The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
Shruti Salwan - One of the best experts on this subject based on the ideXlab platform.
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Diverging trends in China's Fluorspar exports
Industrial minerals, 2016Co-Authors: Shruti SalwanAbstract:China's Fluorspar exports have been mixed this year with acid grade Fluorspar (acidspar) volumes increasing in contrast with metallurgical-grade Fluorspar (metspar) trades for the period Jan-May 2016, although the average value of sales fell as suppliers were forced to lower offers. The increase in exports is largely the result of oversupply within the domestic market as the slump in European and North American demand outstripped attempts to sell excess capacity into international markets. As a result, the majority of China's excess acidspar capacity was routed to India, which accounted for 43.4% of total acidspar exports. Meanwhile, aluminium fluoride (AlF[subscript]3 ) registered a more fragile performance with exports dropping by 37.5% y-o-y for the period, as overcapacity in the global aluminium industry restricted China's AlF[subscript]3 producers to operating at 40% capacity, leading to a massive drop in exports.
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South Africa targets Fluorspar's downstream market to combat slump
Industrial minerals, 2016Co-Authors: Shruti SalwanAbstract:Domestically, South Africa's uncertain regulatory framework, limited infrastructure, high labour, energy and freight costs, have all put pressure on the margins of the country's Fluorspar miners, at a time when prices for the mineral are at their lowest point since 2010. Many are struggling to compete in international markets, particularly given the emergence of low cost suppliers, principally from China, which are offering acidspar (97% CaF[subscript]2 ) material at close to $200/tonne, compared to more than $250/tonne on an FOB Durban basis. Out of the country's three Fluorspar mines - Vergenoeg, owned by Spain's Grupo Minersa; Rooiberg Stone, formerly the Buffalo Fluorspar mine, but which now produces aggregates for roads; and Witkop, owned by Vanoil Energy Ltd, another Canadian group - only Vergenoeg has been able to sustain production since 2012. While sluggish growth in the Fluorspar industry forced the closure of Solvay SA's Okorusu mine in Namibia and the suspension of processing operations at Kenya Fluorspar Co.'s Keroio Valley plant in Kenya last year, South Africa is likely to be the only acidspar producer in Africa for the foreseeable future.
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Fluorspar: : Made in China?
Industrial minerals, 2015Co-Authors: Shruti Salwan, Liz GyekyeAbstract:"In recent years, China witnessed a fast production capacity growth, especially in acid grade Fluorspar [acidspar]," the director of China-based Zhejiang Fluorspar Mine Company, Zhu Zhou Bo, told IM. "New and larger flotation mills were being built and old ones were being expanded and upgraded, thus more acidspar was being produced. In the field of metallurgical grade Fluorspar [metspar], production was also increasing with new mines being opened." From around 2003, China started to add value to its domestic Fluorspar production and restrict its exports. By 2008, China had greatly increased its exports of downstream products made from Fluorspar, particularly fluorocarbons and fluoropolymers. IHS' Will said that with China's switch from supplying the mineral to becoming a competitor in the Fluorspar-derived product market, the country had become the most important Fluorspar consumer in the world. South Africa is a significant contributor to the African Fluorspar portfolio. In 2014, it produced 240,000 tonnes Fluorspar, compared with Kenya's 80,000 tonnes and Morocco's 70,000 tonnes, according to IM 's statistics.
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Plunging Fluorspar prices weigh heavily on South African miners
Industrial minerals, 2015Co-Authors: Shruti SalwanAbstract:South Africa has the world's largest Fluorspar reserves, but its Fluorspar miners are bearing the brunt of uneconomic mining conditions, operational limitations, punitive legislation and more recently, China's attempt to liquidate its own Fluorspar inventories at record low prices. Out of the country's three Fluorspar mines, Vergenoeg - owned by Minersa; Buffalo - owned by Rigiro Stone; and Witkop - owned by Vanoil Energy Ltd, only Vergenoeg was in production in 2014. According to IM Data, prices for acidspar (97% CaF[subscript]2, dry filtercake, FOB Durban) dropped by 24% in 2014, falling from the highs of $415/tonne in Q1 2014 to $315/tonne today.
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Fluorspar miners look to divest operations
Industrial minerals, 2015Co-Authors: Shruti SalwanAbstract:Tough competition from emerging low-cost Fluorspar suppliers in Southeast Asia is making it difficult for producers elsewhere to sustain mines that cannot match these new market entrants on opex, IM learned at the Marrakech Fluorspar meeting. Supplies from this region compensate to some extent for the closure of the Witkop and Buffalo Fluorspar mines in South Africa and the potential mothballing of Okorusu in Namibia, which faces being shut down owing to poor demand for its production. Competition from China remains the main challenge for these projects
R A D Pattrick - One of the best experts on this subject based on the ideXlab platform.
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hydrothermal fluid origins in mississippi valley type ore districts combined noble gas he ar kr and halogen cl br i analysis of fluid inclusions from the illinois kentucky Fluorspar district viburnum trend and tri state districts midcontinent united
Economic Geology, 2002Co-Authors: Mark A Kendrick, R Burgess, David L Leach, R A D PattrickAbstract:Samples were selected from three of the classic Mississippi Valley-type districts in the midcontinent area of North America. The Illinois-Kentucky Fluorspar district belongs to the fluoritic subtype of Mississippi Valleytype districts, and the Ozark districts of the Viburnum Trend and Tri-State are representative of the Pb-rich and more typical Zn-rich subtypes of Mississippi Valley-type mineralization, respectively. Noble gas (Ar, Kr) and halogen (Cl, Br, I) data have been obtained simultaneously by noble gas mass spectrometry of inclusion fluids released by in vacuo crushing of irradiated fluorite, quartz, carbonate, and sphalerite samples. Additionally, He analyses have been obtained from nonirradiated fluorite from the Illinois-Kentucky Fluorspar district. Fluorite from the Illinois-Kentucky Fluorspar district has a maximum 3 He/ 4 He ratio of 0.35 Ra (where Ra = atmospheric 3 He/ 4 He ratio of 1.4 × 10 –6 ), higher than values typical of crustal fluids and confirming the presence of a minor mantle component, equal to less than 6 percent of the total He in the fluids of the Illinois-Kentucky Fluorspar district. The Br/Cl mol ratios of all the deposits are, with one exception, higher than the value of seawater (1.54 × 10 –3 ), ranging from 1.69 to 3.70 × 10 –3 , and indicating acquisition of salinity by the evaporation of seawater beyond the point of halite saturation. Late quartz from the Tri-State district contains a very minor component of halite dissolution water and has a Br/Cl mol ratio of 1.46 × 10 –3 . The I/Cl mol ratios are typical of oil field brines and are ubiquitously higher than what is attainable by the evaporation of seawater alone. I/Cl mol ratios are in the range of 6 to 270 × 10 –6 , indicating that the fluids have interacted with I-rich organic matter present in sedimentary rocks. In the Ozark districts, 40 Ar/ 36 Ar ratios vary between 320 and 345 in the Tri-State and between 350 and 420 in the Viburnum Trend. In the Illinois-Kentucky Fluorspar district 40 Ar/ 36 Ar ratios reach values of 1,200. The corresponding concentrations of 40 Arexcess ( 40 Ar not attributable to radiogenic decay of 40 K or an atmospheric source) are similarly elevated in the main-stage fluorite mineralization of the Illinois-Kentucky Fluorspar district (6.8–18.2 × 10 –4 cm 3 cm –3 H2O) relative to the Viburnum Trend and Tri-State districts (mostly 1.3–3.3 × 10 –4 cm 3 cm –3 H2O and 0.3–1.4 × 10 –4 cm 3 cm –3 H2O, respectively). Together the noble gas and halogen data indicate the existence of three brine provinces, (1) a regional TriState brine present throughout the Ozark region, (2) a Viburnum Trend brine, and (3) an Illinois-Kentucky brine. Furthermore, in the Viburnum Trend the halogen composition of main-stage dolomite is distinct from that of the main-stage sphalerite but identical to the regional hydrothermal dolomite seen in the Tri-State district. The data imply that mixing relationships in the Viburnum Trend are highly complex but are compatible with regional models in which the Tri-State brine, present throughout the Ozark region, was sourced in the Arkoma basin.
Blanpain Bart - One of the best experts on this subject based on the ideXlab platform.
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Desulphurisation and inclusion behaviour of stainless steel refining by using CaO-Al2O3 based slag at low sulphur levels
The Institute, 2014Co-Authors: Yan Pengcheng, Huang Shuigen, Van Dyck Joris, Guo Muxing, Blanpain BartAbstract:The deep desulphurisation behaviour and steel cleanliness of stainless steel refining in the low sulphur content period (below 45 ppm [%S]) by using the current lime-Fluorspar based slag and an optimized lime-alumina slag have been studied and compared. The desulphurisation effect was discussed based on the calculated sulphide capacity of slags and the equilibrated sulphur distribution ratio between the slag and steel. The sulphur evolution during the treatment was predicted with a previously developed kinetic model. The influence of slag chemistry on the compositional evolution of the steel and inclusions was discussed through thermodynamic considerations with respect to deoxidation and desulphurisation reactions. The sulphur content in the inclusions was predicted using the dissolved sulphur in the steel and their oxide chemistry. An equivalent steel cleanliness and desulphurisation effect was obtained with lime-alumina based slag as with lime-Fluorspar based slag both in laboratory and industrial tests for low sulphur content stainless refining.status: publishe
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Desulphurisation and inclusion behaviour of stainless steel refining by using CaO-Al₂O₃ based slag at low sulphur levels
'Iron and Steel Institute of Japan', 2014Co-Authors: Yan Pengcheng, Huang Shuigen, Van Dyck Joris, Guo Muxing, Blanpain BartAbstract:The deep desulphurisation behaviour and steel cleanliness of stainless steel refining in the low sulphur content period (below 45 ppm [%S]) by using the current lime-Fluorspar based slag and an optimized lime-alumina slag have been studied and compared. The desulphurisation effect was discussed based on the calculated sulphide capacity of slags and the equilibrated sulphur distribution ratio between the slag and steel. The sulphur evolution during the treatment was predicted with a previously developed kinetic model. The influence of slag chemistry on the compositional evolution of the steel and inclusions was discussed through thermodynamic considerations with respect to deoxidation and desulphurisation reactions. The sulphur content in the inclusions was predicted using the dissolved sulphur in the steel and their oxide chemistry. An equivalent steel cleanliness and desulphurisation effect was obtained with lime-alumina based slag as with lime-Fluorspar based slag both in laboratory and industrial tests for low sulphur content stainless refining.status: publishe
Mark A Kendrick - One of the best experts on this subject based on the ideXlab platform.
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hydrothermal fluid origins in mississippi valley type ore districts combined noble gas he ar kr and halogen cl br i analysis of fluid inclusions from the illinois kentucky Fluorspar district viburnum trend and tri state districts midcontinent united
Economic Geology, 2002Co-Authors: Mark A Kendrick, R Burgess, David L Leach, R A D PattrickAbstract:Samples were selected from three of the classic Mississippi Valley-type districts in the midcontinent area of North America. The Illinois-Kentucky Fluorspar district belongs to the fluoritic subtype of Mississippi Valleytype districts, and the Ozark districts of the Viburnum Trend and Tri-State are representative of the Pb-rich and more typical Zn-rich subtypes of Mississippi Valley-type mineralization, respectively. Noble gas (Ar, Kr) and halogen (Cl, Br, I) data have been obtained simultaneously by noble gas mass spectrometry of inclusion fluids released by in vacuo crushing of irradiated fluorite, quartz, carbonate, and sphalerite samples. Additionally, He analyses have been obtained from nonirradiated fluorite from the Illinois-Kentucky Fluorspar district. Fluorite from the Illinois-Kentucky Fluorspar district has a maximum 3 He/ 4 He ratio of 0.35 Ra (where Ra = atmospheric 3 He/ 4 He ratio of 1.4 × 10 –6 ), higher than values typical of crustal fluids and confirming the presence of a minor mantle component, equal to less than 6 percent of the total He in the fluids of the Illinois-Kentucky Fluorspar district. The Br/Cl mol ratios of all the deposits are, with one exception, higher than the value of seawater (1.54 × 10 –3 ), ranging from 1.69 to 3.70 × 10 –3 , and indicating acquisition of salinity by the evaporation of seawater beyond the point of halite saturation. Late quartz from the Tri-State district contains a very minor component of halite dissolution water and has a Br/Cl mol ratio of 1.46 × 10 –3 . The I/Cl mol ratios are typical of oil field brines and are ubiquitously higher than what is attainable by the evaporation of seawater alone. I/Cl mol ratios are in the range of 6 to 270 × 10 –6 , indicating that the fluids have interacted with I-rich organic matter present in sedimentary rocks. In the Ozark districts, 40 Ar/ 36 Ar ratios vary between 320 and 345 in the Tri-State and between 350 and 420 in the Viburnum Trend. In the Illinois-Kentucky Fluorspar district 40 Ar/ 36 Ar ratios reach values of 1,200. The corresponding concentrations of 40 Arexcess ( 40 Ar not attributable to radiogenic decay of 40 K or an atmospheric source) are similarly elevated in the main-stage fluorite mineralization of the Illinois-Kentucky Fluorspar district (6.8–18.2 × 10 –4 cm 3 cm –3 H2O) relative to the Viburnum Trend and Tri-State districts (mostly 1.3–3.3 × 10 –4 cm 3 cm –3 H2O and 0.3–1.4 × 10 –4 cm 3 cm –3 H2O, respectively). Together the noble gas and halogen data indicate the existence of three brine provinces, (1) a regional TriState brine present throughout the Ozark region, (2) a Viburnum Trend brine, and (3) an Illinois-Kentucky brine. Furthermore, in the Viburnum Trend the halogen composition of main-stage dolomite is distinct from that of the main-stage sphalerite but identical to the regional hydrothermal dolomite seen in the Tri-State district. The data imply that mixing relationships in the Viburnum Trend are highly complex but are compatible with regional models in which the Tri-State brine, present throughout the Ozark region, was sourced in the Arkoma basin.
Sérgio Luiz De Souza Costa - One of the best experts on this subject based on the ideXlab platform.
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use of recycled fluxes substituting Fluorspar for refining operation in a bof reactor
6th International Symposium on High-Temperature Metallurgical Processing, 2015Co-Authors: Valdeci Paula Alvarenga, Varadarajan Seshadri, Itavahn Alves Da Silva, Carlos Antônio Da Silva, Filipe Bueno Carvalho, Sérgio Luiz De Souza CostaAbstract:Use of Fluorspar in steel refining operations is one of the environmental concerns and as such reduced consumption of this material or substitution of the same is one of the objectives. Industrial runs were carried out at Aperam Steel making converter unit (Timoteo, MG, Brazil) using recycled/briquetted slag for partial or complete substitution of Fluorspar. Samples were collected from the metal bath and slag after oxygen blowing to assess dephosphorization with several combinations of recycled/briquetted slag and Fluorspar. The results showed that partial substitution of Fluorspar by BOF slag briquettes did not affect the efficiency of dephosphorization. In general average Phosphorus content was reduced to 0.010% in the case of partial substitution compared to 0.016% in the regular refining procedure with no substitution. This replacement also resulted in 40% reduction of the Fluorspar consumption in the converter
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6th International Symposium on High-Temperature Metallurgical Processing - Use of Recycled Fluxes Substituting Fluorspar for Refining Operation in a BOF Reactor
6th International Symposium on High-Temperature Metallurgical Processing, 2015Co-Authors: Valdeci Paula Alvarenga, Varadarajan Seshadri, Itavahn Alves Da Silva, Carlos Antônio Da Silva, Filipe Bueno Carvalho, Sérgio Luiz De Souza CostaAbstract:Use of Fluorspar in steel refining operations is one of the environmental concerns and as such reduced consumption of this material or substitution of the same is one of the objectives. Industrial runs were carried out at Aperam Steel making converter unit (Timoteo, MG, Brazil) using recycled/briquetted slag for partial or complete substitution of Fluorspar. Samples were collected from the metal bath and slag after oxygen blowing to assess dephosphorization with several combinations of recycled/briquetted slag and Fluorspar. The results showed that partial substitution of Fluorspar by BOF slag briquettes did not affect the efficiency of dephosphorization. In general average Phosphorus content was reduced to 0.010% in the case of partial substitution compared to 0.016% in the regular refining procedure with no substitution. This replacement also resulted in 40% reduction of the Fluorspar consumption in the converter