Effect of relative humidity on oxidation products of arsenopyrite and löllingite

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985831%3A_____%2F22%3A00558660" target="_blank" >RIV/67985831:_____/22:00558660 - isvavai.cz</a>

Alternative codes found

RIV/00216208:11310/22:10448471

Result on the web

<a href="https://www.sciencedirect.com/science/article/pii/S000925412200239X" target="_blank" >https://www.sciencedirect.com/science/article/pii/S000925412200239X</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.chemgeo.2022.120945" target="_blank" >10.1016/j.chemgeo.2022.120945</a>

Result language

angličtina

Original language name

Effect of relative humidity on oxidation products of arsenopyrite and löllingite

Original language description

Arsenopyrite (FeAsS) and löllingite (FeAs2) are among the most common primary As minerals in the wastes produced by mining and associated ore processing activities. This study explores the oxidation of these minerals at high relative humidity that frequently occur in underground mines and unsaturated waste piles and tailings. Our objectives were to examine the effect of relative humidity on the mineralogy of secondary phases that formed after 40 months of exposure of arsenopyrite-rich (Apy) and löllingite-rich (Lö) concentrates to six constant relative humidity (RH) levels between 75% and 100%. X-ray diffraction, electron microprobe, Raman microspectrometry, and sequential extraction results showed that the dominant oxidation product in Apy concentrates at any controlled RH level was poorly crystalline ferric arsenate (PCFA). This phase revealed increasing dehydration, and release of sulfate with increasing RH ≥ 94%, indicating that high humidity accelerates the transformation process of PCFA to scorodite. Newly formed elemental sulfur, parascorodite, hydroniumjarosite, and ferric (hydr)oxides were minor (to trace) phases in Apy concentrates, and the latter two phases only formed on the surface of pyrite as a result of the limited transport of solutes between individual grains of sulfides at RH ≤ 81%. In comparison, well crystallized scorodite and arsenolite were the dominant oxidation products in Lö concentrates at every RH. Increasing RH significantly increased the oxidation rate of sulfide and arsenide minerals in the concentrates. The highest sulfide and arsenide oxidation rates in the Lö concentrate occurred at RH 100%, and was approximately 40 times faster than at RH 81%. In comparison, the highest oxidation rate of sulfides in the Apy concentrate occurred at RH 94%, and was 6 to 7 times faster that than at RH 81%. Differences in the mineralogical compositions of oxidation products in the Apy and Lö concentrate reflect the high levels of sulfate in the Apy concentrate. This triggered formation of PCFA and retarded its transformation to scorodite. The substantial role of sulfate in the oxidation process is reinforced by the finding that stagnation of the sulfide oxidation rate in the Apy concentrate at high RH (> 94%) was probably due to the formation of ferric ion complexes in the presence of high levels of sulfate ions.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10505 - Geology

Project

<a href="/en/project/GA19-18513S" target="_blank" >GA19-18513S: Emerging contaminants and critical metals in smelting wastes: from mineralogy to environmental footprint</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2022

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Chemical Geology

ISSN

0009-2541

e-ISSN

1872-6836

Volume of the periodical

605

Issue of the periodical within the volume

September

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

12

Pages from-to

120945

UT code for WoS article

000810956500004

EID of the result in the Scopus database

2-s2.0-85131442481