US1333985A - Method of and apparatus for precipitating copper from hot solutions - Google Patents

Description

F. LAIST.

METHOD OF AND APPARATUS FOR PRECIPITATING COPPER FROM HOT SOLUTIONS, APPLICATION FILED SEPT. 8, 1919.

1,333,985. Patented Mar. 16,1920;

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METHOD OF AND APPARATUS FOR PRECIPITATING COPPER FROM HOT SOLUTIONS.

APPLICATION FILED SEPT. 8 1919. 1 ,333 ,985, Patented Mar. 16, 1920.

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F. LAIST.

' METHOD OF AND APPARATUS FOR PRECIPITATING COPPER FROM HOT SOLUTIONS.

APPLICATION FILED SEPT. 8, 1919.

1',333,985. Patented Mar. 16, 1920.

3 SHEETSSHEET 3.-

' Gum UNITED STATES PATENT OFFICE.

FREDERICK LAIsT, or ANACONDA, MONTANTA.

METHODflF AND "APPARATUS FOR TRECIPIIATING COPPER FROMI-IOT SOLUTIONS. I

Specification of Letters latent Patented D131. 16, 1920.

Application filedSeptember 8, 1919. Serial N0.-'322-;355.

To all whom it may concern:

Be it known that I, FREDERICK LAIs a citizen of the United States, residing at Anaconda,in the county of Deerlodge and State of Montana,-have invented certain new and :useful Improvements in Methods of and Apparatus "for Precip-itating Copper from Hot Solutions, of which the followingis a specification.

This invention relates tothe recovery of metals from solutions and more particularly to the precipitation ofcopper from hot solu tions. As an exampleof this class of inventions may be'mentioned the p-recipitationof copper from hot sulfate solutions with sulfur dioxid.

According to the known practice, the roasted ore, matte or other copper bearing material is leached with an acid solution such, for instance, as 'anacid solution of 1 copper sulfate, and the resultingcopper-enriched solution is impregnated with sulfur dioXid and heated to a considerable temperature in a closed vessel, whereupon copper is precipitated. The acid is thus freed and may be used for leaching further batches of ore.

The process is quite feasible, but itsipracticability is impaired by the fact that the heating of the copper solution in practice is an item ofconsiderable expense, since such solutions are generally rather dilute and seldom contain much more than 1% of copper. As ageneral rule'the higher thetemperature to which the solution is heated, the greater will be the percentage of copper precipitated. 1 a

The present invention comprises an improvement of the process as heretofore carried out and embodies certain novel features which make the operation economical and highly practical.

According to the improvements, the heat remaining after the metal has been precipitated from the solutionis used in a very effective manner to preheat the solution from which the copper is to be precipitated and is thus conserved to a veryconsiderable extent.

This and other features of the improvements will be more clearly understood as the description proceeds reference being had to the accompanying drawing, wherein;

Figure 1 illustrates diagrammatically ape paratus suitable for carrying out the invention;

Fig. Qisa view similar to Fig. 1 with certain modifications; and

Fig. 8 is a diagrammatic view of another modification. J V

Referring to Fig. -1, the numeral 1 indicates a closed precipitating tank having a steam-supply pipe 2, extending some dis tance thereinto asshow'n. The steam-supplypipe 2 is provided with a suitable valve. 8. Near'the top of its conical bottom a, the tank 1 has a. liquor outlet-pipe 5 equippedwith a valve 6, while at the bottom or apex of the conical part 4 the tank is provided with an outlet-pipe 7 for Withdrawal of precipitated metal. The pipe 7 has a suitable. valve 8. I

Near tank 1 is located a closed preheater 9, which may be of any suitable form, but which for convenience is shown as similar in many respectsto the precipitating tank 1 A pipe 10 having a valve 11 supplies steam to the upper part of the tank 9, anda pipe 12 having a valve 13 connects the upper part of the precipitating tank 1 with the preheating tank 9, the outlet of said pipe 12 in the preheater being preferably fairly close to its bottom as shown. Such bottom 14, which may conveniently be conical is provided with a draw-off pipe 15 having a valve 16.

Conveniently near-the preheating vessel 9 and elevated somewhat with respect thereto is a receptacle 17 which may be termed a storage tank. This receptacle is closed and has anoutlet 17 leading to S0, compressor (not shown) for recovery of excess S0,. :It is connected at or near its bottom with the preheating tank .9 by means of a conduit 18' provided with a valve 19. A pipe QOhaving a valve 21 connects'the'top of theprecipitating vessel 1 with the storage receptacle 17, the end 22 of the pipe 20 in the receptacle 1-7 being preferably rather close to the bottom thereof,

Below the levels of the tanks 1 and 9 and the storage receptacle 1-7, there is a heat-interchanger 23, preferably of the countercurrent type illustrated. It may consist'ofya casing inclosing a bank of spaced tubes 24 whose opposite ends open beyond the usual supporting tube-sheets into compartments 25, 26 at 'theends of the casing. As is well under stood, in "the operation of a heat-interch'anger of this type one'ofthe fluids passes from one. of the end compartments to *the other through the tubes, while the other fluid circulates freely in the chamber around the spaced tubes.

One of these end compartments, is shown as communicating with the storage-tank 17 by means of a pipe 27, while the other end compartment 26 is connected by a pipe 23 with a supply-tank 29, preferably elevated sufiiciently to cause the solution therefrom to pass through the heat-interchanger 23 up into the storage-vessel 17. One end of the chamber around the tubes 24:, which chamber is indicated by the numeral 30 in the drawings, is connected by pipe 31 with the bottom of receptacle 32 located beneath or beside the valved outlet 5 of the precipitating vessel 1. The other end of the compartment 30 is shown in communication with a pipe 33 whichleads to the top of a receptacle 31. The elevated supply-tank 29 is provided with a liquid-inlet pipe 35 and the receptacle 3% has at or near its bottom a liquid-outlet pipe 36.

The precipitating operation as carried out in the apparatus described is substantially as follows:

The precipitating tank 1 is filled approximately three-fourths full with the copperbearing solution from which the metal is to be precipitated, such solution being preheated in a manner to be described to ap proximately 125 C. From this temperature, the heating to about 155 C. is completed by means of live steam taken from a boiler plant through the valve 3. Prior to the treatment'with steam S0 is added in the usual manner. The precipitation in tank 1 having been completed and a final temperature of about 155 C. having been attained, the valve 3 is closed and the valve 13 is opened, thus releasing the pressure on the surface of the liquid in tank 1, about 100 lbs. per inch, and causing the liquid to boil. The steam passes through pipe 12 into the solution contained in tank 9. In about thirty minutes an equalization of pressure between tanks 9 and 1 is accomplished and also an approximate equalization of temperature results. What actually happens is that the pressure 'in tank 1 falls from about 100 lbs. per square inch to about 30 lbs. and the pressure in tank 9 rises from zero to 30 lbs. At the same time the temperature of the liquid in tank 1 falls from 155 C. to about 130 (3. while the temperature in tank 9 rises from about 100 C. to 125 C.

This having been accomplished the valve 13 is closed and the wave 21 is opened, permitting the steam, which naturally comes off, to flow into the solution contained in tank 17 which has been raised within a few degrees of the boiling point by passage through the interchanger 23. At the same time, the acid liquor in tank 1 falls in temperature to the boiling point,

or about 100 C. and is allowed to flow into the hot solution storage tank 32 by opening the valve 6. From tank 32 the hot liquor flows through pipe 31, through the jacket 30 surrounding the pipes 24:, in the direction indicated by arrows, and then into the tank 34 whence it may be pumped to the leaching plant (not shown) to be used as leaching solution ona fresh charge of ore. The copper which has been precipitated in tank 1 is drawn off by opening valve 8.

Thevalve 13 is now again opened and at the same time high pressure steam is admitted through valve 11 whereby the solution in tank 9 is forced into the tank 1 for treatmerit. Tank 9 is then recharged with boiling solution from the storage tank 17.

The acid liquor, which is passed from the leaching vats to the tank 29,passes through pipe 28 into the heat exchanger 23 and through the pipes 24 thereof and is thus heated by the hot solution flowing through the jacket 30, as previously described, from about 20 C. to 90 C. The liquor passing from pipes 24: of the heat exchanger to the tank 17 thus has a tem perature of 90 and this temperature is raised, as previously described, by the steam coming from tank 1 to 100 C.

In place of a single preheating tank 9, a plurality of preheating tanks may be employed in series. The pressure in tank 1 may be released down to say 60 lbs, in the first of these tanks, then down to, say 30 pounds in the second of these tanks, and then finally blown off into tank 17.

Fig. 2 shows an arrangement which is generally the same as that shown in Fig. 1.

However, the tanks 1 and 9 are alternately j used as preheating and precipitating tanks respectively. The liquor is alternately drawn from the tank 17 through valves 19 and 19 into tanks 1' and 9. After tank 1 has been used as a precipitatingtank, the valve 13 is opened and the steam allowed to pass into tank 9 to raise the temperature of the liquor therein to 125 C. as previously stated. When the pressure in the two tanks is equalized, valve 13 is closed and valve 21 opened to pass the steam from tank 1 into tank 17 as previously described. The hot liquid is then drawn off from tank 1' into tank 32' by opening valve 6. The tank 1 is then refilled by opening valve 19. The liquor in tank 9' is then treated with steam by opening valve 3". After the treatment is completed, valve 13 is opened to permit the steam to pass into tank 1. After equalization in the tanks has been reached, valve 21" is opened to let the steam pass into tank 17. The hot solution is now drawn off through valve 6" into tank 32".

The recovery of the heat is accomplished principally in ,tWo stages 2'. c. :first :by the utilization of :the liberated steam andthen by the utilization of the hot liquid. While a preheating tank, as described, may be conveniently resorted .to for raising .the temperature .of the .solution coming from the-tank l7vto a point in excess of the temperature at atmospheric pressure, it may obviously be dispensed with and the appato the blowing off of steam directly into the solution. It is, of course, understood that the heat energy of the steam may be transferred to the liquor through coils. In

' fact the character of the devices for transferring the heat energy of the steam and the hot metal-lean liquid to the metal-rich solution to be preheated may be varied in various ways within the scope of the in vention.

The improvement applies equally well to other solutions such as sulfate and chlorid solutions.

I claim:

1. The method of recovering copper which comprises leaching a copper-bearing material with an acid solution, impregnating a charge of copper-rich solution with sulfur dioxid, heating the impregnated solution to effect precipitation of copper and utilizing the heat energy of the steam remaining after precipitation for preheating another charge of metal-rich solution.

2. The method of recovering copper which comprises leaching a copper-bearing material with an acid solution, impregnating a charge of copper-rich solution with sulfur dioXid, heating the impregnated solution to effect precipitation of copper and separately utilizing the heat energy of the steam and of the liquid remaining after precipitation for preheating other charges of metal-rich solution.

3. The method of recovering copper from acid solutions, which comprises impregnating the solution with sulfur dioxid, injecting steam under pressure into the impregnated solution to precipitate copper, and preheating the metal-rich solution with the residual steam of the precipitating step.

4:. The method of recovering copper from acid solutions, which comprises impregnating the solution with sulfur dioxid, injecting steam under pressure into the impregnated solution to precipitate copper,

heating the metal-rich solution with it'llt) re sidual steam of the precipitating step, and

preheatingsaidmetahrich solutioin byvmeans of the metal-lean solution.

5. The method ofrecovering copper from acid solutions, :which comprises impregnating the solution withsulfur dioxid, injecting steam under pressure into the impregnated solution :to precipitate copper, releasing the pressure from the solution and utilizingthe steam given off during-theme lease for heating a n'ietal-rich solution and utilizing the metal-lean I solution for heating the metal-rich solution.

6. In the process of recovering copper from hot acid solutions by impregnating the solution with sulfur dioxid and injecting steam into the impregnated solution, the method ofrecovering the heat from the treated solution, which consists in separately utilizing the residual steam and the residual metal-lean liquid present in the precipitating chamber. after a precipitating operation to preheat charges of metal-rich solution to be subjected to treatment in the precipitating chamber.

7 In the process of recovering copper from hot acid solutions by impregnating the solution with sulfur dioxid and injecting steam into the impregnated solution, the method of recovering the heat from the treated solution, which consists in heat-- ing a new charge of metal-rich solution by means of the hot metal-lean solution remaining from one precipitating operation and then heating the charge by the residual steam incident to a subsequent precipitating operation.

. 8. Apparatus for recovering copper'from hot solutions by impregnating the solution with sulfur dioXid and injecting steam into the impregnated solution, comprising a precipitating chamber, a feed connection for feeding a metal-rich solution to the precipi tating chamber, said feed connection includ ing a plurality of vessels, a controllable connection between the top of the precipitating chamber and one of said vessels for bringing the steam remaining after precipitation into heat-exchange relation with the solution in the feed-connection, and a controllable drain connection leading from the lower portion of the precipitating chamber to another of said vessels for bringing the hot liquid remaining after precipitation into heat exchange relation with the solution in the feed connection.

9. Apparatus for recovering copper from hot solutions by impregnating the solution with sulfur dioxid and injecting steam into the impregnated solution, comprising a precipitating chamber.a feed connection for feeding a metal-rich solution to the precipitating chamber, said feed connection including a plurallty of vessels in series, a con trollablc connection leading from the top of the precipitating chamber into each 01 said vessels and terminating near the bottom thereof and means for controlling the feed section between the two vessels.

10. Apparatus for recovering copper from hot solutions by impregnating the solution with sulfur clioxicl, and injecting steam into the impregnated solution, comprising a precipitating chamber, a feed connection for feeding a metal-rich solution to the precipitating chamber, said feed connection including a plurality of vessels in series, the first of the series being a heat exchanger, a controllable connection leading from the top of the precipitating chamber into each of the other vessels and terminating near the bottom thereof, means for controlling the feed section between the said last mentloned vessels, and a controllable connection between the bottom of the precipitating chamber and the heat exchanger.

in testimony whereof I affix my signature in presence of tWo Witnesses.

FREDERICK LAIST.

lVitnesses BAYARD S. lVIORROW, SELDEN S. RODGERS.

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