Formation of Massive Gunningite-Jarosite Scale in an Industrial Zinc Pressure Leach Autoclave: A Characterization Study

In this study, the rapid reduction of selenious ions using sulfite species at negative pH is described and its use as analytical technique in combination with turbidimetry is proposed. It was found that Se(IV) can be reduced quantitatively at ambient temperature via a combination of sulfite reduction and ultra-acidification with sulfuric acid to a colloidal form that can be determined using turbidimetry. The developed analytical procedure can accurately and reproducibly measure Se(IV) concentrations down to 1 mg/L. For concentrations above 20 mg/L dilution is necessary. Common transition metal ions such as iron(II), copper(II), or zinc(II) up to 10 g/L concentration were found not to have noticeable influence on the precision of the method. Finally the developed technique was shown to be equally effective with real Se(IV)-bearing industrial solutions generated in a zinc concentrate roasting operation, hence making the method particularly useful as a fast and simple process monitoring and control tool.

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“…This was confirmed (see XRD pattern in Fig. 2) via its recrystallization in boiling toluene solution (5,26).…”

Section: Colloidal Selenium Precipitatesupporting

confidence: 61%

The Rapid Measurement and Monitoring of Selenite Concentration by Turbidimetry Following its Conversion to Colloidal State by Sulfite Reduction and Acidification

Geoffroy¹,

Demopoulos²

2012

Separation Science and Technology

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“…For example, it is expected to have both hematite and elemental sulfur as the major constituent of this produced residue; however, upon the analysis of this product with Raman spectroscopy, only hematite could be observed and not in any way elemental sulfur nor any arsenate type of phase. It was only after the elemental sulfur was removed via the chemical method describe in some of our earlier work on other industrial samples (Becze et al, 2009) that the elemental sulfur was extracted and re-crystallized, then Raman spectra was collected to ensure that indeed it was elemental sulfur. Before or after extraction of the elemental sulfur no Raman active arsenate phases were detected.…”

Section: Discussion and Resultsmentioning

confidence: 99%