US2356329A - Method for thfe separation and rec - Google Patents

Description

Aug. 22, 1944. 2,356,329

METHOD FOR THE SEPARATIONAND REGLAMATION oF COPPER FROM PRINTNG PLATES AND THE LIKE vFiled May 23, 1 942 Jr-el Zand) Patented Aug. 1944 LAMATION F METHOD Fon 'ma PLATES Nnfrn Axel E. Lundbye, Springileld, Ohio, assignorto The Crowell-Collier Publishing Company,

SEPARATION AND REC- OPPER FROMIk PRINTING LIKE ` Springiield, Ohio, a corporation of Delaware Application May 2a, 1942-,- serial No. 444,228

' (cms-ss) 7 Claims.

My invention relates to Anew and.A useful improvements in a method for the separation and reclamation of metals and .alloys that make up printing plates and printing cylinders and other articles of e, like nature on which copper and i nickel may have been deposited.

The present application vdeals more particu metal iis especially valuableand scarce-at this time.

The separation and reclamation of the Yand the backing metals from the plates will be mentioned, but the process for the recovery of the nickel forms the subject matter of my application Serial No. 447,582, led June 18,1942.

- As is well known to those skilled in the art, the printing cylindersv or plates of the printing presses are composed of a base electrotype metal consisting generally of an alloy of tin, lead and antimony, then a sheet of tin foil for tinning purposes, after which there is electrolytically de- -posited a layer of copper, over which there isdeposited a layer of nickelfor the sake of hard- After these cylinders or printing plates have been used, they have generally been discarded or stored away, and although various means have beentried for the separation and reclamation especially of the copper, still the processes have been complicated, and the time taken to reclaim the nickel larly with the recovery'of the copper, as this l copper covered a. relatively long period, thus i making the recovery not practical from acommercial standpoint.

One of the objects of the present invention. therefore, is to provide a method for the recoving the copper from the backing material, and

'. alscthe recovery of the nickel, so that thisv copper can again be'made into anodes and then redeposited on new printing plates and the base metall and the nickel also recovered for refuse.

Another one of the objects of the present inery of the base metal and especially for separate.

vention vis to provide a method for the separation and reclamation of the copper which will take but a relatively short time and thus keep down the cost of the said reclamation process.

Still another object of the invention is to pro- 4vide a method especially for the recovery of the cospper inthe used printing press plates, which method will effectively separate the copper from the other metals or alloys making upthe ccmcover the copperfrom the printing plates which consists in removing thenlckel by an electrolytic process; removing the. base by heat; subjecting.

the copper shell also to heat; suddenly cooling; then a. knurling action to .break up the scale; and a mechanical as lwell as a chemical cleansing operation so that the copper can be quickly and readily again used for 'andes for the depositing. of -the copper on new printing plates and cylinders. l With 'these' and other objectsin view, the inventionv consists in certain new and novel steps for carrying outA the method shortly to be oi1t. lined.

embodiment of my invention,

, `Fig. 1 is a small fragmentary section of a printing cylinder or plate afterit has been flattened and is ready to be treated, the tin foil being 'enlarged for the sake of clearness `of 'illusy tration; .f

lliig. 2 is similar to Fig. 1 but showing the nickel as having been removed; Fig. 3 is a view similar to Fig. copper shell remaining with its tin foil now the uppermost position; e

Fig'. 4- is a diagrammatic view of conveyor` rollers, pressure rollers, cleansing bath and means forheating the copper shell or plate on its trip to the storage station; and

QFig. 5 is a fragmentary view showing how the 2 and shows the m.

reclaimed copper shell will appear when oo mpleted.

As heretofore mentioned, inthe method to be outlinedl'. not only recover the copper and the nickel, but also the base material; but the recovery of these is incidental to the recovery of the copper and the recovery of the nickel forms the subject matter of my application Serial 447,582, nled June 18, 1942.

As heretofore mentioned, the printing plates as used in the large at presses and cylindrical printing presses consist of a backing metal, which is an alloy of tin, lead4 and antimony, and designated by the word Base inthe drawing.

In the several views I have shown the plate as being at, ratherthan arcuate, but, ofcourse, in

the recovery of the 'metal by my method, when the plates are of cylindrical form, thecylinders are iiattene as may be seen in the several views.

A sheet of tin foil 2 is shown, which! have exaggerated' in thesev'eral views ior'th'e sake of clearness, j' which tin foil is placed on the rear face of the copper which acts as a tinning agent when the base metal 3 is cast thereon. e

Referring to the drawing showing a preferred- It might be mentioned that in the formation of printing plates there is a wax or lead mold made from an original copper etching and this lead or wax mold is then plated in a nickel elec- .troplatingtank with a nickel deposit of from .001

to .0015 of an inch. The mold with the nickel thereon is then subjected to a copper plating where from .006 to .0012 of copper is plated on back ofthe nickel. Then the mold with its covering of vnickel and copper is removed from the tank and the lead mold stripped away. ',Ihe plate, now of copper and nickel, is cut down to-size of the printing plate and placed in a casting machine, copper side up, and at this stage the tin foil is placed on the face of the copper-. Then the backing metal that is the lead, tin and antimony is cast on the copper, the tin foil acting as a tinning medium.

It has been the general practice to store away these used plates or cylinders, and a number of processes have been devised for separating and reclaiming the metals, but these methods have not come into practical use due to the heretofore relative cheapness of the metals and their plentiplace before the plate is straightened out or afterwards. They are then cleaned with a hot, soapy Water. Y

After the ink has thus been removed, the plate is suspended fromthe anode bar of an electroplating tank (not shown). g

The proper solution and suilicient density of current is used to quickly strip the metal from the outer or copper surface.

I have not shown the tank for the electrolytic stripping solution for the nickel and it might be mentioned that the solution Will contain, in the proper portions, muriatic acid and boric acid in aqueous solution. The boric acid acts as a' suitable buffer medium, and it is possible to strip the nickel from the plate in from three to four minutes.

During the stripping action the plates should be supported by .their respective hangers, the

plates being secured by one corner, and after the Y It might be mentioned here thatwliat little' copper has gone into the electrolyte bath may be precipitated and recovered, but the presentinvention relates to the main body of copper that has not been affected by the electrolytic bath.

' After the printing plates have been treated as heretofore mentioned, they are now composed of 1 a base 4of an alloyof lead, tin and antimony.,

a thin film of tin and a layer of copper.

I next take the plates which are now in the form shown in Fig. 2 and coat the upper or copper surface With' a thin coating of Whiting such as calcium oxide or its equivalent. After the Whiting has been carefully applied, the plates are then placed in a melting pot (not shown) where the temperature is accurately controlled.

The temperature is held as close to the lower range of the melting point of the base metals as possible, as it is not desired to add more heat than is absolutely necessary to make the metal ow easily and it is desirable to keep the oxidization of the antimony and tin to' the very mlntated so that the impurities will go to the top of the pot, while the base metal is poured from the bottom of the pot.

A chemical analysis ofthe reclaimed base metal can be made at regular intervals to maintain the proper ratio of tin, lead and antimony. Of course, the copper plates will be at the top of the molten metal.

The Whiting that was applied to the face of the copper prevents the base metal from adhering to this surface during the melting of the base metal.

The copper plate or shell appears as now shown in Fig. 3 (here againthe tin foil being exaggerated for the sake of clearness of illustration) and I then place this copper shell on the conveyor rollers 6 as seen in Fig. 4.

These copper shells or plates now have a thin coating of thebacking metal that adheres very tightly due to the tinning operation in the making up of the composite plate.

Of course, the tin foil has lost its original form, but it mixes with a part of the base metal and heretofore has been extremely hard to remove. However, by placing the plate on the roller 6 as heretofore mentioned, with the tinning on the upper surface, and by heating the copper shells to a bright red heat, andy exposing the tinned surface-that is, the upper surface, to the air during the heating, I can oxidize the remaining tin land backing. metal and turn it into a hard, brittle scale in the course of from fifteen seconds to two minutes.

To provide the heat, there is shown a plurality of gasjets 1 positioned between the rollers 6 playirgtdirectly on the copper or underl surface of the p a e.

To further assist in loosening the oxidized scale from the copper shell, the shell is advanced beneath a. cold spray, as shown at 8, and this sudden cooling of the hot plate materially assists in also loosening and removing the unwanted oxidized scale.

The plate then continues on its travel and passes between the rst two knurling rollers 9, which tend to bend or corrugate the copper plate, as may be seen in Fig. 5.

After passing through the rst two knurling rollers, the plate then passesI through the second pair of knurling or crimping rollers 9 which are arranged to bend or undulate the metal in' an opposite direction. In ther` words, the small areas are first bent u ardly by the one set of rollers, and then downwardly by the second, and

. this corrugating or bending action further pulverises and loosens the scale of oxidized metal,

Vthus leaving the ,copper relatively clean.

is removed from the plate'by the above-describedcleaning operations.

- Finally the plate moves under a spray jet where it is ag'ain washed to remove the muriatic acid and then drops to a, storage bin I3.

The plates are then dried and-may then be remelted and cast to be again used as anodes for depositing the copper on the base metal,-as heretofore mentioned.

It might be mentioned that one of the critical steps of the method is the applying of the proper heat in a uniform manner to the copper plate, in order to thoroughly oxidize the film of backing metal. If this film is not thoroughly oxidized, it will not separate from the copper during the crimping process of the roller. y However, with the proper application of heat` to the copper, the lead, antimony and tin can be properly oxidized in from fifteen seconds to two minutes. as heretofore mentioned.

From the foregoing it will be seen that I have devised a method wherein all the. metals that make up the printing plates or other similar articles can be saved and reclaimed, the reclamation of the copper beingthe important metal at this time.

It will be seen that the entire method from the scrubbing and flattening of the plates until the time they have passed through the electrolytic bath, melting pot and apparatus mentioned,

consumes but a relatively short time, so that the method is not an expensive one but, on the other hand, relatively fast and relatively inexpensive. g It will be understood that the heating and cooling operations, and the electrolytic action must be watched and regulated, but I have found the method in actual practice to give excellent results and quickly and readily separates the various metals from each other, and especially separates all of the tinning and base metal from the copper plate, sothat the copper can be re meli:ed,v

cast and re-used as anodes with the same effect as if the copper were virgin, rather than reclaimed. l V

It will also be seen that the apparatus may' be built at a. low cost and occupies but a relatively small iioor space:

Finally, it will be understood that by utilizing a conveyor system for the plates as diagrammatically illustrated, in which there is a receivingstation, a cooling station, a knurling station, a tank and a discharge station, the apparatus can be/ watched by a minimum number of workers or operators to thus keep down the'cost of the reclamation. It will, of course, be understood that rather than' having a storage bin as men.-

tioned, a portable truck or other means might' be located under the discharge station so that theA plates after being treated may be rapidly removed for recasting. I l

Having thus described` my invention, what I printing plates made up of a base metal with a coating of copper and nickel thereon, said base metal having a lower melting point than copper, which .consists in electrolytically stripping off the nickel; coating the stripped surface with a Whiting; melting f off the base metal which leaves but .a thin I,coating of the same on one surface of the plate; oxidizing the thin.coating by heating and rapidly cooling the Yplate to change the coating to a scale; distorting the surfaces of the plate in a plurality of minute areas to thus crack and loosen the scale: and removing the loosened scale from said plate.

2. 'I'he vmethod of recovering the copper from printing plates made up of a base metal containing an al1oy-of lead, antimony and tin, and on which has been deposited a layer of copper and nickel, which co ists in electrolytically stripping off the nickel; oating the stripped surface with a Whiting; subjecting the plate to a direct heat of suiilcient temperature to melt the base metal and leave but a thin coating thereof on the-one surface of the plate; subjecting the non-coated surface to heat'from fifteen seconds to two minutes and rapidly cooling the plate by spraying .water thereon to thus oxidize the coating; subjecting the plates to rollers to bend the surfaces into a plurality of hills and valleys and then to further rollers to change the hills into valleys and vice versa to thus thoroughly crack and loosen the oxidized scale from the copper surface, and mechanically and chemically remove the loosened scale from said plate.

3. The method of separation and reclamation of copper from printing plates made up of a base metal comprising lead., tin and antimony, a laye of nickel, and a layer of copper between the baset metal and nickel layer, which comprises thoroughly cleansing the plate;'electrolytlca1ly' stripping the nickel from the surface of the copper layer; covering the stripped surface with whit ing and placing the plate in a melting pot and melting olf the base metal for future recasting; heating the copper plate-by directing a hot flame against the stripped surface to oxidize any film of base metal remainingbn the other surface of the copper plate, subjecting the plate to a cold spray to chill the plate and make brittle the oxidized film; crimping the plate to loosen the oxidized metal lm; subjecting the plate to a cleansing brush and then to a cleansing acid bath; and finally washing the plates with water to remove the acid.

- 4. The method of recovering copper from printing plates made up of a base metal with a coating of copper and nickel thereon. said base metal having a lower melting point than copper, which consists in electrolytically stripping off the nickel; applying a protective coating to the stripped surface, melting off the base metal which leaves but a thin coating of the same on ing by heating and rapidly cooling the plate to change the coating to a scale; distorting the surfaces of the plate in a plurality of minute areas to thus crack and loosen the scale, and reclaim as new and-desire to secure by Letters Patmoving the loosened scale from said plate.

-5. The method of separation and reclamation of copper from printing plates made up of a base metal comprising lead, tin and antimony, a layer of nickel and a layer of copper between the base metal and nickel layer, which comprises thoroughly cleansing the plate, electrolytically stripping the nickel from the surface of the copper layer, covering the stripped surface with vWhiting and placing the plate in a melting pot and antimony which remains on the other surand melting olf the base metal for future recastface ofthe copper plate, then quickly subjecting ing. heating the copper plate by directing a hot the plate while still hot to a cold water spray to name against the stripper surface to oxidize any quickly chill the plate and make brittle the relm of base metal remaining on the other sur- 5 malnlng oxidized lm, crimping the plate to disface of thecopper plate, subjecting the plate to tort and undulate the surfaces of the plate to a cold spray to chill the plate and make brittle thus loosen the oxidized metal nlm on the ppper the oxidized film. crimping the plate to loosen lsurface of the'copper plate. brushing the plate to the oxidized film, and cleaning the oxidized metal remove the sealy film. cleaning the brushed plate iilm from the crimped plate. l0 with acid, and finally washing the plate to re- 6. The method of separating and reclaiming move the remains of the acid bath.

copper from printing plates made up of a base '7. vlin a 4method o'f recovering copper from a metal, comprising lead, tin and antlmony, tocopper plate having one relatively clean surface gether with successive layers of tin, copper and and a coating of a metal on the other surface nickel superimposed on said base metal, which 15 thereof that o xldizes at atemperature lower than consists in thoroughly cleansing the plate, electhe melting point of copper. oxidizingV said coattrolytically stripping the nickel of! the surface -ing by directing a flame against said clean surof the copper layer, covering the stripped surface of said plate, distorting said plate in a pluface with a chalk,lmelting oi the base metal, the rality of small areas to crack and loosen the oxchalk preventing the aforementioned metal from 20 idlzed coating. and removing the loosened coattinning the stripped surface of the copper plate. ing. l heating the copper plate by directing a hot name AXEL E. LUNDBYE. on said stripped surface to oxidize the lead. tin

l thtthe same may co'no CERTIFICATE or CORRECTION. A Patent No. 2,556,529. August 22, 19h14.

AXEL E. ALUNDBYE.,

Y It is hereby certified that error appee.rs in thev printed speci'ficetion of the `above numbered patent requiring correction as follews: Pego li, first coiumri, line li, claim 5, for the word that the s .d Letters Patent s'houd beraad with this correction therein rm to the record of4 the case in thePatent Orifice. Signed and' sealed this 5rd day of Octber, A. D. 19h14..`

Leslie Frazer (Seal) Acting Ce'nnnissioner of PatehtsJ.

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