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# FeOtot recalculation to FeO and Fe2O3 by stoichiometry

Posted by Łukasz Kruszewski

FeOtot recalculation to FeO and Fe2O3 by stoichiometry March 16, 2011 08:38AM |
Registered: 8 years ago Posts: 767 |

Hello everyone!

Would like to ask if you know about a "universal" method to recalculate FeOtot to FeO and Fe2O3 by stoichiometry? I know about a method of Carmichael, i.e. recalculation on ulvospinel and ilmenite basis, but it seems to be only for spinels (please correct me if I'm wrong).

Is there a formula for such recalculation for any mineral?

Best regards,

Luke

Would like to ask if you know about a "universal" method to recalculate FeOtot to FeO and Fe2O3 by stoichiometry? I know about a method of Carmichael, i.e. recalculation on ulvospinel and ilmenite basis, but it seems to be only for spinels (please correct me if I'm wrong).

Is there a formula for such recalculation for any mineral?

Best regards,

Luke

Re: FeOtot recalculation to FeO and Fe2O3 by stoichiometry March 16, 2011 01:24PM |
Registered: 9 years ago Posts: 708 |

I calculate formulas in xcel-spreadsheats. I then put analysed Fe expressed as FeO* in one column. Then I have one cell for FeO (which is the value I play with) and one for Fe2O3.

Then "calculating" FeO and Fe2O3 is done the following way:

First your mineral must have some constraining conditions, i.e. total number of oxygens or cations, etc. which you have as a formula in one of the cells.

Then in the Fe2o3 cell you put the formula

(FeO*-FeO) x 1,11138

In the FeO-cell you now assign a value and check your "constraining condition cell" and adjust until it has the right value.

cheers

Then "calculating" FeO and Fe2O3 is done the following way:

First your mineral must have some constraining conditions, i.e. total number of oxygens or cations, etc. which you have as a formula in one of the cells.

Then in the Fe2o3 cell you put the formula

(FeO*-FeO) x 1,11138

In the FeO-cell you now assign a value and check your "constraining condition cell" and adjust until it has the right value.

cheers

Re: FeOtot recalculation to FeO and Fe2O3 by stoichiometry March 16, 2011 02:26PM |
Registered: 9 years ago Posts: 7,149 |

Re: FeOtot recalculation to FeO and Fe2O3 by stoichiometry March 16, 2011 07:18PM |
Registered: 8 years ago Posts: 767 |

Re: FeOtot recalculation to FeO and Fe2O3 by stoichiometry March 16, 2011 11:44PM |
Registered: 9 years ago Posts: 2,930 |

Re: FeOtot recalculation to FeO and Fe2O3 by stoichiometry March 17, 2011 08:21AM |
Registered: 8 years ago Posts: 767 |

Egbo Akpesiri
FeO and Fe2O3 June 21, 2012 03:44PM |

Re: FeO and Fe2O3 June 21, 2012 04:16PM |
Registered: 9 years ago Posts: 7,149 |

Shah Alam
Calculation of FeO from Fe2O3 wt% July 26, 2012 06:01PM |

Re: FeOtot recalculation to FeO and Fe2O3 by stoichiometry August 31, 2012 10:52PM |
Registered: 9 years ago Posts: 2,930 |

BISHADY
how to calculate FeO/Fe2O3 FROM THE MICROBROBE Fe2O3 ANALYSIS January 11, 2014 02:25PM |

Re: FeOtot recalculation to FeO and Fe2O3 by stoichiometry January 12, 2014 03:54AM |
Registered: 9 years ago Posts: 111 |

A wet chemical analysis I know involves dissolving a known weight of the dry mineral powder in suitable acids under conditions that exclude oxygen, dilute suitably and titrate with standard permanganate to get the Iron2. If you then pass the resulting solution or an aliquot of the stock solution, through a Jones Reductor (amalgamated zinc in a burette-like tube) the Iron will end up being reduced to Iron2.

One then titrates with permanganate again to get the total iron.

Is that what you were looking for?

John Attard, San Diego, California.

One then titrates with permanganate again to get the total iron.

Is that what you were looking for?

John Attard, San Diego, California.

Hassan tharwat
calculation FeOtot from Fe2O3 January 12, 2014 05:12PM |

Re: calculation FeOtot from Fe2O3 January 12, 2014 11:32PM |
Registered: 6 years ago Posts: 190 |

Re: FeOtot recalculation to FeO and Fe2O3 by stoichiometry January 13, 2014 11:25AM |
Registered: 9 years ago Posts: 146 |

There is no general way to recalculate Fe2+ and Fe3+. It is too difficult in many silicates. There are undetermined other elements, vacancies, uncertain water/OH content, more elements with different oxidation state etc. Sometimes you can use "brute force" - like calculating garnet on 12 anions and 8 cations with valence calculation - but of course results of this may be quite far from reality.

The wet analysis is impossible for mixed, altered or too small minerals. You may avoid undetermined elements by using LA-ICP-MS, sometimes just this helps to get the formula. Sometimes the structure can help, eg. if you can say there is no Fe in position typical for Fe3+ - Raman and IR spectroscopy or xray diffraction help with this. The most efficient method is to use Mossbauer spectroscopy which can directly analyse and distinguish Fe2+ and Fe3+.

To get FeO to Fe2O3 just multiply FeO by 1,11111... Fe2O3 to FeO is just reverse, divide Fe2O3 by 1,11111 (or multiply by 0,899999 as said above).

The wet analysis is impossible for mixed, altered or too small minerals. You may avoid undetermined elements by using LA-ICP-MS, sometimes just this helps to get the formula. Sometimes the structure can help, eg. if you can say there is no Fe in position typical for Fe3+ - Raman and IR spectroscopy or xray diffraction help with this. The most efficient method is to use Mossbauer spectroscopy which can directly analyse and distinguish Fe2+ and Fe3+.

To get FeO to Fe2O3 just multiply FeO by 1,11111... Fe2O3 to FeO is just reverse, divide Fe2O3 by 1,11111 (or multiply by 0,899999 as said above).

Maarten VU
Re: FeOtot recalculation to FeO and Fe2O3 by stoichiometry January 21, 2014 09:31AM |

Zbynek Burival Wrote:

-------------------------------------------------------

>

> To get FeO to Fe2O3 just multiply FeO by

> 1,11111... Fe2O3 to FeO is just reverse, divide

> Fe2O3 by 1,11111 (or multiply by 0,899999 as said

> above).

What is the calculation behind this? Where does the number 1,1111 come from?

I have my XRF analysis in Fe2O3, but my modelling program only accepts FeO. So I would like to know how the 1,1111 is calculated.

-------------------------------------------------------

>

> To get FeO to Fe2O3 just multiply FeO by

> 1,11111... Fe2O3 to FeO is just reverse, divide

> Fe2O3 by 1,11111 (or multiply by 0,899999 as said

> above).

What is the calculation behind this? Where does the number 1,1111 come from?

I have my XRF analysis in Fe2O3, but my modelling program only accepts FeO. So I would like to know how the 1,1111 is calculated.

Re: FeOtot recalculation to FeO and Fe2O3 by stoichiometry January 21, 2014 12:33PM |
Registered: 9 years ago Posts: 708 |

Deva Ram
Re FeO and Fe2O3 availabe and Feo (t)from fe2o3 Total September 14, 2014 09:10AM |