Sulfex process

The Permutit Company, Proceedings of Seminar on Metal Wastes Treatment Featuring the Sulfex Process, The Permutit Co., Paramus, N.J., 1978. 

F2. Fisher, F. D. The Sulfex Process Terminal Development Report, USAEC Report HW-66439, Aug. 22, 1960. 

The layout of a Sulfex plant is shown in Fig. 6.6. A preliminary hydroxide precipitation reduces the amount of solids produced by the Sulfex process, as well as the amount of more expensive iron sulphide required, thus keeping down costs. Table 6.4 sets out comparative costs of treatment by hydroxide precipitation and the Sulfex process. A direct comparison is nevertheless complicated by the greater efficiency of the Sulfex process. 

Table 6.4 Comparative cost of heavy metal removal by hydroxide precipitation and the Sulfex Process (based on [25].

Sulfex [Sulfide extraction] A process for removing heavy metals from waste streams by adding ferrous sulfide to precipitate them as their sulfides. Developed by the Permutit Company and now owned by U.S. Filter/Warrendale. Not to be confused with SULF-X or Sulph-X. 

SULF-X [Sulfur extraction] A regenerable flue-gas desulfurization process in which the sulfur dioxide is absorbed by aqueous sodium sulfide in a bed packed with pyrite. Ferrous sulfate is produced this is removed by centrifugation and calcined with coke and fresh pyrite. Sulfur vapor is evolved and condensed, and the residue is re-used in the scrubber. Piloted in the mid-1980s. Not to be confused with Sulfex or Sulph-X. 

Sulph-X A process for trapping sulfur in coal combustion. A proprietary mixture of inorganic salts, including sodium chloride, is mixed with the coal and combines with the sulfur dioxide so that it remains fixed in the ash instead of evolving with the combustion gases. Invented in China and developed in Australia in the 1990s by Coal Corporation Pty. Not to be confused with Sulfex or SULF-X. 

Sulfur and several sulfides, highly insoluble precipitates with solubility products as low as 1.6 X 10 for mercuric sulfide, have been used to concentrate trace metals from water. Sulfur, produced from (NH4)aS and HNO3 ( 0), coprecipitated several metals including mercury. Iron(III) sulfide (also used in a commercial process SULFEX) removes several metals (61) and is better than hydroxide in the presence of EDTA and other chelating agents (62). Lead sulfide has been used to collect silver for aqueous solution (63), molybdenum sulfide to collect arsenic from 2 M hydrochloric acid solution (64), and copper sulfide to concentrate cobalt and zinc from seawater (65). 

Scott, M. C. (1978), Sulfex - A new Process Technology for Removal of Heavy Metals from Waste Streams, Proceedings of the 32nd Industrial Waste Conference, May, 1977, Purdue University, Ann Arbor Science, Ann Arbor, Michigan, pp. 622-29. 

Sulfuric Acid 6.0M Boiling Boiling — U — — 24 hrs.. processes for the aqeuous reprocessing of spent fuel elements Sulfex and Thorex processes... 

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