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Studies on iron pyrite

University of British Columbia

The amount of reaction between pyrite and vapor state nitric acid-has been analytically determined at 130°, 145°, 160° and 175° C. for one hour reaction time, and for one-half, one and two hour reaction times at 160°C. The variation of pressure with time for constant-boiling (68.2 per cent) nitric acid was studied at 130° and 160°C The reaction observed between pyrite and vapor state nitric acid followed the possible chain of reactions given below: (formula omitted) with the possible reaction: Fe₂(S0₄)₃ + H₂S0₄⇄Fe₂(S0₄)₃ . H₂SO₄. At 160°C the overall reaction was found to be of an apparent zero-order as was also that for the formation of ferric sulfate and ferric oxide, over the range of almost 100 per cent decomposition of the nitric acid. The maximum amount of pyrite used was about 11 per cent. Experimental results show that reactions (3), (4),(5) and (6) must all be surface reactions. A decrease in the rates of the reactions was noted between 145° and 160°C. This was most probably caused by the change in the physical and chemical properties of sulfur in this range, and indicates that elemental sulfur has a significant retarding effect on the rate of the overall reaction

Text

2012-02-02

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http://hdl.handle.net/2429/40433

Chemical and Biological Engineering

University of British Columbia

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