The processing of laterite ores for the recovery of nickel and cobalt has increased as the reserves of exploitable sulphide ores have become depleted. The pressure acid leach process (PAL) has become the preferred option for the treatment of laterite ores. Difficulties associated with the poor settling characteristics of the pulp in the counter current decantation (CCD) circuit after pressure leaching has resulted in as much as 10% of the soluble nickel and cobalt reporting to the tailings. The objective of this project is the development of an alternative processing step for the recovery of soluble nickel and cobalt from the PAL tailings using resin-in-pulp (RIP) technology. Commercially available chelating resins with the iminodiacetate functional group have been studied for their suitability for the adsorption of nickel and other metal ions from PAL tailings pulp. The Amberlite IRC 748 resin was found to be superior despite its lower nominal loading capacity. The resin with the highest nominal capacity was observed to adsorb less nickel as a result of the adsorption of greater amounts of the impurity ions. The equilibrium loading for nickel on the preferred resin was found to be similar from the ammonium and protonated form of the resin although the kinetics of adsorption is greater when the resin is initially in the ammonium form. A comprehensive study has been made of the equilibrium adsorption of several metal ions on the resin as a function of the equilibrium pH of the solution. A relatively simple model of the equilibrium adsorption which includes the effect of pH has been developed ii and the results compared with the experimental data obtained in the M2+/Na+/H+ system. The model which requires two equilibrium constants has been found to fairly well describe the experimental results. A study of the kinetics of the loading of nickel and cobalt from both solutions and pulp has shown that the rate can be described in terms of a first-order approach to equilibrium. The kinetic and equilibrium parameters were used to simulate the performance of a multi-stage counter current resin-in-pulp operation A semiquantitative study of the elution of the adsorbed metal ions from the resin by dilute sulphuric acid solutions was also undertaken. The technical feasibility of the RIP process for the recovery of nickel and cobalt from the PAL tailings has been successfully demonstrated in both laboratory and pilot-plant studies using a five-stage adsorption process. Important parameters such as the operating pH and the residence times of pulp and resin in each stage were identified through the batch test work coupled to the simulation procedure. The optimum pH for adsorption was found to be in the range 4 to 5 as this pH is high enough to maximise the adsorption of nickel and cobalt while preventing precipitation of nickel and cobalt as hydroxides from the pulp. A method for minimizing the competition from more strongly loaded ions such as iron(II) and chromium(III) which are present in the pulp was also developed in the initial laboratory phase of the project and utilized during the pilot operation. Problems associated with the preparation of the pulp preparation, elution of the loaded resin and control of the adsorption train were resolved during several pilot plant runs on site at a local PAL plant. These and other minor improvements and adjustments to the operating procedure culminated in a successful continuous run for several days during which the target recovery of 90% for nickel and 60% for cobalt was exceeded throughout the run.

The production of sand can be a major issue in many young, unconsolidated sandstone formations where there is little to no cement holding the individual sand grains together. When such reservoirs are produced, quite often operators face problems with reduced well productivity and equipment failure. Because of these issues, the industry has developed numerous techniques in its effort to control formation sand production. Sand consolidation is one technology that has been studied and used since the 1940s. The theory behind sand consolidation technology is to place a liquid material which will create a grain to grain contact that will bind individual sand grains together. Most consolidation treatments contain a preflush to clean and wet the surface, the consolidating system to bind the sand grains and give residual strength, and, finally, an overflush to ensure the formation is still able to produce fluids. With the successful placement of this fluid, the sand grains will be locked in placed so that they will not be produced. The technology has gone through many phases of conception since the 1940s; however, most consolidation material that is pumped in the past has been based upon an epoxy or furan backbone. While there are many technologies available, for the purpose of my research, the epoxy technology was experimentally investigated. The testing of the fluid involved investigating numerous additives to obtain the correct residual strength of the sample, as well as the necessary retained permeability. For the epoxy fluid, the optimal preflush, epoxy system and overflush formulations were determined after 250 checkout tests. Based upon these tests, the fluid was optimized to its working time and UCS results. The optimal system included the addition of PA2 to the preflush, along with PA1 and an aromatic amine curing agent to the epoxy system. PA1 and PA2 are adhesion promoter additives which were deemed necessary as a result of the testing. This system was then tested further in a HP/HT cell. While there is still room for improvement with respect to retained permeability, the system still performs very well in terms of UCS.

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