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Recovery of sulfur from phosphogypsum: conversion of calcium sulfide to sulfur.

Authors
Rice-DA; Carter-OC Jr.; May-A; Ragin-MM; Swanton-RG
Source
Tuscaloosa, AL: U.S. Department of the Interior, Bureau of Mines, RI 9297, 1990 Jan; :1-15
Link
NIOSHTIC No.
10007493
Abstract
As part of a cooperative effort between the Bureau of Mines and the Florida Institute of Phosphate Research (FIPR), with input from the phosphate industry, the conversion of phosphogypsum to sulfur is being investigated. The proposed process incorporates the thermal reduction of phosphogypsum to calcium sulfide (CaS) and a hydrometallurgical treatment to convert calcium sulfide to sulfur. The research described herein is focused on the latter half of the process. It was demonstrated that calcium sulfide could be converted to ammonium bisulfide (NH4SH), and that ammonium bisulfide could be oxidized by air in the presence of a catalyst to elemental sulfur, which was adsorbed on the catalyst. Two methods for recovering sulfur from the catalyst were developed: (1) thermal treatment to volatilize sulfur, and (2) leaching the sulfur from the catalyst with liquid anhydrous ammonia. Over 90 pct of the sulfur adsorbed on activated carbon (the catalyst) was recovered by both methods. Based upon the encouraging laboratory investigations, a hydrometallurgical scheme was proposed for the overall conversion of calcium sulfide to elemental sulfur.
Keywords
Carbon; Tables-Data; Graphs-Charts; Temperature; Chemical-reactions; Sulfur; Mining; Materials-recovery
Publication Date
19900101
Document Type
IH; Report of Investigations
Fiscal Year
1990
NTIS Accession No.
PB90-225897
NTIS Price
A03
Identifying No.
RI-9297
NIOSH Division
TURC
Source Name
Recovery of sulfur from phosphogypsum: conversion of calcium sulfide to sulfur
State
AL; FL
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