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Year 2001 No 3

Kupka D., Škvarla J.
KINETICS OF CHEMICAL OXIDATION OF FERROUS IRON BY OXYGEN IN ACID SULFATE SOLUTIONS
Abstract
Ferric sulfate is one of the most important reagent used in hydrometallurgy for dissolution of metal sulphides. The leaching of minerals depends upon the re-oxidation of Fe2+ to Fe3+ and recycling of the reagent. The oxidation of ferrous iron plays an important role in either commercial leaching operations or natural weathering of sulphide minerals. Iron oxidation rates observed in natural acid mine drainage highly exceed the rates found in experiments performed under sterile conditions in laboratory. This is due to the catalytic action of iron oxidizing bacteria which are usually present in such natural environments. This work presents the kinetic study of chemical (abiotic) oxidation of ferrous sulfate to ferric sulfate with molecular oxygen. For an initial ferrous iron concentration in the range of 0.08-0.64 M, temperatures in the range of 288-323 K and pH ? 2, the Fe2+ oxidation rate was found to be well described by the rate expression -dFe2+/dt = 1.26 ? 107 [Fe2+]2 PO2 exp (-72000/RT).

Keywords: Fe|oxidation|ferrous|ferric|sulfate|kinetics|oxygen|acid solutions|acid mine drainage|
No 3 (2001), p. 243-248
  mag01.pdf (70 kB)
mag01_eng.txt (1 kB)  

Kupka D., Škvarla J.
OXIDATION OF FERROUS SULFATE BY GROWING CULTURES OF THIOBACILLUS FERROOXIDANS
Keywords: Iron(II) oxidation|Thiobacillus ferrooxidans|redox potential|oxygen|carbon dioxide|off-gas analysis|growth kinetics|
No 3 (2001), p. 249-255
  mag02.pdf (74 kB)
mag02_eng.txt (1 kB)  

Nikulin S.A., Khanzhin V.G., Rojnov A.B.
LABORATORY- AND PRODUCTION-SCALE USE OF A METHOD OF ACOUSTIC EMISSION
Keywords: acoustic emission|material fracture|crack parameters|measurement|
No 3 (2001), p. 256-263
  mag03.pdf (67 kB)
mag03_eng.txt (1 kB)  

BLACHA L., LABAJ J., ZAJACZKOWSKI A.
EINFLUSS DES SAUERSTOFFES IM FLÜSSIGEN KUPFER AUF DIE ANTIMONENTFERNUNG IM VAKUUMRAFFINATIONSPROZESS
Keywords: metallurgy|vacuum metallurgy|metal evaporation|
No 3 (2001), p. 264-275
  mag03.pdf (67 kB)
mag03_eng.txt (1 kB)  

Kizek J., Zsigraiová Z.
BURNING VELOCITIES EXPERIMENTAL DETERMINATION FOR GASEOUS FUELS WITH HIGHER CONTENT OF INERT COMPOUNDS
Keywords: combustion|flame stability|burning velocity|inert|combustion air excess|
No 3 (2001), p. 281-288
  mag03.pdf (67 kB)
mag03_eng.txt (1 kB)  

Pernis R.
INFLUENCE OF UNEQUAL TENSILE STRESS IN ECCENTRIC TUBES ON THE RISE OF LONGITUDINAL CRACKS
Keywords: tube drawing|eccentric tubes|tensile stress|longitudinal cracks|yield planes|
No 3 (2001), p. 299-309
  mag03.pdf (67 kB)
mag03_eng.txt (1 kB)  

Harrer O., Kvačkaj T., Pokorný I.
NUMERICAL SIMULATION OF PLATE ROLLING
Keywords: plate rolling|vibration|rolling force|rolling torque|mathematical simulation|FEM|
No 3 (2001), p. 320-325
  mag03.pdf (67 kB)
mag03_eng.txt (1 kB)  

Harrer O., Kvačkaj T., Pokorný I.
NUMERICAL SIMULATION OF BILLET ROLLING
Keywords: billet rolling|mathematical simulation|tensile stress|FEM|DEFORM 3D|
No 3 (2001), p. 310-319
  mag03.pdf (67 kB)
mag03_eng.txt (1 kB)  

Borkowski S.
THE QUALITY OF METAL PRODUCTS AND THE ENVIRONMENT PROTECTION
Keywords: quality|casting material products|cast-iron|Al-Si alloys|speroidization|metallothermy|environment protection|
No 3 (2001), p. 343-348
  mag03.pdf (67 kB)
mag03_eng.txt (1 kB)