US2321523A - Method of reclaiming selenium elements - Google Patents

Method of reclaiming selenium elements Download PDF

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Publication number
US2321523A
US2321523A US448863A US44886342A US2321523A US 2321523 A US2321523 A US 2321523A US 448863 A US448863 A US 448863A US 44886342 A US44886342 A US 44886342A US 2321523 A US2321523 A US 2321523A
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United States
Prior art keywords
selenium
reclaiming
counter
electrode
selenium elements
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Expired - Lifetime
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US448863A
Inventor
Saslaw Otto
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STC PLC
Federal Telephone and Radio Corp
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Standard Telephone and Cables PLC
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Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to US448863A priority Critical patent/US2321523A/en
Application granted granted Critical
Publication of US2321523A publication Critical patent/US2321523A/en
Priority to GB10277/43A priority patent/GB564464A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/06—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials
    • H01L21/10—Preliminary treatment of the selenium or tellurium, its application to the foundation plate, or the subsequent treatment of the combination
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/06—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials
    • H01L21/10—Preliminary treatment of the selenium or tellurium, its application to the foundation plate, or the subsequent treatment of the combination
    • H01L21/101—Application of the selenium or tellurium to the foundation plate

Definitions

  • Fig. 2 is a side view in cross section.
  • the selenium element comprises a base plate I ordinarily of steel which is preferably nickel plated on its top surface, and a coating 2 of selenium which has been annealed by heat treating in a well-known manner to crystallize the selenium.
  • the annealing is ordinarily done in two heat treatment steps: The first step involves heating to around 120 C. under pressure in some sort of a jig for about a half hour; .and the second step involves heating without pressure for some hours at a higher temperature just under the meltingpoint of selenium for example, about 214 C.
  • a treatment is then usually given the selenium with selenium dioxide vapor, after which a conducting counter-electrode 3, ordinarily an alloy of tin, bismuth and cadmium, is sprayed over the selenium surface.
  • the breakdown is in the form of an arc which burns through the selenium from the counter-electrode to the base plate, thereby destroying the element.
  • I treat a destroyed or rejected selenium element with hydrochloric acid, which may be of practically any concentration for this purpose. Both concentrated HCl and a 50% concentration HCl have been found satisfactory, for example. This acid it to become separated from the selenium. The surface layer on the selenium just beneath the counter-electrode should then preferably be scraped as by sandpaper. Thereafter, I heat the plate containing the remaining selenium coating 2 sufiiciently to fuse the selenium just enough to cause it to ilow together somewhat to eliminate any effect of a breakdown.
  • the pressure is not critical as a high pressure of 1,000 lbs. per square inch or more, but preferably in the order of about 8,000
  • the selenium layer is in the condition it was at the end of the first heat treatment step in its initial annealing.
  • the disc is then subjected to the second heat treatment step by placing in an oven at about 214 centigrade for about one-half hour.
  • the method of reclaiming a selenium ele ment which comprises applying hydrochloric acid, then fusing the remaining selenium and allowing it subsequently to harden, then pressing selenium powder in the uneven portions of the selenium surface at a high pressure and an elevated temperature.
  • a method of reclaiming a plate coated with selenium and with a counter-electrode over the selenium which comprises dissolving oil the counter-electrode in hydrochloric acid, then fusing the selenium remaining on the plate and allowing it subsequently to harden, then pressing selenium powder into the hardened selenium surface at a high pressure of around a thousand pounds per square-inch temperature.
  • the method of reclaiming d selenium coated I element having a counter-electrode coating over the selenium which comprises removing the coun- 4.
  • the method according to claim 3 which assume or more and an elevated comprises the additional step or a second heat treatment without pressure and at a higher temperature below the melting; point of selenium.

Description

June 8, 1943. o, SASLAW 2,321,523
METHOD OF RECLAIMING SELENIUM ELJEWIEII'IS Filed June 2'7, 1942 INVENTOR. OTTO SASLAW A ORNEY.
Patented June 8, 1943 UNITED QSTATE PATENT, OFFICE METHOD OF RECLAIMING SELENIUM ELEItIENTS Otto ,iSaslaw, Kearny, N. J., assignor to Federal Telephone and Radio Corporation, a corporation of Delaware Application June 27, 1942, Serial No. 448,863
s Claims.
treatment removes the counter-electrode layer apparently by dissolving the tin in the alloy which thereby undermines the layer 3 causing broken-down and rejected selenium elements,
-there has resulted great waste of the selenium and base plate and also of the work and processing performed on the element in making it.
In accordance with my invention this waste is largely eliminated by reclaiming the base plate together with most of the selenium and saving at least some of the processing steps. The invention will be better understood from the following detailed description and the accompanying drawing of which Fig. 1 illustrates a face view of a selenium rectifier element; and
Fig. 2 is a side view in cross section.
In the drawing the selenium element comprises a base plate I ordinarily of steel which is preferably nickel plated on its top surface, and a coating 2 of selenium which has been annealed by heat treating in a well-known manner to crystallize the selenium. The annealing is ordinarily done in two heat treatment steps: The first step involves heating to around 120 C. under pressure in some sort of a jig for about a half hour; .and the second step involves heating without pressure for some hours at a higher temperature just under the meltingpoint of selenium for example, about 214 C. A treatment is then usually given the selenium with selenium dioxide vapor, after which a conducting counter-electrode 3, ordinarily an alloy of tin, bismuth and cadmium, is sprayed over the selenium surface.
When such a rectifying element breaks down under voltage, the breakdown is in the form of an arc which burns through the selenium from the counter-electrode to the base plate, thereby destroying the element.
In accordance with my invention I treat a destroyed or rejected selenium element with hydrochloric acid, which may be of practically any concentration for this purpose. Both concentrated HCl and a 50% concentration HCl have been found satisfactory, for example. This acid it to become separated from the selenium. The surface layer on the selenium just beneath the counter-electrode should then preferably be scraped as by sandpaper. Thereafter, I heat the plate containing the remaining selenium coating 2 sufiiciently to fuse the selenium just enough to cause it to ilow together somewhat to eliminate any effect of a breakdown. I then allow the disc to cool and then press a relatively small amount of vitreous selenium powder within the uneven portions left on the surface of the cooled selenium, using a high pressure and an elevated temperature. The pressure is not critical as a high pressure of 1,000 lbs. per square inch or more, but preferably in the order of about 8,000
pounds per square inch will do. The temperature at this pressure may satisfactorily be around 0., although it may be varied considerably from this. It should not be hot enough to melt the selenium, of course.
At this stage, the selenium layer is in the condition it was at the end of the first heat treatment step in its initial annealing. The disc is then subjected to the second heat treatment step by placing in an oven at about 214 centigrade for about one-half hour.
By the use of this reclaiming process I have succeeded in saving the work and hours of time ordinarily used in coating the selenium on the base plate and heat treating it in the initial heat treatment steps under pressure. In addition to this saving of time and work there is the additional saving of the base plate and the selenium layer which would be lost if the element were thrown away.
I claim:
1. The method of reclaiming a selenium ele ment which comprises applying hydrochloric acid, then fusing the remaining selenium and allowing it subsequently to harden, then pressing selenium powder in the uneven portions of the selenium surface at a high pressure and an elevated temperature.
2. A method of reclaiming a plate coated with selenium and with a counter-electrode over the selenium which comprises dissolving oil the counter-electrode in hydrochloric acid, then fusing the selenium remaining on the plate and allowing it subsequently to harden, then pressing selenium powder into the hardened selenium surface at a high pressure of around a thousand pounds per square-inch temperature.
a. The method of reclaiming d selenium coated I element having a counter-electrode coating over the selenium which comprises removing the coun- 4. The method according to claim 3 which assume or more and an elevated comprises the additional step or a second heat treatment without pressure and at a higher temperature below the melting; point of selenium.
5. The method of reclaiming a selenium coated element having a counter-electrode coating over the selenium which comprises? removing the.
counter-electrode by application or hydrochloric acid, then scraping the selenium. surface, then fusing the remaining selenium somewhat and allowing it subsequently to harden, then pressing selenium powder into the selenium surface at a high pressure and an elevated temperature.
o'rrd SASLAW.
US448863A 1942-06-27 1942-06-27 Method of reclaiming selenium elements Expired - Lifetime US2321523A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US448863A US2321523A (en) 1942-06-27 1942-06-27 Method of reclaiming selenium elements
GB10277/43A GB564464A (en) 1942-06-27 1943-06-25 Method of reclaiming selenium elements of the electric current rectifier type

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2459886A (en) * 1945-11-02 1949-01-25 Lorain Prod Corp Selenium rectifier
US2842830A (en) * 1953-10-02 1958-07-15 Int Standard Electric Corp Process for the manufacture of selenium rectifier
US3046176A (en) * 1958-07-25 1962-07-24 Rca Corp Fabricating semiconductor devices
US3955168A (en) * 1974-09-03 1976-05-04 General Electric Company Rejuvenation method for varistors

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2459886A (en) * 1945-11-02 1949-01-25 Lorain Prod Corp Selenium rectifier
US2842830A (en) * 1953-10-02 1958-07-15 Int Standard Electric Corp Process for the manufacture of selenium rectifier
US3046176A (en) * 1958-07-25 1962-07-24 Rca Corp Fabricating semiconductor devices
US3955168A (en) * 1974-09-03 1976-05-04 General Electric Company Rejuvenation method for varistors

Also Published As

Publication number Publication date
GB564464A (en) 1944-09-28

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