Process for depleting an impurity by electrolysis and recovering electrical energy from its decomposition products

Patent · Tue Mar 30 04:00:00 EST 1982

OSTI ID:5316767

Skala, S F

An electrolyzable impurity, having a lower decomposition voltage than the electrolyte in which it is formed and dissolved, is depleted by operating an electrolysis cell between the decomposition voltages of the impurity and electrolyte. Such electrolytic decomposition of the impurity at a lower voltage does not decompose the electrolyte and enables a high degree of depletion with efficient use of electrical energy. In a preferred system, the impurity is depleted in an electrolysis cell separate from the apparatus in which it is formed and decomposition products of the impurity are recombined in a fuel cell for energy recovery. This process of depleting an impurity is applied to production of sodium metal by electrolysis of molten sodium hydroxide wherein water forms as a decomposition product to function as an impurity which diminishes sodium yield in a secondary reaction. The sodium hydroxide electrolyte with its dissolved water impurity is withdrawn from a first electrolysis cell operating above the decomposition voltage of the sodium hydroxide, flows through a second electrolysis cell operating between the decomposition voltages of the sodium hydroxide and water whereby the water is decomposed into hydrogen and oxygen which are transported to a fuel cell, and is returned as depleted electrolyte to the first electrolysis cell for further electrolysis at an improved current efficiency.

• Assignee: EDB-82-109441
• Patent Number(s): US 4322270
• OSTI ID: 5316767
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
300501* -- Fuel Cells-- Design & Development
300503 -- Fuel Cells-- Materials
Components
& Auxiliaries
ALKALI METAL COMPOUNDS
ALKALI METALS
CHEMICAL REACTIONS
DECOMPOSITION
DESIGN
DIRECT ENERGY CONVERTERS
ELECTRIC POTENTIAL
ELECTRIC POWER
ELECTROCHEMICAL CELLS
ELECTROLYSIS
ELECTROLYTIC CELLS
ELEMENTS
FUEL CELLS
HYDROGEN
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HYDROGEN FUEL CELLS
HYDROXIDES
IMPURITIES
LYSIS
METALS
MOLTEN SALTS
NONMETALS
OXYGEN
OXYGEN COMPOUNDS
POWER
POWER GENERATION
PRODUCTION
REGENERATIVE FUEL CELLS
SALTS
SODIUM
SODIUM COMPOUNDS
SODIUM HYDROXIDES