US838716A - Electroplating apparatus. - Google Patents

Description

" No. 838,716. v PATENTED DEC. 18', 1906. I

W. s. HUTGHINSO'N. BLEGTROPLATING APPARATUS.

APPLICATION FILED JULY 29.1906.

WILLIAM SPENCER HUTUHINSON, OF BOSTON, MASSACHUSETTS.

ELEOTROPLATI NG APPARATUS.

Specification of Letters Patent. I

Patented Dec. 18,1906.

Application filed July 29,1905. Serial to. 271,812.

To all whom it may concern:

Be it known that I, WVILLIAM SPENCER HUToHINsoN, a citizen of the United States, and a resident of Boston, in the county of Suffolk and State of Massachusetts, have invented new and useful Improvements in Electroplating Apparatus, of which the following is a specification.

My invention relates to electroplating apparatus, and it consists of a novel combination of instrumentalities for recovering the valuable metallic constituents used in electroplating solutions. In gold-plating, for instance, the articles to be coated carry with them adherent to their surfaces a consider able quantity of the plating solution, and as it is essential that this plating solution be thoroughly rinsed from the plated article it is and has been the practice to immerse the plated articles in an abundant stream of water, which removes from them the adherent solution. This practice involves two elements of waste. First, the solution itself is carried away in such a dilute condition that it is practically impossible to recover from it the matter in solution, and, second, the establishment where the plating is carried on uses a disproportionately large quantity of water for washing purposes and usually has to pay for this waste according to the showing of a water-meter.

In the drawings hereto annexed, which show an apparatus embodying my inventions and improvements, Figure 1 is a vertical longitudinal section on the line 1 1, Fig. 2, of the solution-recovering device; and Fig. 2, an end view of a typical plating equipment with my recovering apparatus incorporated therein.

A represents the plating vessels or tanks, wherein the metal articles are immersed in order to be electroplated, say, with a superficial film of gold. The gold solution-say cyanid-adheres to the plated articles when the plating is completed, and they are lifted from the plating tanks A. The platingtanks A are arranged in two rows, and between them I erect the rinsing-tank B. This rinsing-tank is divided by partitions 6 into compartments of suitable number, as B B B B. Each partition I) terminates at a level slightly below the top of the rinsingtank B, so that water may flow progressively from' one compartment to another and finally from the last compartment through a spout E, which communicates with the first of a series of Zinc boXes C. I/Vater is sup plied to the rinsing-tank B from a suitable spigot D. As the plated articles are rea direction which is the reverse of that of the flow of rinsing-water from spigot D to outlet.

E. The water in the compartment B in the normal progress of rinsing successive lots of plated articles contains a moreconcentrated solution of the plating liquid than the com partment B and the same progressive relation persists through the successive com partment 13. Furthermore, as the plated articles are shifted from one compartment of the rinsing-tank to the other in the direction named they carry a smaller and smaller proportion of valuable solution. The relation between quantity of solution carried by the plated article and the strength of the rinsing iquid is thus practically maintained. It has been foundin practice that plated articles may be verythoroughly rinsed by this progressive method with the employment of a very small quantity of water in circulation, and the final washing in a stream of water may be either wholly dispensed with or greatly reduced as to time and water quantity. In the instance used for illustration, where gold cyanid solution is rinsed from the plated articles, the recovering-boxes C are filled with zinc shavings or powered zinc, through which the rinse-water percolates progressively from boX to boX and finally from the last boX in the series to the waste-pipe D. The zinc in these recovering-boxes is occasionally removed and the valuablemetal deposited by reaction therewith recovered.

In actual practice it has been demonstrated that a combined rinsing and recovering apparatus such as above described will pay for its cost several times over in a single year and that, moreover, the rinsing operation is much easier to carry on than it is by the method heretofore adhered to.

It may be found that under some conditions the liquid delivered from the first rinsing-compartment, as B may not be a sulficiently-concentrated solution to be recovered by chemical deposit in the recoveringboxes in the most advantageous manner. For instance, it has been found that under some conditions the zinc in the recoveringboxes C has deposited upon it a film of gold plate, which is not the form best suited to final recovery. As a precautionary measure, therefore, and one which I recommend to be used in all instances, I provide an enrichenriches the rinse-water solution so that the chemical reaction in the recovering-boxes results in the disintegration of the Zinc and the formation of a slime or mud, from which the gold can very readily be extracted.

What I claim, and desire to secure by Let- 'ters Patent, is

1. In an apparatus of the character described, the combination of a rinsing-tank subdivided into a series of compartments, an inlet for rinsing fluid at one end of the series,

an outlet, an enriching vessel communicating with the outlet end of the series of rinsing-tank compartments comprising means for enriching the rinse solution, and a recoving apparatus communicating with the outlet from the rinsing-tank.

2. In an apparatus for the recovery of gold from plating solutions, the combination of the rinsing-tank subdivided into a series of compartments, an inlet for rinsing fluid at one end of the series, an enriching vessel atthe other end of the series, and means therein for supplying fresh cyanid to the rinse solution, an outlet from the said enriching vessel and a series of zinc boxes communicating with the said outlet.

Signed by me at Boston, Massachusetts, this 25th day of July, 1905.

WILLIAM SPENCER HUTCHINSON.

Witnesses:

JosEPH T. BRENNAN GRACE E. GrBBoNs.

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