نتایج جستجو برای: pyrite

تعداد نتایج: 3387  

2009
M Runkel

The roasting of sulphide ores and concentrates is often the first step in the production of metals or chemicals. In many processes, the production of sulphuric acid is viewed as a by-product, while in some plants production is an important economic factor. Regardless of the purpose, a pyrite roasting plant consists of mainly three plant sections: roasting, gas cleaning and sulphuric acid. With ...

Journal: :Economic Geology 1907

Journal: :international journal of nanoscience and nanotechnology 2010
s. mohammadkhani m. aghaziarati

in this research, a single-stage low-temperature hydrothermal synthesis route was successfully developed for preparation of iron disulfide. the prepared powder was characterized by x-ray diffraction (xrd) and scanning electron microscopy (sem). these analyses showed that nanoparticles were well crystallized, pyrite was the main product and the shape of crystals was nanorod. also, the influences...

2004
D. C. Golden D. W. Ming H. V. Lauer

Introduction: Although magnetite crystals in ALH84001 have received considerable attention in the literature as a potential biomarker, the sulfide component is important because the coexistence of magnetite and sulfides has also been suggested as a marker for past biogenic activity [1]. Very little research, however, has focused on the formation of sulfides in ALH84001. Early research on the su...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2010
farahnaz eghbali mohammad reza ehsani

sulfur emission from coal combustion presents many environmental problems. the techniques used to reduce the amount of sulfur in coal before combustion, include physical, chemical and biological processes.biological processes based on degradation of sulfur compounds by microorganisms offer many advantages over the conventional physical and chemical processes. the processes are performed under m...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2014
asieh akhoondi mahmoud ziarati nahid khandan

in this study, pyrite was produced by hydrothermal precipitation from the reaction between feso4 and na2s2o3 at high pressure and high temperature in a stirred reactor. the solid product was purified by means of solvent extraction to remove sulfur. powder was characterized by x-ray diffraction (xrd), scanning electron microscopy (sem) and thermal analyses. results indicated that pyrite was prod...

1999
Daniel Tao

combustion flue gas desulfurization (FGD) using lime or limestone are the primary processes employed to reduce sulfur dioxide (SO 2 ) emission from coal combustion. However, these processes generate voluminous solid wastes, i.e., pyrite and gypsum, that are usually landfilled, occupying thousands of acres of land and creating serious land and water pollution problems due to the release of acids...

2006
P. Chirita

Oxidation characteristics of natural pyrite were investigated in phosphoric acid solutions. Using hydrogen peroxide as an oxidant, the effect of particle size, reaction temperature, and hydrogen peroxide concentration were examined. The oxidation process can be described by the heterogeneous kinetic model in which the surface decomposition reaction is the rate-determining step. An activation en...

Journal: :American Journal of Science 1901

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