Coking coal commodity Critical Material

Culture-associated sulfur-content reduction in Tabas coking-coal feed

Experimental Context & Analytical Limits:
Section 2.2 describes cultures obtained from the Sarcheshme Copper Complex R&D Center, reported to contain Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans. Section 2.4 specifies a 1:1:1 mixture without strain accessions or member-specific controls. Eastern Parvadeh PE primary feed was crushed to a reported +180/-350 micrometre fraction. The B4C1 and B4B2 preparations include flotation and heavy-liquid concentrates; their protocol is not silently equated to raw PE. The culture was grown for 14 days before exposure, without coal adaptation, using iron- and sulfur-supplemented medium. Sections 2.2 and 2.4 call the medium 9K and K9 and describe the iron amendment differently, so no unique iron concentration is inferred. Coal incubations used 100 mL liquid in 250 mL flasks at 34 degrees C, 150 rpm, initial pH 1.7, 5-10% w/v coal and 10-20% v/v inoculum for 10-20 days. Uninoculated comparisons contained medium, coal and 3% w/w thymol. Evaporation was compensated with water acidified to pH 1.7. Residues were filtered, washed with 10% v/v HCl and dried at 60-70 degrees C for 5-6 hours before analysis. The authors report ASTM-D3177 sulfur and ASTM-D3174 ash analyses; exact sulfur-speciation implementation is not documented. Replicate numbers and the meaning of figure error bars were not specified in the inspected full text.

Curated Evidence Points: