{HEAD ~ The sulfur contents} reach up to 15,000 ppm, {TAIL ~ preferably between 4,000 and 9,000 ppm} 
{ HEAD ~ The sulfur contents } reach up to 15,000 ppm , { TAIL ~ preferably between 4,000 and 9,000 ppm }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL