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  • 1.
    Hoseinian, Fatemeh Sadat
    et al.
    Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran.
    Irannajad, Mehdi
    Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran.
    Javadi, Alireza
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Ion flotation for removal of Ni(II) and Zn(II) ions from wastewaters2015Ingår i: International Journal of Mineral Processing, ISSN 0301-7516, E-ISSN 1879-3525, Vol. 143, s. 131-137Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ion flotation was applied to Ni(II) and Zn(II) cation removal from low concentration synthetic wastewaters. Ethylhexadecyldimethylammonium bromide (EHDABr) and sodium dodecyl sulfate (SDS) were used as collectors and Dowfroth250 and methyl isobutyl carbonyl (MIBC) as frothers. The effective parameters were investigated by the experimental design performed by DX7 software. In this regard, a two-level factorial method was used, and sixteen experiments including 6-level variables were designed. In the first step, the tests were conducted in a Hallimond tube. It was concluded from test results that the optimum conditions for the removal of Ni(II) and Zn(II) ions by initial concentrations of 10. ppm were: pH = 3, SDS = 300. ppm, Dowfroth250 = 90. ppm and air flow rate = 1.8. ml/min. In the second step, optimal results from the first step were evaluated in a mechanical flotation cell. In optimal conditions, the recovery of Ni(II) and Zn(II) ions were 88% and 92%, respectively at 60. min. This study showed that the use of ion flotation is a very effective method for Ni(II) and Zn(II) ion removal from industrial wastewaters. The flotation time in achieving an optimum recovery of Zn(II) ions is shorter than that for Ni(II) ions

  • 2.
    Javadi, Alireza
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Sulphide mineral flotation: a new insight into oxidation mechanisms2013Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by sulphide minerals during grinding was investigated. It was found that pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite ((Zn,Fe)S), and galena (PbS), which are the most abundant sulphide minerals on Earth, generated H2O2 in pulp liquid during wet grinding in the presence or devoid of dissolved oxygen in water and also when the freshly ground solids are placed in water immediately after dry grinding. Pyrite generated more H2O2 than other sulphide minerals and the order of H2O2 production by the minerals found to be pyrite > chalcopyrite > sphalerite > galena. The pH of water influenced the extent of hydrogen peroxide formation where higher amounts of H2O2 are produced at highly acidic pH. The amount of H2O2 formed also increased with increasing sulphide mineral loading and grinding time due to increased surface area and its interaction with water. The sulphide surfaces are highly catalytically active due to surface defect sites and unsaturation because of broken bonds and capable of breaking down the water molecule leading to hydroxyl free radicals. Type of grinding medium on formation of hydrogen peroxide by pyrite revealed that the mild steel produced more H2O2 than stainless steel grinding medium, where Fe2+ and/or Fe3+ ions played a key role in producing higher amounts of H2O2.Furthermore, the effect of mixed sulphide minerals, i.e., pyrite–chalcopyrite, pyrite–galena, chalcopyrite–galena and sphalerite–pyrite, sphalerite–chalcopyrite and sphalerite–galena on the formation of H2O2 showed increasing H2O2 formation with increasing pyrite fraction in chalcopyrite–pyrite composition. In pyrite–sphalerite, chalcopyrite–sphalerite or galena–sphalerite mixed compositions, the increase in pyrite or chalcopyrite proportion, the concentration of H2O2 increased but with increase in galena proportion, the concentration of H2O2 decreased. Increasing pyrite proportion in pyrite–galena mixture, the concentration of H2O2 increased and also in the mixture of chalcopyrite–galena, the concentration of H2O2 increased with increasing chalcopyrite fraction. The results of H2O2 formation in pulp liquid of sulphide minerals and mixed minerals at different experimental conditions have been explained by Eh–pH diagrams of these minerals and the existence of free metal ions that are equally responsible for H2O2 formation besides surfaces catalytic activity. The results also corroborate the amount of H2O2 production with the rest potential of the sulphide minerals; higher is the rest potential more is the formation of H2O2. Most likely H2O2 is answerable for the oxidation of sulphide minerals and dissolution of non-ferrous metal sulphides in the presence of ferrous sulphide besides the galvanic interactions. This study highlights the necessity of revisiting into the electrochemical and/or galvanic interactions between the grinding medium and sulphide minerals, and interaction mechanisms between pyrite and other sulphide minerals in terms of their flotation behaviour in the context of inevitable H2O2 existence in the pulp liquid.

  • 3.
    Javadi, Alireza
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Sulphide Minerals: Surface Oxidation and Selectivity in Complex Sulphide Ore Flotation2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Metal and energy extractive industries play a strategic role in the economic development of Sweden. At the same time these industries present a major threat to the environment due to multidimensional environmental pollution produced in the course of ageing of ore processing tailings and waste rocks. In the context of valuable sulphide mineral recovery from sulphide ore, the complex chemistry of the sulphide surface reactions in a pulp, coupled with surface oxidation and instability of the adsorbed species, makes the adsorption processes and selective flotation of a given sulphide mineral from other sulphides have always been problematic and scientifically a great challenge. Invariably, the problems associated with acid mine drainage and selectivity in flotation are explained to be associated with the oxidation of metal sulphides. Although metal sulphides oxidation and galvanic effects were well known in flotation and leaching of sulphides, recent studies reveal the formation of reactive, oxidizing oxygen species and H2O2 by sulphides due to the catalytic activity of sulphide surfaces. The inherent formation of H2O2 by single and mixture of sulphide minerals during wet and dry grinding systems and in open and closed environments have been investigated. It was found that pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite ((Zn,Fe)S), and galena (PbS) generated H2O2 in pulp liquid during wet grinding in the presence and absence of dissolved oxygen in water and also when the freshly dry ground solids are placed in water immediately after grinding. Pyrite generated more H2O2 than other sulphide minerals and the order of H2O2 production by the minerals found to be pyrite > chalcopyrite > sphalerite > galena. The pH of water influenced the extent of hydrogen peroxide formation where higher amounts of H2O2 are produced at highly acidic pH. The amount of H2O2 formed also increased with increasing sulphide mineral loading and grinding time due to increased surface area and its interaction with water. The sulphide surfaces are highly catalytically active and capable of breaking down the water molecule leading to hydroxyl free radicals. Type of grinding medium on formation of hydrogen peroxide by pyrite and galena revealed that the mild steel produced more H2O2 than stainless steel grinding medium, where Fe2+ and/or Fe3+ ions played a key role in producing higher amounts of H2O2. In addition, the effect of mixed sulphide minerals, i.e., pyrite–chalcopyrite, pyrite–galena, chalcopyrite–galena and sphalerite–pyrite, sphalerite–chalcopyrite and sphalerite–galena on the formation of H2O2 showed increasing H2O2 formation with increasing the content of a nobler mineral or higher rest potential mineral in a mixed composition. The results of H2O2 formation in pulp liquid of sulphide minerals and mixed minerals at different experimental conditions have been explained by Eh–pH diagrams of these minerals and the existence of free metal ions that are equally responsible for H2O2 formation besides surfaces catalytic activity. The results also corroborate the amount of H2O2 production with the rest potential of the sulphide minerals; higher is the rest potential more is the formation of H2O2. Most likely H2O2 is answerable for the oxidation of sulphide minerals and dissolution of non-ferrous metal sulphides in the presence of ferrous sulphide besides the galvanic interactions. Studies have also been carried out to build correlation between percentage of pyrite in the concentrate, grinding conditions and concentration of OH•/H2O2 in the pulp and as well of controlling the formation of these species through known chemical means for depressing the generation of the oxidant. Flotation tests using a complex sulphide ore with the same reagent scheme that is being used at Boliden concentrator but with the addition of collector and depressant during grinding stage have been performed to judge the beneficial or detrimental role of H2O2 on the selective flotation of sulphides. The results demonstrate that the selectivity of metal sulphides against pyrite increases with increasing generation of H2O2 in the pulp liquid. This study highlights the necessity of revisiting into the electrochemical and/or galvanic interactions between the grinding medium and sulphide minerals, and interaction mechanisms between pyrite and other sulphide minerals in terms of their flotation behaviour, leaching and environmental degradation in the context of inevitable H2O2 existence in the pulp liquid.

  • 4.
    Javadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    A New Insight Into Oxidation Mechanisms of Sulphide Minerals2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by sulphide minerals during grinding was examined. It was found that pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite ((Zn, Fe) S), and galena (PbS) generated H2O2 in pulp liquid during wet grinding and also when the freshly ground solids are placed in water immediately after dry grinding. Pyrite produced more H2O2 than other minerals and the order of H2O2 production by the minerals was found to be pyrite > chalcopyrite > sphalerite > galena. The pH of the water influenced the extent of hydrogen peroxide formation with greater amounts of H2O2 produced at highly acidic pH. Furthermore, the effect of mixed sulphide minerals, i.e., pyrite–chalcopyrite, pyrite–galena, chalcopyrite–galena and sphalerite–pyrite, sphalerite–chalcopyrite and sphalerite-galena on the formation of H2O2 showed increasing H2O2 formation with increasing pyrite fraction. There is clear correlation of the amount of H2O2 production with the rest potential of the sulphide minerals; the greater the rest potential of a mineral the greater the formation of H2O2. This study highlights the necessity of revisiting the electrochemical and/or galvanic interactions between sulphide minerals, and interaction mechanisms between pyrite and other sulphide minerals in terms of their flotation behaviour in the context of inevitable H2O2 existence in the pulp liquid

  • 5.
    Javadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Effect of grinding environment on galena flotation2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The participation of H2O2 in oxidation of the galena mineral and as a result in decreasing of the concentrate recovery of galena mineral has not yet been shown. In this study the effect of two types of grinding media in wet and dry grinding on the formation of hydrogen peroxide and galena flotation was investigated. Laboratory stainless steel ball mill (Model 2VS, CAPCO Test Equipment, Suffolk, UK) was used for grinding galena with mild steel and stainless steel media. Galena ground with mild steel generated more hydrogen peroxide than galena ground with stainless steel media. Galena ground with mild steel has a lower galena recovery than galena ground with stainless steel media. Solutions of 2, 9-dimethyl-1, 10-phenanthroline (DMP) were used for estimating H2O2 amount in pulp liquid with DU® Series 700 UV/Vis Scanning Spectrophotometer. This study highlights the necessity of relooking into galvanic interaction mechanisms between the grinding medium and galena in terms of its flotation behavior.

  • 6.
    Javadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Formation of hydrogen peroxide by chalcopyrite and its influence on flotation2013Ingår i: Minerals & metallurgical processing, ISSN 0747-9182, Vol. 30, nr 4, s. 212-219Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by chalcopyrite (CuFeS2), which is a copper iron sulfide mineral, during grinding, was investigated. It was observed that chalcopyrite generated H2O2 in pulp liquid during wet grinding and also the solids when placed in water immediately after dry grinding. The generation of H2O2 in either wet or dry grinding was thought to be due to a reaction between chalcopyrite and water where the mineral surface is catalytically active in producing •OH free radicals by breaking down the water molecule. Effect of pH in grinding medium or water pH in which solids are added immediately after dry grinding showed lower the pH value more was the H2O2 generation. When chalcopyrite and pyrite are mixed in different proportions, the formation of H2O2 was seen to increase with increasing pyrite fraction in the mixed composition. The results of H2O2 formation in pulp liquid of chalcopyrite and together with pyrite at different experimental conditions have been explained by Eh-pH diagrams of these minerals. This study highlights the necessity of revisiting the electrochemical and/or galvanic interaction mechanisms between the chalcopyrite and pyrite in terms of their flotation behaviour.

  • 7.
    Javadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Formation of hydrogen peroxide by chalcopyrite and pyrite2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by chalcopyrite (CuFeS2), which is a copper iron sulfide mineral, during grinding, was investigated. It was observed that chalcopyrite and pyrite generated H2O2 in pulp liquid during wet grinding and also the solids when placed in water immediately after dry grinding. The generation of H2O2 in either wet or dry grinding was thought to be due to a reaction between chalcopyrite and water where the mineral surface is catalytically active in producing •OH free radicals by breaking down the water molecule. When chalcopyrite and pyrite are mixed in different proportions, the formation of H2O2 was seen to increase with increasing pyrite fraction in the mixed composition. The results of H2O2 formation in pulp liquid of chalcopyrite and together with pyrite at different experimental conditions have been explained by Eh-pH diagrams of these minerals. This study highlights the necessity of revisiting the electrochemical and/or galvanic interaction mechanisms between the chalcopyrite and pyrite.

  • 8.
    Javadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Formation of hydrogen peroxide by galena and its influence on flotation2014Ingår i: Advanced Powder Technology, ISSN 0921-8831, E-ISSN 1568-5527, Vol. 25, nr 2, s. 832-839Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, during the grinding of galena (PbS) was examined. It was observed that galena generated H2O2 in pulp liquid during wet grinding and also when the freshly ground solids were placed in water immediately after dry grinding. The generation of H2O2 during either wet or dry grinding was thought to be due to a reaction between galena and water, when the mineral surface is catalytically active, to produce OH• free radicals by breaking down the water molecule. It was also shown that galena could generate H2O2 in the presence or absence of dissolved oxygen in water. The concentration of H2O2 formed increased with decreasing pH. The effects of using mixtures of pyrite or chalcopyrite with galena were also investigated. In pyrite-galena mixture, the formation of H2O2 increased with an increase in the proportion of pyrite. This was also the case with an increase in the fraction of chalcopyrite in chalcopyrite-galena mixtures. The oxidation or dissolution of one specific mineral rather than the other in a mixture can be explained better by considering the extent of H2O2 formation rather than galvanic interactions. It appears that H2O2 plays a greater role in the oxidation of sulphides or in aiding the extensively reported galvanic interactions. This study highlights the necessity of further study of electrochemical and/or galvanic interaction mechanisms between pyrite and galena or chalcopyrite and galena in terms of their flotation behaviour.

  • 9.
    Javadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Formation of hydrogen peroxide by sphalerite2013Ingår i: International Journal of Mineral Processing, ISSN 0301-7516, E-ISSN 1879-3525, Vol. 125, s. 78-85Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by sphalerite ((Zn, Fe) S) was examined during its grinding process. It was observed that sphalerite generated H2O2 in pulp liquid during wet grinding and also when the freshly ground solids placed in water immediately after dry grinding. The generation of H2O2 in either wet or dry grinding was thought to be due to a reaction between sphalerite and water where the mineral surface is catalytically active to produce OH• free radicals by breaking down the water molecule. Effect of pH on the formation of H2O2 by sphalerite was shown that the acidic pH generated more H2O2. Mixtures of pyrite, chalcopyrite and galena with sphalerite on the formation of H2O2 were also probed. It was shown that the concentration of H2O2 increases with increasing pyrite or chalcopyrite fraction in pyrite–sphalerite, chalcopyrite–sphalerite mixtures but with an increase in galena proportion, the concentration of H2O2 decreased in galena–sphalerite mixture. The oxidation or dissolution of one mineral than the other in a mixture can be explained better with the extent of H2O2 formation in the pulp liquid than galvanic interactions. It is clear of the greater role of H2O2 in the oxidation of sulphides or aiding the extensively reported galvanic interactions since the amount of H2O2 generated with a specific mineral followed the rest potential series. This study highlights the necessity of further investigations into the role of H2O2 in electrochemical and/or galvanic interaction mechanisms between pyrite, chalcopyrite and galena with sphalerite.

  • 10.
    Javadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Formation of hydrogen peroxide by sulphide minerals2014Ingår i: Hydrometallurgy, ISSN 0304-386X, E-ISSN 1879-1158, Vol. 141, s. 82-88Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by sulphide minerals during grinding was investigated. It was found that pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite ((Zn,Fe)S), and galena (PbS), which are the most abundant sulphide minerals on Earth, generated H2O2 in pulp liquid during wet grinding in the presence of dissolved oxygen in water and also when the solids are placed in water immediately after dry grinding. Pyrite generated more H2O2 than other minerals and the order of H2O2 production by the minerals found to be pyrite > chalcopyrite > sphalerite > galena. The pH of water influenced the extent of hydrogen peroxide formation where higher amounts of H2O2 are produced at highly acidic pH. Furthermore, the effect of mixed sulphide minerals, i.e., pyrite–chalcopyrite, pyrite–galena, chalcopyrite–galena and sphalerite–pyrite, sphalerite–chalcopyrite and sphalerite–galena on the formation of H2O2 showed increasing H2O2 formation with increasing pyrite fraction in chalcopyrite–pyrite, galena–pyrite and sphalerite–pyrite compositions. The results also corroborate the amount of H2O2 production with the rest potential of the sulphide minerals; higher the rest potential of a sulphide mineral, formation of H2O2 is more. Most likely H2O2 is responsible for the oxidation of sulphide minerals and dissolution of non-ferrous metal sulphides in the presence of ferrous sulphide in addition to galvanic interactions. This study highlights the necessity of revisiting the electrochemical and/or galvanic interactions between pyrite and other sulphide minerals in terms of their flotation and leaching behaviour in the context of inevitable H2O2 existence in the pulp liquid.

  • 11.
    Javadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Sulphide mineral flotation: a new insight into oxidation mechanisms2013Ingår i: XIII International Seminar on Mineral Processing Technology: CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, Odisha 751013, India / [ed] Alok Tripathy, Madras: Indian Institute of Technology Madras, 2013, s. 169-182Konferensbidrag (Refereegranskat)
    Abstract [en]

    The formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by sulphide minerals during grinding was investigated. It was found that pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite (ZnS), and galena (PbS), which are the most abundant sulphide minerals on Earth, generated H2O2 in pulp liquid during wet grinding in the presence and absence of dissolved oxygen in water and also when the freshly ground solids were placed in water immediately after dry grinding. Pyrite generated more H2O2 than the other sulphide minerals and the order of H2O2 production by the minerals was found to be pyrite > chalcopyrite >sphalerite> galena. The pH of water influenced the extent of hydrogen peroxide formation where higher amounts of H2O2 were produced at highly acidic pH. The amount of H2O2 formed also increased with increasing sulphide mineral loading and grinding time due to increased surface area and its interaction with water.The sulphide surfaces are highly catalytically active due to surface defect sites and unsaturation because of broken bonds and capable of breaking down the water molecule leading to hydroxyl free radicals. The type of grinding medium on formation of hydrogen peroxide by pyrite revealed that the mild steel produced more H2O2 than stainless steel grinding medium, where Fe2+ and/or Fe3+ ions played a key role in producing higher amounts of H2O2.Furthermore, the effect of mixed sulphide minerals, i.e., pyrite–chalcopyrite, pyrite–galena, chalcopyrite–galena and sphalerite–pyrite, sphalerite–chalcopyrite and sphalerite–galena on the formation of H2O2 showed increasing H2O2 formation with increasing pyrite fraction in chalcopyrite–pyrite composition. In pyrite–sphalerite, chalcopyrite–sphalerite or galena– sphalerite mixed compositions, with the increase in pyrite or chalcopyrite proportion, the concentration of H2O2 increased but with increase in galena proportion, the concentration of H2O2 decreased. By increasing the pyrite proportion in pyrite–galena mixture, the concentration of H2O2 increased. Similarly, in the mixture of chalcopyrite–galena, the concentration of H2O2 increased with increasing chalcopyrite fraction. The results of H2O2formation in pulp liquid of individual sulphide minerals and in combination at different experimental conditions have been explained by Eh–pH diagrams of these minerals and the existence of free metal ions that are equally responsible for H2O2 formation besides the catalytic activity of surfaces. The results of the amount of H2O2 production also corroborate with the rest potential of the sulphide minerals; higher the rest potential more is the formation of H2O2. Most likely H2O2 is responsible for the oxidation of sulphide minerals and dissolution of non-ferrous metal sulphides in the presence of ferrous sulphide besides the galvanic interactions.This study highlights the necessity of revisiting the electrochemical and/or galvanic interactions between the grinding medium and sulphide minerals, and interaction mechanisms between pyrite and other sulphide minerals in terms of their flotation behaviour in the context of the inevitable existence of H2O2 in the pulp liquid.

  • 12.
    Kota, Hanumantha Rao
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Javadi, Alireza
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Karlkvist, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Patra, Anuttam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Vilinska, Annamaria
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Chernyshova, IV
    Revisiting sulphide mineral (bio) processing: a few priorities and directions2013Ingår i: Powder Metallurgy & Mining, ISSN 2168-9806, Vol. 2, nr 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Large efforts are being made to streamline the conventional (chemical and physical) technological schemes of ore processing, remediation and environmental protection towards reducing overall costs, limiting the use of dangerous substances, decreasing waste streams and improving waste disposal and recycling practice. Hitherto, search for such innovations has been performed mainly empirically and there is an urgent need to shift these technologies to be more innovative and effective. Alternative biotechnological solutions and solutions mimicking natural processes are also being proposed. However, except for bioleaching, practical exploitation of the biotechnological potential in extractive industries and accompanying environmental protection measures remains far from feasibility. Understanding of the fundamental concepts of aquatic chemistry of minerals–selective adsorption and selective redox reactions at mineral– bacteria–solution interfaces, impact innovating conventional and bio-flotation, as well as (bio) remediation/detoxification of mineral and chemical wastes are necessary. Molecular-level knowledge and coherent understanding of minerals contacted with aqueous solutions is required that underlie great opportunities in controlling abiotic and biotic mineral– solution interfaces towards the grand challenge of tomorrow’s science and mineral processing technology

  • 13.
    Kota, Hanumantha Rao
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Javadi, Alireza
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Karlkvist, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Patra, Anuttam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Vilinska, Annamaria
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Chernyshova, I.V.
    Revisiting sulphide mineral (bio) processing: a few priorities and directions2013Ingår i: XV Balkan Mineral Processing Congress, 12-16 June 2013, Sozopol, Bulgaria, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Large efforts are being made to streamline the conventional (chemical and physical) technological schemes of ore processing, remediation and environmental protection towards reducing overall costs, limiting the use of dangerous substances, decreasing waste streams and improving waste disposal and recycling practice. Hitherto, search for such innovations has been performed mainly empirically and there is an urgent need to shift these technologies to be more innovative and effective. Alternative biotechnological solutions and solutions mimicking natural processes are also being proposed. However, except for bioleaching, practical exploitation of the biotechnological potential in extractive industries and accompanying environmental protection measures remains far from feasibility.Understanding of the fundamental concepts of aquatic chemistry of minerals–selective adsorption and selective redox reactions at mineral–bacteria–solution interfaces, impact innovating conventional and bio-flotation, as well as (bio)remediation/detoxification of mineral and chemical wastes. Molecular-level knowledge and coherent understanding of minerals contacted with aqueous solutions is required that underlie great opportunities in controlling abiotic and biotic mineral–solution interfaces towards the grand challenge of tomorrow’s science and mineral processing technology.

  • 14.
    Nooshabadi, Alireza Javadi
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Larsson, Anna-Carin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Formation of hydrogen peroxide by pyrite and its influence on flotation2013Ingår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 49, s. 128-134Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by pyrite (FeS2), the most abundant metal sulphide on Earth, during grinding was investigated. It was found that pyrite generated H2O2 in pulp liquid during wet grinding and also the solids when placed in water immediately after dry grinding. Type of grinding medium on formation of hydrogen peroxide revealed that the mild steel produced more H2O2 than stainless steel grinding medium, where Fe2+ and/or Fe3+ ions played a key role in producing higher amounts of H2O2. The effect of grinding atmosphere of air and N2 gas showed that nitrogen environment free from oxygen generated more H2O2 than air atmosphere suggesting that the oxygen in hydrogen peroxide is derived from water molecules. In addition, the solids after dry grinding producing more H2O2 than wet grinding indicate the role of pyrite surface or its catalytic activity in producing H2O2 from water. This study highlights the necessity of relooking into the electrochemical and/or galvanic interaction mechanisms between the grinding medium and pyrite in terms of its flotation behaviour.

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