS04-H20 system. The addition of Na2SOd OH20 seeds to a supersaturated solution at 12°C resulted in pure Na2S04.10H20 (96% purity) being formed. The third kinetic phase focused primarily on the sequential removal of pure salts from a single brine during EFC conditions. The experimental work showed that pure calcium sulphate (98.0% purity), pure sodium sulphate (96.4% purity) and potable water (ice) could be formed with a brine mass reduction of ~97%. The problem with the brines initially being saturated with respect to calcium sulphate was also solved by successfully removing calcium sulphate and ice under EFC conditions. This meant that pure sodium sulphate and ice could be removed in the subsequent stage. This thesis ultimately showed that EFC could be used to treat multi-component streams and that pure salts could be sequentially produced along with potable water.

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