US1243681A - Method of reducing sulfids. - Google Patents

Description

n. F. BACON v METHOD OF REDUCING SULFIDS. APPLICATION FILED JAN. I5, 1913.

' 'Patent ed Oct. 23,1917.

N N v \u RAYMOND F. BACON, 0F PITTSBURGH,

orrrcn.

PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGN- -MENTS, TO METALS RESEARCH COMPANY, OF NEW YORK, N. Y., A. CORPORATION OFMAIN'E.

To all whom it may concern: i

residing at Nicholson street, Pittsburgh, Allegheny county, State of Pennsylvania, have invented certain new and useful Improvements in Methods of Reducing Sulfids; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention is based upon the discovery that when the sulfids of silver,

mercury, arsenic, antimony and platinum are caused to reactwith a hydrocarbon, at a suitable and sufficiently low temperature, the metal of the sulfid will be recovered in the metallic state, and hydrogen sulfid as such, utili'zable for various purposes in the art, will also be recoverable.

Among the sulfids above enumerated as feasible for the practice of the invention, it is found that some of them react more readily and at lower. temperatures than others, and that the physical state of the sulfid is an important factor in this regard. In general, it may be said that precipitated sulfids react more readily and completely, under the same conditions, than natural sulfids, and the precipitated sulfids are to some degree approximated in efficiency in this regard by natural sulfids which have first been finely ground or otherwisefinely comminuted'. I

The process is also applicable, as above indicated, to certain minerals containing the available sulfids, as, for instance, cinnabar. Cinnabar reacts quite easily and at comparatively low temperatures, and, when cinnabar is reduced in accordance with the invention, if the temperature is suflicient to volatilize the mercury, the released mercury vapor distils over and may be collected in a suitable condenser.

In so far as the reduction of the metallic sulfids is concerned, it is not necessary to keep the temperature below the dissociation point of hydrogen sulfid. Where hydrogen sulfid is to be produced, however, it should be borne in mind, in controlling the temperature of the reaction that hydrogen sulfid begins to dissociate at about 400 C. and that the dissociation amounts to about 8% at 500 C. and assumes increasing impormn'rnon or nnnocrne sonrrns.

Specification of Letters Patent.

Patented oct. 23, 1917.

Application filed January 15, 1913. Serial No. 742,219,

tance at higher temperatures. It is therefore desirable, in so far as the production of hydrogen sulfid is concerned, to maintain the temperature relatively low, and,

.in general, not to exceed 500 0. So also, inasmuch as the sulfids are reduced in the practice of the invention at temperatures below 500 (1, it would not be economical to proceed at any higher range of temperature. V

The sulfid may be charged into a suitable receiver, which may conveniently have the form and dimensions of an ordinary still, adapted to be heated, as, for instance, ex-

ternally by direct firing, in the usual manner, or internally, and which is provided With the necessary means for admitting the sulfid charge, for supplying the hydrocarbon, and for the I products of the treatment either continuously or intermittently, and also with means for conducting ofi' the hydrogen sulfid to the place of storage, condensation, or use. If the sulfid charged contains a large quantity of moisture, .as, forinstance, in the case of a wet precipitate, the containing vessel should have a sufficient capacity, with respect to the charge, to take care of such foaming as is incident to the operation, or, any su table means may be provided to suppress the foam or to prevent it from removal of the residual rising to too high a-level above the upper surfaceof the charge; as, for instance, one or more air jets of high pressure may be directed upon the forming foam layer so as to break it up and release the imprisoned gases or vapors. So also, in order to prevent the condensation and ceptacle and charge'of any water that has been driven ofl in the form of steam during the operation, the still or receptacle may be provided, in its interior and at the upper part thereof with a suitable insert through which the gases and vapors, including the hydrogen sulfid and steam, may freely pass on their way to the exit pipe of the still and which, by reason of its location, is at such a temperature as to intercept and reconvert into steam any water which, condensing out of the escaping vapors would tend to return to the charge.

When a solid or liquid hydrocarbon 'is employed, it may either be mixed with the sulfid and charged therewith into the receiving vessel or still, or, it may be adreturn to the re- 1 mitted into the upper part of the vessel and permitted to drop upon the heated sulfid. In practice, it is usually preferable to thus admit the hydrocarbon upon the top of the charge, rather than to mix it therewith in the first instance, for the reason that by dropping the hydrocarbon upon the top of the charge, a quantitative reduction of the sulfid can be effected with a lesser supply of hydrocarbon, so as to reduce, and in some instances, to practically avoid the presence in the still at the termination of the operation of any large quantity of hydrocarbon to be thereafter recovered by distillation. It will usually be desirable to employ an amount of hydrocarbon somewhat in excem of that theoretically required for the reaction.

lt is also feasible to practise the invention by showering the sulfid through an atmosphere of hydrocarbon vapor, say vaporized mineral oil; a convenient mode of thus showering the sulfid through the mineral oil vapor may consist, for instance, of a rotatory horizontal or inclined cylinder, suitably heated, and provided with means for admitting the mineral oil vapor at one 1 end thereof and allowing the volatile prodnets of the reaction to take their exit at the other end, and being further provided with longitudinal ledges projecting radially inward and adapted to raise the copper sulfid constituting the charge of the rotary cylinder and permitting it to drop, as will be readily understood.

While, as hereinbefore indicated, the in- 1 Y vention isnot restricted to the use of any particular hydrocarbon, it is found feasible, convenient, and economical, in practice, to use what are known generally in the arts, as hydrocarbon residues, as, for instance, oils from which the lighter and more valuable distillates, such as gasolene, kerosene, and

the lighter lubricating oils have been driven off. The hydrocarbon residues thus obtain able from the natural petroleums and other oils having a similar composition such as shale oils, are entirely adapted to the purpose, and may be specified as illustrative of those which may find ready acceptance for commercial uses; so also, there are available for the uses of the invention naphthalene, and substances which, on heating, give I considerable quantities of hydrocarbons, as, for instance, asphalts and bitumens (natural and artificial) coal tar, water gas tar, wood resins, and resin 011. ,Of course, any of the more valuable hydrocarbon distillates may be used where the question of cost is of less importance.

In the, practice of the invention, it is found that the reduction of precipitated mercury sulfid begins to take place at a relatively low, temperature, somewhere between 50 C. and 100 C. It proceeds more rapidly at higher temperatures, and the process may be conducted to special advantage at temperatures representing the boiling point of the hydrocarbons usually employed,that is to say, temperatures ranging from 300 C. to 360 0., which will represent approximately the usual commercial temperatures. Inasmuch as the dissociation of hydrogen sulfid begins at about 400 C. and becomes increasingly important at higher temperatures, it will be preferable to restrict the temperatures accordingly permitting them to rise above say 500 so that there may be no material loss in the recovery of the hydrogen sulfid where that recovery is of particular importance, as will usually be the case. I

In the accompanying drawing'is illustrated apparatus of a type adapted for the practice of the invention although it-will be understood that the illustrationis merely not I representative of many arrangements which nation of the reaction period, it may be placed upon trunnions, as indicated, so lo cated with respect to the closable door 9 that the solid products of the reaction may be discharged into any suitable conveyer atthe end of the reaction. lhese solid products of the reaction will consist mainly of the carbon of the. decomposed hydrocarbon associated with the reduced metal, unless the latter has been volatilized and distilled OK in the operation. The carbon thus associated with the metal may be separated therefrom in any suitable or convenient manner, or, if desired, it may be used as the fuel or a part of the fuel for melting the metal.

E indicates a suitable receptacle for supplying the hydrocarbon to the reaction vessel orv still D. The sulfid to be reduced will be charged through the closable door 9. When a wet precipitateis used or when the sulfid is otherwise in a moist condition, so that the formation of foam will be an'incident of the operation, high pressure air jets i may be connected withthe still, as indicated, and may be supplied with air in any suitable ,manner, as, for instance, by the pump J So also, when the insert hereinbefore referred to conveniently consist of a structure 70 of aluminum or other suitable material, adapted to be raised to a sufficient heat by the escaping hydrogen sulfid and accompanying vapors on their way to the exit pipe 0 of the vessel D, whereby, as hereinbefore explained,

is employed, it may course, be understood that the several pipes serving the a paratus may be provided with suitable regu shown, and with suitable flexible connections and couplings to permit the tiltingof the vessel D; when desired.

What I claim is":

1. The method of reducing the sulfids of silver, mercury, arsenic, antimony and platinum, which comprises reacting upon the sulfid in a non-molten condition to reduce it to metal by means of ahydrocarbon and in a non-oxidizing atmosphere; substantially as described.

2. The method of reducing the sulfids of silver, mercury, arsenic, antimony and platinum, which comprises reacting upon the sulfid in a non-molten condition to reduce it to metal by means of.,a hydrocarbon in a non-oxidizing atmosphere and at a, relatively low temperature; substantially as described.

3' The method of reducing the sulfids of silver, mercury, arsenic, antimony and platinum, which comprises reacting upon the sulfid in a non-molten. condition to reduce it to metal by means of a hydrocarbon at the boiling point of said hydrocarbon; substantially as described,

4. The method of reducing the sulfids of silver, mercury, arsenic, antimony and platinum, which comprises reacting upon the sulfid in a non-molten condition to reduce it to metal by means of a hydrocarbon at a temperature not above 500 0.; substantially as described.

5. The method of reducing the sulfids of ating or controlling cocks as si lver, mercury, arsenic, antimony and platinum, which comprises reacting upon the sulfid in a non-molten condition by means of a hydrocarbon under conditions adapted to duction. of sulfid and the formation of hydrogen sulfid; substantially asdescribed.

7. The method of reducing the sulfids of silver, mercury, arsenic antimony and platinum, which comprises dropping a hydrocarbon upon a heated body of the metallic sulfid in a non-molten condition, under con ditions adapted to reduce the sulfid to metal; substantially as described.

8. The method of reducing the sulfids of silver, mercury, arsenic, antimony and platinum, which comprises dropping a liquid hydrocarbon upofixa heated body of the me-- tallic sulfid in the form I under conditions adapted to reduce the sulfid to metal; substantially as described.

In testimony whereof I aifix my signature, in presence of two witnesses.

RAYMOND F. BACON.

Witnesses:

M. A. BILL, VINCENT SARAREBE.

of a precipitate, and

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