Alpersite (Mg,Cu)SO4{middle dot}7H2O, a new mineral of the melanterite group, and cuprian pentahydrite: Their occurrence within mine waste
2006; Mineralogical Society of America; Volume: 91; Issue: 2-3 Linguagem: Inglês
10.2138/am.2006.1911
ISSN1945-3027
AutoresR. C. Peterson, Jane M. Hammarstrom, Robert R. Seal,
Tópico(s)Metal Extraction and Bioleaching
ResumoAlpersite, Mg0.58Cu0.37Zn0.02Mn0.02Fe0.01SO4·7H2O, a new mineral species with direct relevance to reactions in mine waste, occurs in a mineralogically zoned assemblage in sheltered areas at the abandoned Big Mike mine in central Nevada at a relative humidity of 65% and T = 4 °C. Blue alpersite, which is isostructural with melanterite (FeSO4·7H2O), is overlain by a light blue to white layer dominated by pickeringite, alunogen, and epsomite. X-ray diffraction data (MoKα radiation) from a single crystal of alpersite were refined in P21/c, resulting in wR = 0.05 and cell dimensions α = 14.166(4), b = 6.534(2), c = 10.838(3) Å, β = 105.922(6)°, Z = 4. Site-occupancy refinement, constrained to be consistent with the compositional data, showed Mg to occupy the M1 site and Cu the M2 site. The octahedral distortion of M2 is consistent with 72% Cu occupancy when compared with the site-distortion data of substituted melanterite.
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