US3497432A - Process for reducing the hydrogen content in chlorine gas produced by alkali-metal chloride electrolysis - Google Patents

Process for reducing the hydrogen content in chlorine gas produced by alkali-metal chloride electrolysis Download PDF

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Publication number
US3497432A
US3497432A US673987A US3497432DA US3497432A US 3497432 A US3497432 A US 3497432A US 673987 A US673987 A US 673987A US 3497432D A US3497432D A US 3497432DA US 3497432 A US3497432 A US 3497432A
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United States
Prior art keywords
alkali
mercury
metal
hydrogen
metal chloride
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Expired - Lifetime
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US673987A
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English (en)
Inventor
Gerhard Hauck
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Dynamit Nobel AG
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Dynamit Nobel AG
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    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25BELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00Electrolytic production of inorganic compounds or non-metals
    • C25B1/01Products
    • C25B1/34Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis
    • C25B1/36Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis in mercury cathode cells

Definitions

  • the invention lies in the finding that copper, zinc, tin, lead or indium are capable of forming an intermetallic compound with the so-called troublesome metals, i.e., chromium, germanium, tungsten, nickel, cobalt, etc., the intermetallic compound being soluble in mercury, unlike the troublesome metal, thereby preventing their concentration at the mercury cathode surface and thus reducing or eliminating the evolution of hydrogen.
  • troublesome metals i.e., chromium, germanium, tungsten, nickel, cobalt, etc.
  • This invention relates to a process for reducing the hydrogen content in chlorine gas produced by alkali metal chloride electrolysis.
  • this invention relates to a process for reducing or eliminating evolution of hydrogen at the mercury cathode in the amalgam process of alkali metal chloride electrolysis.
  • the salt brines that are used in the electrolysis procedure are first subjected to a preliminary purification, which consists of a precipitation treatment with alkali carbonate and barium carbonate.
  • a preliminary purification which consists of a precipitation treatment with alkali carbonate and barium carbonate.
  • the precipitation of the calcium ions is necessary because in their presence iron exhibits a troublesome effect.
  • the fine barium sulfate that precipitates not only removes the sulfate ions which are generally considered responsible for the oxidative ablation of the anodes, but also most of the above-mentioned troublesome metals. However, small amounts of troublesome metals still remain in the brine and are the cause of the evolution of hydrogen at the mercury cathode.
  • the metals which are suitable for use in accordance with the invention for forming the intermetallic compounds can also be added in the form of their soluble salts, e.g., as chlorides, to the alkali brine.
  • the metals which can be used for formation of mercury-soluble intermetallic compounds include copper, zinc, tin, lead and indium.
  • Me represents a troublesome metal that is reduced to the metal at the mercury cathode.
  • Me represents a metal that is easily soluble in mercury. It is apparent that the speed of reactions 2 and 2a determines the amount of hydrogen evolution. That is to say, if the speed of the reactions 2 and 2a are greater than that of reaction 1, the troublesome metal is immediately dissolved in the mercury as a binary compound and exerts no effect on the evolution of hydrogen. If the speed of the reactions 2 and 2a is less than that of reaction 1, the troublesome metal, depending on how much of it is in the brine, can concentrate at the mercury surface and thus give rise to the formation of hydrogen.
  • Example 1 was modified to the extent that copper amalgam was used instead of zinc amalgam. In this case, also, no hydrogen gas was developed when chromium salts were added to the brine in excess of the concentration mentioned in Example 1.
  • EXAMPLE 3 No hydrogen gas was developed when chromium salts were added to the brine as set out in Examples 1 and 2 when an indium amalgam (indium content 0.01 molepercent) was used instead of zinc or copper amalgam.
  • Process for the reduction or elimination of hydrogen development at the mercury cathode in the amalgam process of alkali-metal chloride electrolysis which takes place due to the presence in the alkali brine of at least one metal impurity which comprises incorporating at least one metal selected from the group consisting of copper, zinc, tin, lead and indium capable of forming an intermetallic mercury-soluble compound with said metal impurity into the mercury in an amount of 0.001 to 0.5 mole-percent.
  • the step for reducing or eliminating hydrogen development at the mercury cathode due to the presence of at least one metal impurity in the alkali rbrine which comprises incorporating into the mercury at least one metal selected from the group consisting of copper, zinc, tin, lead and indium capable of forming an intermetallic mercury-soluble compound with the metal impurity in an amount of 0.001 to 0.5 mole-percent.
  • a mercury cathode for use in the amalgam process of alkali metal chloride electrolysis having incorporated therein 0.001 to 0.5 mole-percent of a metal selected from the group consisting of copper, Zinc, tin, lead and indium capable of forming an intermetallic mercury-soluble compound with a metal selected from the group consisting of tungsten, nickel, cobalt, molybdenum, vanadium, arsenic, antimony, beryllium, magnesium, titanium, Zirconium, calcium, barium, aluminum, iron, chromium, and germanium.

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Press-Shaping Or Shaping Using Conveyers (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)
US673987A 1966-10-10 1967-10-09 Process for reducing the hydrogen content in chlorine gas produced by alkali-metal chloride electrolysis Expired - Lifetime US3497432A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DED0051266 1966-10-10

Publications (1)

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US3497432A true US3497432A (en) 1970-02-24

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US673987A Expired - Lifetime US3497432A (en) 1966-10-10 1967-10-09 Process for reducing the hydrogen content in chlorine gas produced by alkali-metal chloride electrolysis

Country Status (8)

Country Link
US (1) US3497432A (de)
AT (1) AT274857B (de)
BE (1) BE704860A (de)
CH (1) CH492640A (de)
DE (1) DE1567931B2 (de)
GB (1) GB1146805A (de)
NL (1) NL6713704A (de)
NO (1) NO117917B (de)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3091579A (en) * 1960-03-02 1963-05-28 Electrochemical Processes Inc Electrochemical process and apparatus with purification of mercury
US3114686A (en) * 1959-06-19 1963-12-17 Ici Ltd Process for the production of electrolytic products by the electrolysis of brine andapparatus therefor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3114686A (en) * 1959-06-19 1963-12-17 Ici Ltd Process for the production of electrolytic products by the electrolysis of brine andapparatus therefor
US3091579A (en) * 1960-03-02 1963-05-28 Electrochemical Processes Inc Electrochemical process and apparatus with purification of mercury

Also Published As

Publication number Publication date
AT274857B (de) 1969-10-10
BE704860A (de) 1968-02-15
NO117917B (de) 1969-10-13
GB1146805A (en) 1969-03-26
CH492640A (de) 1970-06-30
DE1567931B2 (de) 1974-06-12
NL6713704A (de) 1968-04-11
DE1567931A1 (de) 1970-10-01

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