Deposit potential and distribution of cobalt and nickel in the sludge of chromite placer mining process at Nui Nua ultramafic massif area, Thanh Hoa province, Vietnam

The concentrations of cobalt, nickel, and silver, determined by neutron activation analysis, are systematically lower in the east Pacific sector of the Antarctic Ocean relative to other oceanic areas. This is indicated by two traverses between 70°S and 54°S at 115°W and about 90°W. Transport of cobalt, nickel, and silver from the Pacific Ocean to the Atlantic Ocean via the Drake Passage is thus minimal. Calculations based on the silver concentration in Pacific and antarctic waters and antarctic sediments indicate that a flow rate 1% of that predicted for the transport of Pacific deep water is consistent with the data. The dissolving of glacial flour may be responsible for the relatively high concentrations of cobalt and nickel encountered at the closest approach to the antarctic continent.

The distribution of gallium, germanium, cobalt, chromium, and copper in iron and stony-iron meteorites in relation to nickel content and structure

ABSTRACTThe main aim of the study was to understand the present status of cobalt in different agro-climatic zones. The soil samples were collected from different locations and topo-sequences of three agro-climatic zones of Jharkhand, India, viz. zone-IV (Baliapur, Jharia, and Dhanbad), zone-V (Bagru, Pakharpat, Kisko, and Lohardaga), and zone-VI (Moshabani, Jadugonda, and Chandil). The soil samples were analyzed in a laboratory to estimate the total cobalt and Diethylene-triamine pentaacetic acid (DTPA) extractable cobalt. Results show mean concentration of DTPA extractable cobalt in zones-IV, V, and VI have been determined as 0.65, 0.5, and 1.03 mg kg−1, whereas the mean total cobalt content in different agro-climatic zones was 109.17, 107.58, and 102.58 mg kg−1, respectively. The work highlights the higher amount of DTPA-extractable and the total content of cobalt was observed in lowland against the different topo-sequences. Further, the results of multiple regression equations have revealed that the distribution of extractable cobalt is primarily controlled by pH, clay, and organic carbon. Whereas, organic carbon controls the distribution of total cobalt content hence, the organic carbon plays a critical role in the distribution of cobalt in the soil.

In the Saguenay fjord sediments, cobalt (Co) concentrations vary between 5 and 20 ppm, nickel (Ni) concentrations between 7 and 36 ppm, chromium (Cr) concentrations from 33 to 70 ppm, and vanadium (V) concentrations from 67 to 149 ppm in relation to texture and location. The highest concentrations are found in the fine-grained sediments from the upper part of the fjord and the lowest concentrations occur in the sandy sediments near the mouth of the fjord. On the average, the fjord's muds are neither greatly enriched nor depleted in Co, Ni, Cr, and V when compared to muds from the St. Lawrence estuary and the open Gulf of St. Lawrence.Acetic acid extractions indicate that 8 to 25% of the total Co, 11 to 29% of the total Ni, 2 to 9% of the total Cr, and 5 to 23% of the total V are contributed by the non-detrital fraction and may be available to the biota in the fjord. Non-detrital Co, Ni, Cr, and V appear to have been removed from solution by adsorption onto fine-grained inorganic particles and their distribution controlled by the sedimentation pattern. Non-delrital Cr, V, and Ni are also associated with Mn and Fe oxides, which are present as grain coatings. Most of the Co, Ni, Cr, and V in the detrital fraction, which accounts for 71 to 98% of the total elemental concentrations are found in sulphide, oxide, and ferromagnesian minerals. These minerals accumulate at the same rate as other detrital sedimentary material in response to the present depositional conditions.The discharge of industrial waste has not resulted in an increase in the concentrations of Co, Ni, Cr, and V in the sediments above their natural levels.

Macrophytes react to changes in the quality of the environment in which they live (water/sediment), and they are good bioindicators of surface water conditions. In the present study, the content of the metals cobalt (Co) and nickel (Ni) was determined in the sediment, the water, and different organs of macrophytes from six localities around Lake Skadar, across four different seasons of year. The aquatic macrophytes that have been used as bioindicator species in this study are Phragmites australis (an emerged species), Ceratophyllum demersum (a submerged species), and Lemna minor (a floating species). The aim of this study was to determine the distribution of metals in macrophyte tissues and also to discover the degree of bioaccumulation of the investigated metals, depending both on the location and on the season. The content of Co and Ni in the examined parts of the macrophytes was in the range of 0.04-8.78 and 0.30-28.5ppm, respectively. The greatest content of the investigated metal in the organs of P. australis and C. demersum was recorded at the beginning of and during the growing season. Greater concentrations of metals in the tissue of L. minor were observed at the end of the growing season.

The distribution of nickel, cobalt, gallium, palladium and gold in iron meteorites

Effects of cobalt on plants

Nickel and cobalt distribution in the laterites of the Lomié region, south-east Cameroon

The geobiochemistry of cobalt

An adequate supply of Co in pasture is important to the health of grazing animals. Bio-availability of Co in soils is largely depended upon its distribution among solid-phase fractions. Distribution of cobalt in six arid-zone soils and its redistribution among the solid-phase fractions during long-term saturated paste incubation were studied. Cobalt was fractionated by a selective sequential dissolution procedure into six empirically defined fractions. Concentrations of total Co and Mn or Fe, and Co and Mn fractionation pattern were strongly correlated in the soils. During saturated incubation, Co in soils was redistributed mainly from the Mn oxide bound, and to some extent, Fe oxide bound and organic matter bound fractions into the carbonate bound fraction. During saturated incubation, significant correlations were found between concentrations of Co and Mn in the Mn oxide bound, Fe oxide bound and carbonate bound fractions. Also, significant correlations between concentrations of Co and Fe in the Fe oxide bound fraction were present. However, a negative correlation between concentrations of Co and Fe in the Mn oxide bound fraction was observed. The rates of redistribution of Co between these solid-phase components were initially high: major changes occurred in the first 3 days in the sandy soil and the first 18 days in the loessial soil. Afterwards, the rates of change slowed but changes in redistribution continued during the rest of the study period of one year.

The impact of trace elements from the Iron Mountain Superfund site on the Sacramento River and selected tributaries is examined. The concentration and distribution of many trace elements-including aluminum, arsenic, boron, barium, beryllium, bismuth, cadmium, cerium, cobalt, chromium, cesium, copper, dysprosium, erbium, europium, iron, gadolinium, holmium, potassium, lanthanum, lithium, lutetium, manganese, molybdenum, neodymium, nickel, lead, praseodymium, rubidium, rhenium, antimony, selenium, samarium, strontium, terbium, thallium, thulium, uranium, vanadium, tungsten, yttrium, ytterbium, zinc, and zirconium-were measured using a combination of inductively coupled plasma-mass spectrometry and inductively coupled plasma-atomic emission spectrometry. Samples were collected using ultraclean techniques at selected sites in tributaries and the Sacramento River from below Shasta Dam to Freeport, California, at six separate time periods from mid-1996 to mid-1997. Trace-element concentrations in dissolved (ultrafiltered [0.005-μm pore size]) and colloidal material, isolated at each site from large volume samples, are reported. For example, dissolved Zn ranged from 900μg/L at Spring Creek (Iron Mountain acid mine drainage into Keswick Reservoir) to 0.65μg/L at the Freeport site on the Sacramento River. Zn associated with colloidal material ranged from 4.3μg/L (colloid-equivalent concentration) in Spring Creek to 21.8μg/L at the Colusa site on the Sacramento River. Virtually all of the trace elements exist in Spring Creek in the dissolved form. On entering Keswick Reservoir, the metals are at least partially converted by precipitation or adsorption to the particulate phase. Despite this observation, few of the elements are removed by settling; instead the majority is transported, associated with colloids, downriver, at least to the Bend Bridge site, which is 67km from Keswick Dam. Most trace elements are strongly associated with the colloid phase going downriver under both low- and high-flow conditions.

The distribution of zinc, manganese, copper, cobalt, and nickel in Andosols was investigated. Sixty nine soil samples were collected from different horizons of an Andosols profile in Miyakonojo Basin in south Kyushu, Japan, The total contents of heavy metals were determined by digestion and four extraction solutions, 1 M NH4Ac (ammonium acetate) pH 4.5, 0.1 M HCl, 0.01 M EDTA (ethylenediaminetetraacetic acid) pH 6.5, and 0.005 M DTPA (diethylenetri-aminepentaacetic acid) pH 7.3 were used to determine the contents of available Zn, Mn, Cu, Co, and Ni in Andosols in relation to the organic carbon content. The results of the extraction analysis showed that by the use of 0.1 M H Cl high value of extracted heavy metals in the upper layers of the humus horizons were obtained while EDTA extraction yielded a large amount of the above mentioned metals in the high humus horizons. The extractable heavy metals contents were high and these metals closely related to the organic carbon content mostly in the humus horizons in the profile. Where, biocycling process may play an important role in the concentration of heavy metals. Based on the study, it was found that the total content of Zn increased towards the C horizons or pumice layers in the soil profile. Such a trend was also found in the case of the Mn content. While the Cu content in the humus horizons was much higher in the upper part of each humus horizon. According to this study the distribution of heavy metals, Cu (organic matter complexes) in the Andosols profile was more stable than that of Zn (organic matter complexes) in soils. It was shown that Zn in the surface humus horizon was enriched but that some amount was leached under buried conditions. The same phenomenon was also observed in the distribution of Mn in the profile. The movement of Co and Ni in the soil profile was limited, as evidenced by the sharp reduction in the concentrations of these two metals in buried soils. Hence, it is concluded that the distribution of Zn, Mn, Cu, Co, and Ni was considerably higher in the humus horizons of the Andosols profiles.

Abstract. Cobalt is the scarcest of metallic micronutrients and displays a complex biogeochemical cycle. This study examines the distribution, chemical speciation, and biogeochemistry of dissolved cobalt during the US North Atlantic GEOTRACES transect expeditions (GA03/3_e), which took place in the fall of 2010 and 2011. Two major subsurface sources of cobalt to the North Atlantic were identified. The more prominent of the two was a large plume of cobalt emanating from the African coast off the eastern tropical North Atlantic coincident with the oxygen minimum zone (OMZ) likely due to reductive dissolution, biouptake and remineralization, and aeolian dust deposition. The occurrence of this plume in an OMZ with oxygen above suboxic levels implies a high threshold for persistence of dissolved cobalt plumes. The other major subsurface source came from Upper Labrador Seawater, which may carry high cobalt concentrations due to the interaction of this water mass with resuspended sediment at the western margin or from transport further upstream. Minor sources of cobalt came from dust, coastal surface waters and hydrothermal systems along the Mid-Atlantic Ridge. The full depth section of cobalt chemical speciation revealed near-complete complexation in surface waters, even within regions of high dust deposition. However, labile cobalt observed below the euphotic zone demonstrated that strong cobalt-binding ligands were not present in excess of the total cobalt concentration there, implying that mesopelagic labile cobalt was sourced from the remineralization of sinking organic matter. In the upper water column, correlations were observed between total cobalt and phosphate, and between labile cobalt and phosphate, demonstrating a strong biological influence on cobalt cycling. Along the western margin off the North American coast, this correlation with phosphate was no longer observed and instead a relationship between cobalt and salinity was observed, reflecting the importance of coastal input processes on cobalt distributions. In deep waters, both total and labile cobalt concentrations were lower than in intermediate depth waters, demonstrating that scavenging may remove labile cobalt from the water column. Total and labile cobalt distributions were also compared to a previously published South Atlantic GEOTRACES-compliant zonal transect (CoFeMUG, GAc01) to discern regional biogeochemical differences. Together, these Atlantic sectional studies highlight the dynamic ecological stoichiometry of total and labile cobalt. As increasing anthropogenic use and subsequent release of cobalt poses the potential to overpower natural cobalt signals in the oceans, it is more important than ever to establish a baseline understanding of cobalt distributions in the ocean.

Polymetallic nodules and nickel laterite ores are composed of various valuable metals and have similar nickel concentration, which makes them ideal alternatives for industries seeking to meet the increasing demand for nickel resources. The extraction process of polymetallic nodules can utilize the well-established nickel laterite treatment process without the need for developing new processes and thus, save capital costs. Herein, to efficiently extract nickel from these resources, high-temperature carbothermic reduction and sulfurization were investigated by optimizing the slag and matte systems. FactSage, a thermodynamic software was used to predict the slag system’s liquidus temperature and the formation of nickel matte. It was found that nickel matte formation was not dependent on CaSO4 addition whereas the nickel concentration in matte decreased with an increasing amount of the sulfiding agent FeS. Furthermore, the addition of a reductant significantly affected the concentration of nickel in the matte. A nickel concentration of ≥30 wt% and iron concentration of ≤40 wt% in matte were achieved by adding 0.5 wt% and 3 wt% carbon to nickel laterite ores and polymetallic nodules, respectively. Furthermore, replacing the sulfiding agent FeS with CaSO4 during the smelting of polymetallic nodules decreased the iron concentration in matte ≤15 wt% and increased the nickel concentration ≥50 wt%. Thus, this study confirmed the possibility of matte formation with high nickel concentration and low iron content by utilizing alternative nickel resources at 1350–1450°C.

The results of a study of copper, nickel, cobalt, platinum, palladium, gold, and rhodium distribution in basic ore-forming sulfide minerals (chalcopyrite and pyrrhotites) as well as in the silicate portion of the host rocks of the Noril'sk deposit, are given. Interrelations between metals in different sulfide minerals and silicates are characterized. It has been established that palladium, platinum, and gold are concentrated in chalcopyrite while cobalt and rhodium are concentrated in pyrrhotite. The cobalt and precious metal content in sulfides grows with the increase of their nickel content. The relative content, however, of all these elements estimated for 1% of nickel is different in chalcopyrites and pyrrhotites. The former show a high platinum, palladium, and gold content and the latter--cobalt and rhodium. Ratios of these elements in sulfides and silicates are different. The relative platinum content increases in silicates due to a considerably greater content of mineralized platinum. Both nickel and cobalt form silicate compounds the latter to a much greater extent than the former. The relative cobalt content is therefore higher in silicates than in sulfides. In descending order, the element concentrations in sulfides range as follows: copper, nickel, palladium, gold, cobalt, platinum. — Auth. English Summ.