- Layer-Structured Metal Sulfides as Novel Thermoelectric Materials

Author(s):  
V.K. Berry

There are two strains of bacteria viz. Thiobacillus thiooxidansand Thiobacillus ferrooxidanswidely mentioned to play an important role in the leaching process of low-grade ores. Another strain used in this study is a thermophile and is designated Caldariella .These microorganisms are acidophilic chemosynthetic aerobic autotrophs and are capable of oxidizing many metal sulfides and elemental sulfur to sulfates and Fe2+ to Fe3+. The necessity of physical contact or attachment by bacteria to mineral surfaces during oxidation reaction has not been fairly established so far. Temple and Koehler reported that during oxidation of marcasite T. thiooxidanswere found concentrated on mineral surface. Schaeffer, et al. demonstrated that physical contact or attachment is essential for oxidation of sulfur.


TAPPI Journal ◽  
2011 ◽  
Vol 10 (1) ◽  
pp. 17-23
Author(s):  
KEVIN TAYLOR ◽  
RICH ADDERLY ◽  
GAVIN BAXTER

Over time, performance of tubular backpulse pressure filters in kraft mills deteriorates, even with regular acid washing. Unscheduled filter replacement due to filter plugging results in significant costs and may result in mill downtime. We identified acid-insoluble filter-plugging materials by scanning electron microscope/energy-dispersion X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) analysis in both polypropylene and Gore-Tex™ membrane filter socks. The major filter-plugging components were calcium sulfate (gypsum), calcium phosphate (hydroxylapatite), aluminosilicate clays, metal sulfides, and carbon. We carried out detailed sample analysis of both the standard acid-washing procedure and a modified procedure. Filter plugging by gypsum and metal sulfides appeared to occur because of the acid-washing procedure. Gypsum formation on the filter resulted from significant hydrolysis of sulfamic acid solution at temperatures greater than 130°F. Modification of the acid-washing procedure greatly reduced the amount of gypsum and addition of a surfactant to the acid reduced wash time and mobilized some of the carbon from the filter. With surfactant, acid washing was 95% complete after 40 min.


Author(s):  
ASHAQ HUSSAIN SOFI ◽  
BAASIT ABUBAKR ◽  
ANIL MAINI ◽  
MOHAMMAD ASHRAF SHAH

2010 ◽  
Author(s):  
Douglas S. Dudis ◽  
John B. Ferguson ◽  
Michael Check ◽  
Joel E. Schmidt ◽  
Even D. Kemp ◽  
...  

2014 ◽  
Vol 6 (3) ◽  
pp. 152-160 ◽  
Author(s):  
Xiaoshuang Zheng ◽  
Jingdong Liu ◽  
Long Chen ◽  
Jianping Gao ◽  
Yousheng Tao

2020 ◽  
Vol 2020 (10) ◽  
pp. 1102-1115
Author(s):  
M. A. Korzhuev ◽  
I. V. Katin ◽  
M. A. Kretova ◽  
E. S. Avilov

Sign in / Sign up

Export Citation Format

Share Document