Browsing by Subject "birch"

Aim of this study is to develop biogeochemical exploration methods for cobalt. Several different samples were collected from study area, analyzed, and compared to each other. This study took place at Rautio village at North Ostrobothnia and more accurately over the Jouhineva mineralization. Jouhineva is well-known high-grade cobalt-copper-gold mineralization. Elements examined in this study are cobalt, copper, arsenic, zinc, selenium, and cadmium. Samples were collected from three different study profiles from the area. From these three profiles samples collected are: soil, pine, lingonberry, birch, rowan, and juniper. Water samples were collected around the study area from every location possible. Soil samples were analyzed with four different methods: Ionic leaching, aqua regia, weak leaching and pXRF. Ionic leaching and aqua regia had both elevated concentrations of cobalt, but in different locations depending on study profile. Ionic leaching detects rising ions from the ore and therefore elevated concentrations are found at different locations compared to aqua regia. Aqua regia results proved how different orientation of study profile, direction of the ore and glacial flow can affect to the anomalies of elemental concentration. Profile-2 was oriented differently to ore and glacial flow than Profile-1, and therefore elevated concentrations of cobalt and copper were not drifted away from the ore on Profile-2 like they were on Profile-1. Aqua regia and pXRF have very similar copper, arsenic and zinc results. Pine and lingonberry turn out to be the most promising plant species applied for cobalt exploration, and rowan appears to be most suitable for copper exploration. Lower detection limit could significantly improve pine analyses as exploration method and more extensive sampling could remove some of the uncertainties about the method. Lingonberry samples have elevated concentration of copper and arsenic. Birch and juniper produced somewhat unclear results. Despite this, cobalt and copper concentrations in birch leaves were elevated when compared to concentrations found in other studies. In addition to this birch is suitable for arsenic exploration. Juniper had elevated copper concentration in the study area compared to other studies. Water samples collected from the Jouhineva area yielded concentrations of cobalt, copper and arsenic that were above the average concentration in the Kalajoki area waters. Copper and arsenic were above the average concentration of the Kalajoki area in every sample collected from the study area. Cobalt was above the average concentration in all samples that were not collected directly from the pond formed in the old test mine. Zinc concentration was below the average limit in all samples collected from the area. Zinc concentration in the water samples collected from the pond is significantly lower compared to the other samples collected from the area.

Carbonization is thermochemical conversion, where biomass is thermally degraded in the absence of oxygen. Solid char, pyrolysis oil and non-condensable gases are produced from the biomass. Torrefaction is early phase of the carbonization in temperatures of 220–300 °C. Torrefied wood is promising as a renewable fuel for industrial use in coal co-combustion and gasification-combustion. Torrefaction and carbonization increase the higher heating value and fuel properties of wood compared to untreated wood. There’s a lack of knowledge in torrefaction and carbonization effects to higher heating value, carbon content and turn from endothermic to exothermic reaction of conifer zone wood species. Raw material was stemwood of birch (Betula pubescens) and pine (Pinus sylvestris) including bark. Trees were harvested from the Helsinki district and chipped, particle size 16 ≤ 8 mm. Samples were torrefied and carbonized at 250, 300, 350, 400 and 450 ˚C without nitrogen flow. Carbon content (%), higher heating value (MJ/kg), mass yield (%) and turn of endothermic to exothermic reaction were inspected. Carbon content of untreated birch and pine increased from 47 % to 82 % (at 450 ˚C). Higher heating value exceeded 26 MJ/kg at 300 ˚C and 28 MJ/kg at 400 ˚C, reaching bituminous coal’s values. Mass yield declined to 45–54 % of the initial mass at 300 °C. In low temperature, gradual exothermic peak was observable. In higher temperatures peak was evident. Carbonization and torrefaction improved the higher heating value and carbon content of wood but decreased the solid char yield.