More Questions: 2. In what form do the Chemical species reside in the Chromite? Why does the nominal composition of Chromite differ from its Chemical analysis? 3. Chemical species that do not occur in Chromite will occur in other valuable minerals or in gangue. Which Chemical species might these be? 4. What valuable minerals might these be? 5. What is gangue? 6. Is Chromite a mineral or a phase in this instance? If it is a mineral, what is its stoichiometry? If it is a phase, what is its stoichiometry? 7. At what temperature would you need to run the furnace so that the Chromite concentrate (the "charge ") drops into a liquid bath? 8. Is this the temperature at which Chromite furnaces typically run?
Question Guidance:
You are an engineer assigned to a ferrochrome smelter. The principal feed to the furnace is a concentrate of Chromite (nominally FeCr2O4). Once a week the concentrator sends through a chemical analysis of the Chromite concentrate. The following summaries that analysis (in mass %) for one week in the year. Cr2O3 46.3, FeO 20.2, Fe2O3 4.0, SiO2 1.1, CaO 0.2, MgO 11.5, Al2O3 14.5.
You will find answers to these questions in academic textbooks on crystallochemistry, mineralogy, geochemistry, and metallurgy.
ZJ
Which of the textbooks please? Can you please check and refer me to the particular textbook that has answers to the questions. Thanks
It depends on whether you only need urgent answers to these specific questions or if you would like to know more about these topics at all. Half a century ago I graduated in geology in the field of mineralogy and geochemistry, so I do not know what to recommend to you from modern professional literature.
Only indicative data can be derived from the data given in the last paragraph.
The chromium content in the concentrate is approx. 31.7% (103.99 / 151.99 x 46.3%). We do not know whether the other minerals (phase) present in the concentrate contain significant admixtures of chromium. If all the chromium is concentrated in the chromite and it has a composition exactly as in the formula FeCr2O4, then the chromite is about 68.2% (223.83 / 151.99 x 46.3%). But we know that chromites contain, apart from Fe (II) and Cr, also significant amounts of Mg (in place of Fe (II) and Al (in place of Cr), and other elements may also be admixed. Therefore, the calculation, based on the results of the analysis, of the actual content of this mineral in the concentrate requires the knowledge of the chemical composition of this particular chromite, which is behind the general formula (Fe, Mg) (Cr, Al) 2O4.
The answers to your other questions require knowledge of the results of analyzes of the mineral (phase) composition of the concentrate and the chemical composition of the individual non-chromite minerals.
The last questions concern the metallurgical technology for the processing of chromium ore concentrate into ferrochrome and the answers are to be found in the metallurgy handbook.
ZJ
@ZJ,
Thanks alot for your useful contribution. I will go through it and revert as time as possible.
Your contribution to the second question on weight of flue dust in relation to the concentration of Zinc sulfide will be more appreciated. Warm regards
Hi Chinedu, I found these articles helpful and the link on Science direct
https://www.sciencedirect.com/topics/earth-and-planetary-sciences/chromite
https://www.sciencedirect.com/topics/chemistry/chromium-ore
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