A severe shortage of many, to mankind, valuable elements are to be expected in the near future. Therefor is it of utmost importance to find these deposits and a way to refine the elements with as little negative effect on the environment as possible. One deposit of valuable elements such as U, V, Mo and Sr are the so called alum shale. Alum shale is a variety of sulfidic black shale which is rich in pyrite, FeS2, and organic carbon. Primary due to its contents of hydrocarbons and uranium the alum shale has been mined at different sites throughout Sweden. One of these sites was Kvarntorp in the region of Närke. The shale which had have its contents of hydrocarbons extracted through dry distillation was dumped into a heap that is now known as Kvarntorpshögen. The remaining hydrocarbons that this processed material still contain are to this day (2011) warm, with temperatures up to some hundred degrees Celsius. Due to this heat, infiltration of rainwater is held at a minimum. What no one knows however; is for how long Kvarntorpshögen will remain warm. Once it cools; many toxic elements will leak into the surrounding environment due to natural weathering caused by precipitation and frost wedging. The study also included a heating treatment of 70°C which is a temperature that the material of Kvarntorpshögen may be capable of generating by itself. This is assumed to be a good temperature for weathering processes; because it increases the kinetics of chemical reactions but also allows the presence of water. The results of this study shows that summer will be the season that contributes the most to the leaching of elements, of which some are toxic. Newly exposed surfaces of various shale materials often contain elements that is easily leached by water. Once this coat is washed away however, further leaching of that element decreases. Exceptions from this pattern in some shale products were shown by for example vanadium and molybdenum. The digestion data show that the completely processed shale, which makes up the majority of Kvarntorpshögen, still have a high content of rare and valuable elements. Making Kvarntorpshögen itself interesting for extraction processes in the future.

CG-4 H2S adsorbent, an iron oxide based solid, has high sulfur capacity (20-25% w/w) and thus finds favor in users eyes in North America. This product, imported from CLEAN Catalysis and Purification Technologies Development Company in Shanxi Province, China, is now being used in gas processing companies in Alberta, Canada and Texas, USA. However, due to the elemental sulfur deposition on the adsorbent, the recovered sulfur capacity by regeneration is only about 1/3 as that of fresh adsorbent. This limits the adsorbent use to be once, which results in higher operating cost due to the frequent changeover and cost for landfills. The problem of sulfur deposition is also the limitation to the utilization and regeneration of other desulfurization adsorbent or catalyst. <p>This study developed a process to recover the sulfur capacity of CG-4 adsorbent by ammonia leaching to remove elemental sulfur. The leaching was conducted in a stainless steel cylindrical reactor at room temperature and a pressure higher than the vapor pressure of liquid ammonia. The leaching process does not deleteriously change the physical strength, but improve the properties of surface area, pore volume and pore size distribution. The new regeneration process is able to recover over 90% sulfur capacity in the first adsorption-regeneration cycle. The sulfur capacity recovery declined when CG-4 had been leached for more than one time. Nonetheless, even after the third time leaching, the sulfur capacity was recovered by 60%. The conditions of leaching process were optimized in a laboratory-scale experiment. <p>Additionally, the elemental sulfur collected from leaching process has 91.5% w/w purity and can likely be used as an additive to asphalt or used as a soil amendment for agricultural applications. The separation of solid wash-offs and liquid ammonia was simply fulfilled by depressurizing the leaching vessel and vaporizing the ammonia. CG-4 adsorbent is verified capable of at least three times reuses, which results in 60% reduction in disposal amount per unit H2S being treated. This not only reduces the cost in disposal to landfills but also the cost in CG-4 adsorbent and brings the revenue from the recovered elemental sulfur. The vapor ammonia is recommended to be recycled and reused by compressing it back to liquid.

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Due to the complexity of nitrogen dynamics in the soil, tracer techniques are employed to estimate the fate and transport of nitrate in agricultural fields. This study was conducted to examine effects of N fertilization and landscape position on two-dimensional redistribution of bromide in a hummocky landscape, and to identify the landscape position with the greatest potential for solute loss using a dual application of Br- and 15N. The field data on Br- transport was also simulated using the HYDRUS models. The study was carried out near Brandon, Manitoba in 2007 and 2008, using two separate plots denoted as Site-2007 and Site-2008, respectively. The field plot was delineated into three landscape positions as upper (UPP), middle (MID) and lower (LOW) slope. Each landscape position received labelled K15NO3 at the rates of 0, 90 and 135 kg N ha-1, and KBr at the rate of 200 kg Br- ha-1. Site-2007 was seeded to canola while Site-2008 had winter wheat. Soil samples were taken in the fall and the following spring and were analyzed for Br-, NO3-N, total N, and isotope N ratio. Nitrogen fertilization reduced the downward movement of Br- in the soil profile, resulting in a greater lateral movement of Br- compared to the unfertilized plots. The greatest vertical and lateral movement of Br- occurred at the LOW slope. In the dual-tracer experiment, the smallest amounts of Br-, 15N, and NO3-N were measured in the soil at the LOW slope, while the greatest amounts were at the MID slope; indicating that solute loss was: LOW > UPP > MID. In the absence of crop uptake, Br- transport was identical to that of 15N. The simulation study showed that HYDRUS-1D model was inadequate to describe solute transport in the landscape, as HYDRUS-2D/3D reproduced the field data better than HYDRUS-1D. However, the 2D model did not reflect effects of landscape position and N fertility on Br- transport. Overall, the study confirmed the “Campbell hypothesis” which states that proper N fertilization reduces nitrate leaching. The field experiment and model simulation both showed that downward movement is the main pathway of solute loss in the landscape.

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