US1322091A

US1322091A - James a

Info

Publication number: US1322091A
Authority: US
Publication date: 1919-11-18
Anticipated expiration: 1936-11-18

Description

UNITED STATES, PATENT OFFICE,

FRANK G. BREYER, OF PALMERTON,PENNSYLVANIA, JAMES A. SINGMAS'IEE, OF

BRONXVILLE, NEW YORK, AND ALBERT E. HALL, 'OF PALMEBTON, PENN- SYLVANIA, ASSIGNORS TO THE NEW JERSEY ZINC COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

PRODUCTION OF METAL OXIDS OTHER COMPOUNDS OF METALS.

No Drawing.

To all whom it may concern:

Be it known that we, FRANK G. Banner, a citizen of the United States, residing at Palmer-ton Carbon county, State of Pennsylvania, JAMES A. Smomas'rna, a citizen of the United States, resldmg at Bronxvllle,

\Vestchester county, State of New York,- and ALBERT E. HALL, a citizen of the United States, residing at Palmerton, Carbon county, State of Pennsylvania, have ini'ented certain new and useful Improvements in the Production of Metal Oxids and other Compounds of Metals; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the artto which it appertains to. make and use the same.

This invention relates to the production of metal oxide or other compounds of metals volatilized by the l/Vethcrill process.

Metallic oxids, such, for example, as zinc oxid and loaded zinc oxid. as well as other iompoundsof metals volatilized by the Wetherill process, such, for exam le, as basic lead sulfate or sublimed lead have heretofore been more or less extensively produced by the so-called Wetherill process.

In speaking of metals volatilized by the VVetheiill process, we intend to describe and cover such metals as are volatilizable at the temperatures attainable in the Vetherill process, and for the sake of brevity, we shall hereinafter designate these metals as Volatilizable metals. In the case of certain of such metals, the final or desired compound or compounds thereof are the result of a sequence of actions in which the metalliferou",

materials of the charge are reduced, the reduced metal yolatilized and then oxidized or otherwise compounded, while in other cases a metal compound may be directly volatilized, with or without. subsequent 0X1- dation or compounding. o

By the expression Wetherill process as we have used the same herein, is'tobe understood the furnacin'g step'of the process for producing metal oxide or other compounds of volatilizable metals in which a charge of the metalliferous' material mixed with a reducing agent and spread. on an ignited bed of fuel is subjected to a combustion supporting blast or draft and Specification of Letters Patent;

Application filed August 1, 191a. Sena-m. 314,721.

brought to a sufiiciently high ten'iperature to reduce the metalliferous materials and volatilize the reduced metal or metals (and (or) to volatilize a metal or a metal cont: pound or compounds) without bringing the charge to a condition where it becomes impervlous to the blast or draft, the entire charge being supported ona furnace hearth or grate' designed to hold it without letting part drop through, and

any considerable the work-oil material being discharged as a clinker or sinter. The furnacing step is independent of the subsequent treatment of the laden furnace gases and of the collection of the metal compound or compounds.

As a typical example of the Wetherill process, as heretofore usually practised, we

will briefly describe the customary procedure in the commercial production of zinc oxid, including leaded zinc oxid. -The fur-. nacing step is generally carried out. in a furnace having a broad expanse of horizontal grate or hearth roofed over with an arch, and associated with appropriate instrumentalities for permitting the passage therethrough and into the charge, by either a blast or draft, of a combustion supporting gas. It is customary to first charge upon the furnace grate or hearth a layer of buckwheat anthracite coal (which is thereupon ignited, usually by the residual heat of the furnace) and by means of a forced blast or with the finely divided zinkiferous (or zinkiferous and plumbiferoi'ls) material,-

such as zinc silicate, roasted zinc blends, roasted so-called mixed sulfids of zinc and lead, spelter retort residues, or other reducible zinc-containing or zinc-andlead' containing material at the disposal of the.

operator. 3} The forced air draft is continued, and, when the familiar flames of greenish tint, known as zinc candles, begin to maketheir appearance above the upper surface #0 ,theeharge, indicating that I the recluctionf.-and volatilization of the zinc and its oxidation to the form oi fame is well under way, the products of combustion carrying the zinc oxid fume and other. volatilized metallic compounds are conveyed through the customary cooling flues, etc., to tlfie ba -room wherein in a cooledcondition, t e

intd the atmosphere, leaving the fume collected in the interior of the bags, from which it is removed at convenient intervals.v The furnace operation is continued until the production of fume therefrom in appreciable quantity ceases, whereupon the residual charge which is, to a large extent, sintered together, is broken up by long-handled rabbles and pried up and lifted or scraped out through the furnace doors into a receiving pit, or the like, preparatory to the starting of a new operation. The coal or other carbonaceous material of the charge serves the two-fold purpose of furnishing a reducing agent for effectin the reductlon of the metalliferous materiais of the charge and of furnishing, by com ustion, the necessary degree of heat to bring these materials to the reducing temperature characteristic of the process.

As thus ordinarily practised, the abovedescribed furnace operation is attended with certain defects interfering with its full efliciency. Prominent among these defects is the inevitable tendency to the formation of blow-holes or craters at various regions of the charge. These blow-holes represent severally the paths of least resistance for the blast in its passage through the charge and to the extent to which they develop in p the progress of the operation they interfere with the uniform distribution of the air in its upward passage and produce hot, spots representing excessive temperatures as comared with other regions of the charge.

rom time to time, the workmen endeavor to eliminate these blow holes or hot spots, as far as is feasible, by rabbling the upper surface of the charge, thereby filling in the blow holes or breaking up their continuity;

but in spite of the palliative effect of these expedients (which, moreover, consume considerable of the workmans time and attention), it is im ossibl'e to obtain uniform working conditions throughout the entire extent of the charge; so that there is not only waste of fuel, and the production 10- cally of higher temperatures than is ,desirable, but the residues taken from the furnace at the termination of the operation contain.

eisen furnace, it interferes to a greater, or-

ter through the bags and pass offless extent with-the normal furnace operation and tends to collect in and obstruct the spiegeleisen furnace flues.

A further defect of the above-described furnace'practicevis that the forced draft, which is employed under relatively considerable pressure, tends to project into the free space above the charge more or less dust, particularly in the region of the blowholes referred to, and this dusting is further aggravated by the rabbling operations; consequently, in addition to the metallic fume, the products of combustion carry with them from the furnace a notable proportion of dust in the form of fine particles of unreduced ore, carbon, ash, and the like, which tend to contaminate the fume proper-and damage its color and marketability.

There are, furthermore, certain requirements of the practice of the Wetherill rocess as heretofore conducted which hamper the operator in the selection of the qualit and size both of the coal and of the zinki erous material employed in making up the charge. Thus, the requirement that the charge shall be sufficiently permeable for the passage of the air, necessitates the use of a mixture of coal and zinkiferous material of a fairly coarse "grader Serious difficulties are encountered in the use of the smaller sizes of buckwheat coal; and only a fractional part of the zinkiferous constituents of the charge can consist of such extremely finely-divided materi s as flotation concentrates, zinc precipitate flue-dust containing zinc, or the-like. Q

The present invention is designed to improve the practice of the Wetherill process, particularly in the respects noted. .That 1s to say, to obtain a more uniform distribution of the combustion supporting as on its .way through the charge; to lower t e resistance of the charge to the passage of the gas; to avoid the formation of blow holes or hot 5 ots; to minimize the contamination of the ume by dust; to increase the permissible quantity of the working charge and consequently the amount of metalliferous material treated in a given time period; to obtain a more complete extraction of the volatilizable metal values and a saving of fuel per unit of metalliferous material present; to eflectively em loy cheap coal of extremely small mesh an coal of such low grades as colliery washings, coke breeze, and the like; and to freely utilize metalliferous material of any degree of fineness, including flotation concentrates, finely pulveru- .lent ore, metalliferous precipitates, flue dust, etc.

For the attainment of the improved results referred to, we have radically modified the present commercial practice of the Wetherill process. Thus, for the initial step of charging the grate bottom or hearth coal below the No. 3 buckwheat size,such

pressing finely divided coal, suitable binder (preferably of the usual oxid furnace with a layer of fine ignition fuel, we have substituted a layer or bed of ignition fuel in the form of briquets. We have found, in actual practice, that it is feasible to employ as the ignition or bed fuel, briquets prepared by comtogether with a the concentrated waste sulfite liquor of the sulfite paper pulp industryfiyand that the coal appropriate for the purpose may consist of the cheaper and smaller grades, as, for instance, anthracite as No. 4 buckwheat, colliery washings (dirt coal or dust coal), coke breeze, etc. We have found that, for this ignltlon or bed fuel, it is suitable to employ briquets of such size and shape as ,duce the resistance to the combustion supporting gas, and nevertheless to supply such a substantially uniform sub-stratum for the support of the superposed working charge as to give free access and practica ly equal distribution of the gas thereto. Thus, the

to materially reignition or bed fuel briquets may be made 9f a form approximating two pyramids havng a common rectangular base of say 1% inches on each side, the thickness of the briquets from the apex of one pyramid to the other being say 1% inches. In general,

' the fuel briquets should be. of substantially bution of the ignition uniform size, and preferably of such shape that theyroll or tumble easily over one another. We have found the so-called pillow block, eggette, rounded pillow block, overstufl'ed pillow, and similar shapes well suited to the purposes ofthe invention. We have ascertained that when, instead of the usual layer of buckwheat anthracite coal, alayer or bed of these fuel briquets is charged upon the grate bottom or hearth of the usual oxid furnace as ignition fuel, the briquets will become ignited by the residual heat of the preceding charge and that theymay then be brought to well developed'combustion, the Working charge may be supplied, without substantially disturbin the orginal distriiriquets, and, consequently, with the preservation of the fairly uniform gas passages which the i ition briquets provide over the entire sur ace of the hearth for the upward passage of'the blast into. the working charge. In some instances, such a percentage of metalliferous material may be incorporated in the ignition briquets as may be tolerated without substantially interfering with their normal function, and to the extent to which this is permissible, the ignition briquets will add a reducing function to their normal ignition function, i

A second, characteristic feature or the invention consists in making up the working (that is to say, the re- 7 the anthracite dust or slush coal,

without briqueting the reducing agent charged withit; or by briquetingthe reducing agent and not briquet'ing the metalliferous material .or by briquetmg the reducing agent and briqueting the metalliferous material separately therefrom; or, preferably by briquetin e, mixture of and of t ef'inhtalliferorm material. These briquets may be made of the same shape and dimensions as the fuel briquets hereinbefore referred to, and by the employment ofan'y suitable binder, such as the conceintrated wastesulfite liquor described. The -reducing agent employed may be of any suitable kind, but one of the marked advantages of the briqueting is that it permits, as we have ascertained, the effective and economical use of reduction coal of the cheaper grades and finer mesh, such as anthracite coal of finer mesh than No. 3 buckwheancolliery washings, coke breeze, and the like,

A. typical procedure, in the manufacture of zinc oxid or leaded zinc oxid, for the pros duction of the working charge briquets made from the preferred mixture of reduction coal and zinkiferous or zinkiferous and plumbiferous material is as follows:

The reduction coal (as, for instance, anthracite dust or slush) which usually averages from 65-7 which usually has a; moisture content of about 10%) is placed, together with the sulfite liquor, in a revolving mixer of the kind employed for the mixin of concrete and, after a short period of mixing, the zinkiferous (or zinkiferous and plumbiferous) material is added, and the mixin operation then continued for a further period of three minutes ormore. Thus,.for-800 pounds of 67 po'unds of concentrated Waste sulfite liquor of 30 Baum is employed, and the metalliferous material added may, for example, consist suitably of 960 pounds of finely crushed zinc ore averaging say 20% of zinc oxid and'l6% silica, together with 480 pounds of so-called dust ore averaging say 23% of zinc oxid and 8 to 9% silica,these ores of carbon (and being, in this instance, mixtures consisting when the material is fed into'the pans of thd rolls from above, it is molded into briquets havin the shape and dimensions hereing of heavy sheet iron and the bottoms of J; inch wire mesh. In these baskets, or in similar receptacles, we dry and bake the briquets, as, for instance, by mounting the baskets filled with briqi'ets upon buggies carrying say twelve baskets in four tiers of three baskets each, which are then pushed into a tunnel drier of the direct coal-fired type. The briquets remain in the drier from one to two hours, at a temperature of approximately 200 C. dependent upon the rate of firing. The dried briquets are then removed from the drier, cooled and stored, under cover, for subsequent use. This drying and baking of the briquets is of service to impart to them the desirable amount of resistance to crumbling and breaking, so that they may be freely subjected to the rough handling incident to storin them, conveying them to the furnace, and incident to charging them into the furnace'either by hand or otherwise. and so that they may likewise substantially maintain their form during the period that they are giving ofl' their volatilizable metals in the furnace.

While some of the advantages of the invention may be attained by briqueting either the reducing agent or the metalliferous material (or both of them) separately, our preferred practice as above noted, is to make the briquets of a mixture of the reducing agent and the'metalliferous material. So also, while the working charge, partly or wholly briqueted, may'be used in conjunction with an ignition layer of fine anthra cite coal, we prefer to use briqueted ignition fuel in conjunction with a briqueted working charge made up of a briqueted mixture of reducing agent and metalliferous material.

Thus, we have found that when, as in our preferred practice, the working charge, in-

the form of briquets made up of a m xture of' metalliferous material and reducin agent, is charged upon a layer of bed fue briquets of like shape and ,dimensions, all of the advantages hereinbefore recited as incident to the invention are present 'In other words, the supplying of the working charge of briquets upon the sub-stratum of well ignited ignition-or bed fuel briquets in full combustion builds up within the furnace a total charge of such low resistance to the upward passage of the combustion supporting gas, that the pressure of the blast in the ash pit may be very materially lowered; or, in some cases, it may be supplanted by the suction efi'ect of the ordinary exhaust fan employed in the \Vetherill process for withdrawing the fume from the furnace, this exhaust sufiicing to pull through the charge a sufiicient volume of gas appropriate for the operation.

The process proceeds, wlthout the production of craters or hot spots and with an even distribution of the combustion supporting as over the entire extent of the char c. It is also found that the reduction an -(or) volatilization of zinc, lead, and other volatilizable metallic compounds, as well as the subsequent oxidation and recovery of fume, proceed more completely than in the here- "tofore customary practice of the Wetherill process, and that the residues show a materially lessened loss of volat-ilizable metal values.

As a typical instance of the pract1ce of the invention, in the roduction of zinc oxid, 900 pounds of bed uel bri uets (which may consist entirely of dust coal) are spread out as evenly as possible upon an oxid furnaceygrate of 111 square ft. area. These entit es are then ignited by the residual'heat of the furnace from a former operation, and when they have reached a good yellow heat, we charge upon them 8,000 pounds of briquets made from the m xture of reducing coal and zinkiferous materlal.

A much lighter blow is used, as the process proceeds, than with the heretofore usual Wetherill process charge. The res dues are withdrawn in from 6 to 12 hours, the 8 hour period usually 'ving the best results. The same number 0 operators is used for wlthdrawing the residues as for the heretofore that for the samelabor the charge treated may b the practice of the invention be increase one-third. It is also found that the clinker adheres with very much less tenacity to the furnace walls, so that the exertion required for breaking up the clinker and removin it from the furnace is correspondin 1y ess arduous.

e have 'hereinbefore referred to the in- .creased capacity of output incident to the".

invention; and, in this connection, we may state that in the preferred practice of the in,

expenditure of fuel, to obtain a higher extraction of'volatilizable metal values (leaving less volatilizable metals in the residue) than in the heretofore customary Wetherill process practice, and that for a furnace run of the same time-period normally employed in working oil the charge of the usual oxid furnace, we have been able as herein-before particularly noted, to treat a briqueted charge containing as high as one-third more of metalliferous material than is contained in the heretofore customary Wetherill process working charge.

It will,- of course, be understood that the specific examples of typical means of practising the inyention are to be understood as illustrative of its practical ap lication, and that they may be widely varied without departing from the intended scope. of the invention as more broadly set forth in the general description and in the claims hereunto annexed.

While we have hereinbefore specifically described the invention by reference to the production of zinc oxid, including leaded zinc onid, we Wish it to be understood that the invention is applicable to the production.

I of other metal compounds of the volatilizable metals. In particular, we contemplate the production oi basic lead sulfate or sub limed lead by the method of the invention. 8U

ln general, the procedure for the production of sublimed lead is substantially the same as hereinbefore described, substitut- Elli all

lid

.till

ing, of course, an appropriate plumbiferous material for the. zmlrlferous material.

Thus, for example, the bed fuel or the work.

ing charge or both may be briqueted in the manner hereinbefore described and supplied to the turnace hearth in the form of briquets. The working charge consists of a mixture of finely divided galena or native lead sulfid and carbonaceous material or other suitable reducing agent, preferably briqueted as hereinbefore described. The

working charge is spread on the ignited.

layer of bed fuel briquets and upon reaching thu reaction temperature, the lead sulfid is reduced and (or) volatilized and subsequently oxidized to lead sulfate and lead o-xid thus forming the so-called basic lead sulfate.

The efiluent contain-in the sublimed lead is Withdrawn from the rnace and the metallic product collected in any appropriate manner. As the source of plumbiferous material, we may use a highgrade cl native lead sudfid suitably crushed and jig-god to free it from accompanying gangue'material, or we may use lea sullid concentrates, such as flotation concentrates, or other appropriate plumbiferous-containing material. with proper additions of sulfur in the form of pyrite, galena, brimstone or other suitable sulfur-carrying agents, whenever there is a laclr of sulfur in the charge to properly sulfate the fume.

What we claim is.:-'- 1. In the production by the Wetherill process of metal oxids or other compounds of volatilizable metals, the step of supplying the bed fuel to the furnace hearth in the form of briquets, substantially as described.

2. In the production by the Wetherill process of metal oxids or other compounds of volatilizable metals, the step of supplying the bed fuel to the furnace hearth in. the

form of briquets, said bri'quets containing a percentage of metalliferous material; sub stantially as described.

\3. In the production by the *Wetherilb process of metal oxide or other compounds of volatilizable metals, the step of supplying in the working charge briqueted metalliferone material; substantially as described.

l. In the production by the Wetherill process of metal oxids or other compounds of volatilizable metals, the step of supplying in the working charge briqueted reducing vmaterial; substantially as described. I

In the production by the 'Wetherill charge briqueted metalliferous material;

substantially as described.

' '6. In the production,- by the lZVetherill process of metal oxids or other compounds of volatilizable metals, the step of supplying the bed fuel in the form of briquets, together with the step of supplying in the Working charge briqueted reducing material; substantially as described.

8. ln the production by the Wetherill process of metal oxids or other compounds of volatilizable metals, the step of supplying the bed fuel in the form of briquets, together -with the step ct supplying in the working charge a briqueted mixture of metalliferous material and reducing agent; substantially as described.

9. In the production by the Wetherill process of metal oxide or other compounds of volatilize-hie metals, the step of supplying the bed fuel in the form of briquets, said briquets containing a percentage ofmetalliferous material, together'with the step of supplying in the working charge briqueted metalliferous material; substantially as described. I

10. In the production by the Wetherill process of metal oxide or other compounds of volatilizable metals, the step of supplyin the bed fuel in the form of briquets, saic bri nets containiea-a ercentaae of metall supplying v 11. In the production by the Wetherill process of metal oxids or other compounds of volatilizable metals, the step of supplyin the bed fuel in the form of briquets, sai briquets containing a percentage of metalliferous material, to ether with the step of supplying in the wor 'ng charge a briqueted mixture of metalliferous maternal and reducing agent; substantially as described.

12. In the production of sublimed lead by the WVetherill process, the step of supplying the bed fuel to the furnace hearth in the form of briquets; substantiall as described. 13. In the production of su limed lead by the We'therill process, the step of supplying the bed fuel to the furnace hearth in the formof briquets, said briquets containing a percentage of plumbiferous material; substantially as described.

14. In the roduction of sublimed lead by the Wetheril process, the step of supplying in the working charge briqueted plumbiferous material; substantially as described.

15. In the roduction of sublimed lead by the Wetherilfprocess, the step of supplying in the working charge a briqueted mixture of plumbiferous material and reducing agent; substantially as described.

16. In the production of sublimed lead by theWetherill process, the step of supplying the bed fuel in the form of briquets, together with the step of supplying in the working charge briqueted :plumbiferous material; substantially as described.

17 In the roduction of sublimed lead by the Wetheril process, the step of supplying the bed fuel in the form of brlquets, together with the step of supplying in the working signatures.

charge a briqueted mixture of plumbiferous material and reducing agent; substantially as described.

18. In the production of sublimed lead by the Wetherill process, the step of supplying the. bed fuel in the form of briquets, said briquets containing a percentage of plumbiferous material, together with the step of supplying in the working charge briqueted plumbiferous material; substantially as described.

19. In the roduction of sublimed lead by the Wetheril process, the step of supplying the bed fuel in the form of briquets, said briquets containing a percentage of plumbi-ferous material, together with the step of supplying in the Working charge a briqueted mixture of plumbiferous material and reducin agent; substantially as described.

20. n .a process for volatilizing and oxidizing metal values involvin of air into a bed containing the metal-bearing material and combustib e material under conditions which will leave the worked-off char e as a clinker and which will produce a v0 atile fume, the step of supplying at least part of the charge in the form of briquets; substantially as described.

21. In the production of sublimed lead in. volving the blowing of air into a bed con,

I tainin the metal-bearing material and com- FRANK G. BREYER. JAMES A. SINGMASTER, ALBERT E. HALL.

the blowing I