Sökning: "metal sulphide oxidation"

Visar resultat 6 - 10 av 24 avhandlingar innehållade orden metal sulphide oxidation.

  1. 6. Sulphide oxidation and geochemical processes in mine tailings

    Författare :Lena Alakangas; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Applied Geology; Tillämpad geologi;

    Sammanfattning : The generation of acid mine drainage (AMD) from oxidation of sulphide- bearing waste is a world wide problem, due to low pH levels and the release of metals to recipients. It is therefore important to understand the fundamental geochemical processes occurring in mine waste. LÄS MER

  3. 7. Microscopy of high temperature oxidation of iron and some stainless steels

    Författare :Torbjörn Jonsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; water vapour; sulphur dioxide; FIB; X20; stainless steel; 353MA; EDX; KCl; FIB SEM; SEM; microstructure; TEM; iron; High-temperature oxidation; in-situ ESEM;

    Sammanfattning : This thesis concerns the high temperature oxidation of iron and some stainless steels. The oxide scales, as well as the subjacent metal, were investigated using a range of electron and ion microscopy techniques, including SEM, TEM, EDX and FIB. The aim was to link the microstructural observations to the oxidation mechanisms of the materials. LÄS MER

  4. 8. Recycling process water in complex sulphide ore flotation

    Författare :Fatai Kolawole Ikumapayi; Jaako Olavi Leppinen; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mineral Processing; Mineralteknik;

    Sammanfattning : An approach to environmental sustainability and improved process economy in sulphide minerals production is recycling of process water in flotation of complex sulphide ores. However process water chemistry may be a critical issue to flotation efficiency. Process water discharged from sulphide flotation circuits are usually gypsum (CaSO4. LÄS MER

  5. 9. Fractionation of Cu and Fe isotopes in metal-rich mine sites : biotic and abiotic processes

    Författare :Nathalie Pérez Rodríguez; Magnus Land; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cu and Fe isotopes; fractionation; tailings; plants; phytoremediation; organic amendments; soil bacteria; Cu and Fe cycle; covellite; redox processes; Applied Geology; Tillämpad geologi;

    Sammanfattning : After mineral exploitation the residual grinded and milled material, rich in sulphide minerals and heavy metals, is often left exposed to the atmospheric variables. This weathered mine waste material can lead to the formation of acid mine drainage (AMD) which has negative effects to the environment. LÄS MER

  7. 10. The chemistry of flotation activation and depression of iron-containing sulphide minerals

    Författare :Xianghuai Wang; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mineralteknik; Mineral Processing;

    Sammanfattning : Thermodynamic calculations, electrochemical techniques, flotation and adsorption tests were used to study the physico-chemical principles involved in the flotation, activation and depression of the common ironcontaining sulphide minerals. Thermodynamic calculations on iron-xanthate-sulphur-water systems indicate that insoluble ferric hydroxo- xanthates can be obtained at a very low xanthate concentration in the neutral to weakly alkaline pH range, in which no liquid dixanthogen is formed. LÄS MER