Patent
Production of hexavalent chromium for use in chlorate cells
TLDR
By-product hypochlorite from the electrolytic production of chlorates, notably sodium chlorate, is used to form hexavalent chromium for use in the electrolysis process.Abstract:
By-product hypochlorite from the electrolytic production of chlorates, notably sodium chlorate, is used to form hexavalent chromium for use in the electrolysis process by oxidation of trivalent chromium compounds by the hypochlorite. The hypochlorite may be the condensate produced by treatment of the chlorate cell by-product gas stream and/or present in the cell liquor.read more
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Electrochemical removal of chromium from chlorate solutions
TL;DR: In this paper, a trivalent chromium hydroxide is removed from cell liquor or other aqueous media containing the same by cathodically reducing the same, which deposits on the cathode as chromium hyroxide.
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Method for the removal of silicon and heavy metals from aqueous streams
Abstract: A batch or continuous process for the removal by flocculation of silicon and heavy metal contamination from aqueous waste streams by the addition of an aluminum salt, particularly, aqueous streams recycled as electrolyte in the electrolytic production of alkali metal or alkaline earth metal chlorates. The process is particularly suited to the removal of heavy metals and silicon contamination in an electrolyte recycled to an electrolytic cell subsequent to the removal by crystallization of a chlorate salt. An aluminum salt, such as aluminum chloride, aluminum chlorohydrate, and polyaluminum chlorides including polyaluminum chloride sulfates is effective as a flocculating agent.
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Process for making chromium-free orthorhombic sodium sulfate
TL;DR: In this paper, a process for making orthorhombic Na 2 SO 4 containing less than 0.1 ppm chromium from a solution of Na 2SO 4 containing 0. 1 to 100 ppm Cr(III) is described.
References
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Patent
Chromate removal from concentrated chlorate solution by chemical precipitation
TL;DR: In this article, a method for removing hexavalent chromium from concentrated aqueous alkali metal chlorate solution by reacting the solution with an inorganic sulfur containing compound was devised.
Patent
Stripping and recovery of dichromate in electrolytic chlorate systems
TL;DR: In this paper, a process for removing dichromates from chlorate-rich solutions containing the same comprising reducing the hexavalent chromium of the dichromate to trivalent Chromium with a chemical reducing agent and separating the trivalents chromium in the form of chromium hydroxide precipitate is described.
Patent
Process for recovering Cr(VI) ions from a chlorate cell liquor
TL;DR: From a chlorate cell liquor containing an alkali metal chlorate, an alkaline metal chloride and Cr(VI) ions, Cr(vi) ions are recovered by means of a combination of simple chemical procedures and re-used in an electrolysis step.
Patent
Di:chromate removal from chlorate soln. - by redn. with hydroxylamine hydrochloride and pptn. as chromium hydroxide to avoid toxic gas and filtration problems
TL;DR: In this paper, the authors proposed a method to remove dichromate from chlorate solns using hydroxylamine, which avoids the evolution of toxic gases (occurring on redn with Zn(HS)2) and the need for a sepecial filtration stage.