Patent Publication Number: US-3875039-A

Title: Apparatus for decomposing amalgams

Description:
U United States Patent 11 1 1111 3,875,039  
 Matusek et al. Apr. 1, 1975 [5 APPARATUS FOR DECOMPOSING 2,423,351 7 1947 Taylor 204/219 AMALGAMS 3,464,911 9/1969 Cottam et al. 204/220 [75] inventors: Miroslav Matusek, Pardubice; Milan FOR IGN PATENTS OR APPLICATIONS Franz Laban; 2,036,949 12 1970 France 204/248 Prague of Czechoslovakla 1,229,996 12/1966 Germany 204/248 [73] Assignee: Vyzkumny Ustav Anorganicke Chemle P Laban Primary Examiner.lohn H. Mack Czechoslovak Assistant Examiner-D. R. Valentine {22] Filed: May 29, 1974 [2 1] App]. NO.I 474,454 57 ABSTRACT 52 us. (:1 204/248, 204/249, 204/290 R, l F f z g 204,294 p ura lty vert ca y spacebuars 0 active rrgaterraf as, 51 rm. (:1 BOlk 3/04, BOlk 3/08 g&#39; fi j f f; 52358 2 1 [58] Field of Search 204/248, 249, 99, 150, h l d S h b 204/250 219420 290 R 294 sue as stee are woun uc ars are lspose m vertically disposed vessel, and the amalgam to be de- 56] References Cited composed is flowed thereover.  
  UNITED STATES PATENTS 4 Claims, 2 Drawing Figures 577.134 2/1897 Harrison 204/248 A WIRE GRAPHITE :MEWEU 1 GRAPHITE GPA PHI TE 1 APPARATUS FOR DECOMPOSING AMALGAMS It is well known that with the modern method of electrolysis, various types of apparatus have been proposed for carrying out the reaction between water and an alkalimetal amalgam. Most widely used are vertical apparatus (denuders) packed with pieces of graphite or other active material. The specific capacity of such an apparatus does not usually exceed about 300 kA per m of the decomposing material. Types of vertical apparatus for decomposing amalgam with other than packed material have been already described and patented. They may be filled, for example, with iron wires which have electrical contact with graphite blocks or graphite plates, while metal gauzes or sheets are inserted between each pair of plates.  
  The decomposition rate of the amalgam, in the verti cal denuders filled with graphite plates which are electrically connected with vertical apparatus filled with packed decomposing material is somewhat higher than the denuders described in the preceding paragraph. Owing to the contact between the metal gauzes or sheets and the graphite plates on the surface of such an arranged layer, there are formed amalgam-wettable and electrically conducting regions which reduce the electrical resistance between the amalgam and the active material and avoid the penetration of the electrolyte into the space between the active material and the amalgam. The specific capacity of these apparatus amounts to about 650 kA per m of the packing.  
  According to the present invention, the efficiency of the said denuders can be further improved by a new structure and form of the metal as well as of the graphite constituents of the packing.  
  By use of the present invention the vertical apparatus for decomposing amalgam is provided with a reaction body formed of vertically spaced bars made of active materials, as for example graphite, titanium carbide etc. over which spirals of materials such as steel wettable by amalgam are wound.  
  According to the present invention, up to a threefold increase of the specific output may be reached compared to the output of the denuders comprising graphite plates alternatively spaced with metal gauzes or sheets.  
  The spirals may be of any material which is electrically conductive, is easily amalgam wettable, and is sufficiently resistant to the conditions prevailing in the apparatus. Most suited for this purpose is iron. Satisfactory contact among the bars of active material and the spirals may be achieved by simple taut winding of the wire over smooth bars or into spiral grooves cut or otherwise formed into the said bars. The depth of the grooves should not exceed half the diameter of the wire.  
 In the accompanying drawings:  
  FIG. 1 is a view in side elevation of a single wire wound graphite rod employed in forming the packing of the denuder of the invention, and FIG. 2 is a view in plan of a bundle of rods as shown in FIG. 1 forming the aforesaid packing.  
 EXAMPLE In using a commercial electrolysis cell the current load of kA and the amalgam exit concentration of 0.4% by weight relative to the weight of sodium, a vertical apparatus for decomposing amalgam with the following parameters was employed: the body of the denuder had a regular hexagonal horizontal cross section, with the length of its side of 250 mm. The apparatus was filled with vertically spaced graphite bars of the diameter of 10 mm and the length of 300 mm.  
  The bars were provided with spiral grooves 0.5 mm. deep, into which iron wire having a 1 mm. diameter was tautly wound, the distance between successive turns of the wire axially of the graphite rods being 10 mm. The total number of the bars in the denuder was 1,500. The exit amalgam concentration was about 0.005% of the weight of sodium. The specific capacity of this apparatus amounted to 1,900 kA per m of the packing. The exit concentration of the caustic soda solution was about 50% by weight of NaOI-I with a countercurrent flow of both liquids. A uniform distribution of the am algam flow down the packing was achieved by means of a distributing device of a common type (perforated metal sheet) situated above the layer. The plate supporting the packing was of a strong horizontal steel gauze or grid on which the lower ends of the rods forming the packing rested.  
  Although the invention is illustrated and described with reference to one preferred embodiment thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a preferred embodiment, but is capable of numerous modifications within the scope of the appended claims.  
 What is claimed is:  
  1. In a vertical apparatus for decomposing amalgam having a reaction body composed of a plurality of vertically spaced bars, the improvement wherein the bars are formed of active material non-wettable by amalgam over the surface of which spirals of wire of a material wettable by amalgam are wound.  
  2. Apparatus according to claim 1, wherein the bars are formed of graphite.  
  3. Apparatus according to claim 1, wherein the bars are formed of titanium carbide.  
 4. Apparatus according to claim 1, wherein the wire is made of steel.