US65914A - hughes - Google Patents

Description

2 Sheets -Sheet 1.

J. HIUGHIEJS= FURNACE FOR BURNING PYRITES FOR THE MANUFACTURE OF SULFURIC ACID AND OTHER PURPOSES.

N0. 65,914. Patented June 18; 1867.

2 Sheets-Sheet 2. J HUGHES. FURNACE FOR BURNING PYRITES FOR THE MANUFACTURE OF SULPURIC ACID AND OTHER PURPOSES.

No. 65.914. Patented June 18, 1867.

Quint tatts @strnt firs JOHN HUGHES. OF EDGEWATER, 'NEW YORK.

Letter Patent No. 65,914. dated June 18, 1867.

IMPROVED FURNACE FOR BURNING PYRITES FOR THE MANUFACTURE OF SULP HDRIO ACID AND FOR OTHER PURPOSES.

dip Srgetulc more in llitSt littus flaunt ant making out at the same.

TO ALL WHOM IT'MAY CONCERN:

Be it known that I, JOHN HUGHES, of Edges-titer, in the county of Richmond, and State of New York,

have invented a ncw and useful Improvement in Furnnesfor Burning Pyrites Without the Aid of Fuel; and I do hereby declare that the following is a full, clear, andexaet description thereof, which'will enable others skilled in the art to make and use the same, reference being bad to the accompanyingdrawings, forming part of this specification, in whichi Figure 1, Sheet 1, is a vertical section of a block of furnaces of my improved plan 'of construction taken in the line 2: :c, fig. 3, sheet 2.

Figure 2, a horizontal section of the same taken in the line yy. Figure 3, Sheet 2, a front vi'ew of 'a block of my improved furnaces, with'the outer wall removed fromone furnace, showing its interior in vertical section.

Figure 4, a detached view of the door-plates of a single furnace.- Similar letters of reference indicate like parts. i My invention relates to anew and improved plan of construction of furnaces or kilns for b'urningiron or other pyritcs to expel the sulphur, either for the purpose of utilizing it in the manufacture of sulphuric acid or for extracting the metals which may be associated with the mineral.

The pyrites are burnt in my improved furnace without the aid of fuel to maintain combustion, after the tire has been started with coke or other suitable kindling stuff, by the ignition of the sulphur alone. The pyrites are fed in at the top, and the desulphurizod mineral is withdrawn from the bottom.

Furnaces for burning iron pyrites without the aid of fuel are not novel, but their plan of construction difi'ers materially from that of my invention, and they differ essentially in the results of their operation. The nearest in their plan of construction to my improved furnace are those employed at. various chemical works at St. Helens, Wiggin, Manchester, and other places in Great Britain, for the manufacture of sulphuric acid.

These perpetual-burning furnaces are described by Professor Muspratt, in his Chemistry as applied and relating to the Arts and Manufactures, page 1024, volume 2, from which are made the following extracts:

The structure of a pyrites kiln is shown in Figures 576, 577.

In Figure 577 the pyrit'es is shown as enclosed on two sides by two sloping walls, the back and front walls being vertical.

The mass of pyrites rests on iron bars in the same manner as an ordinary coal fire; the air rushes upfrom what, in an ordinary furnace, would be the ash-pit, and wends its way through the crevices and interstices of the mass tofeed the combustion.

Sometimes the combustion goes on at a rate so rapid that the pyri'tcs become fritted or enter into a semifused state. Sometimes the whole mass gets fused together, In such acase the brick closure is removed for the purpose of introducing a crow-bar, or other such instrument, in order to break up the mass or break a passage through.

Much care and attention are required to burn pyrites well. It is no uncommonsthing to find, on examining the waste heap of a manufacturer, that a great quantity has been removed little more than half burned.

It will be observed by these statements of Professor Muspratt, that the plan of construction of these furnaces employed in England for burning pyrites is quadrangular, the sides sloping from topto bottom, and the back and front being vertical; and also that the operation is very imperfect in d-esulphurizing the mineral at all times, while they areliable to interruption from fusion or slugging.

I have been for many years engaged in the manufacture of sulphuric acid in England, with furnaces similar in construction to those described by Professor Muspratt, which are in use there to this'day, and in my experience thesame difliculties have always attended their'working. The residuum or waste is always so highly charged with sulphur remaining in it as to be very noxious when withdrawn from the kilns, requiring the workmen to cover their nostrils with wet cloths to protect them fromthe elfcts of the sulphurous gases; and analysis constantly shows over six per centoof sulphur remaining. The mineral often slugs or fuses into a solid mass when the crow-bar fails to break it up, and the only remedy then is to break out the front of the kiln and remove it bodily, which often brings away the fire brick lining with'it. This happens at least once a week, and frequently twice a week, with each set of kilns.

The operation of removing the moltcninass is very laborious and disagreeable, and the repairs of the kilns expensive. It is also difiicult to get men to do this work. These difiiculties 'in the working of the pyrites burning kilns described arise from a faulty plan of construction, both as to form and proportion, which has been corrcctedin my improved kilns. They are too large, and carry so heavy a burden of mineral, that the heat becomes excessive and renders them liable to slag it, while the bearing of the mass of mineral is so unequal at the sides and corners that it crushes down without check from the top to the bottom, rendering the withdrawal of the burnt part of the material difficult, and quite impossible without an admixture of unburnt pyrites.

Myimproved kiln or furnace is builtround or oval, instead of quadrangular, and tapers regularly from top to bottom, except on the front side, which has a flat, vertical face for the doors,'as hereinafter described. This difference in the plan of construction, between my improved furnace and thequadrangular furnace in use, 'is very-important practically. "The curved taper sides bind, nnd canse the mineral to bear equally at all points,

the pressure tending to the centre, on the principle of an arch, and the mineral supports itself, instead of crushing down, as in the quadrangular furnace, so that it settles gradually as the sulphur burns out; and when the residuum is withdrawn all'above stands undisturbed until the mass is broken down to fill the space of that portion taken away at the bottom. In the quadrangular furnace the heat is not equally distributed throughout all parts, the centre being at a much. higher temperature than the corners, where, consequently, the mineral does not become thoroughly desulphurized unless the fire is raised higli enough to produce fusion in the centre of the mass, which is'the constant tendency of the attempt to burn the mineral thoroughly in the corners. In my improved curved-sided furnace the heat is equally distributed at the centre and sides, and the mineral is all burnt alike withouLthe necessity of raising the tires high enough to fuse the mineral, and consequently it is all thoroughly desulphu-rized in its passage down through the furnace. This result of the operationof my improved furnace has been demonstrated conclusively by the working of a trial set erected at the Richmond Chemical Workson Staten Island, where six kilns were run night and day, without interruption, for more than three months, and were only put out of blast recently for reasons aside from their operation. The burnt pyrites dis charged from these furnaces were so completely desulphurized that no odor was perceptible when they were withdrawn,and-when cold a critical examination failed to detect any unburnt mineral; indeed the sulphur in the residuum is hardly'appreciable upon chemical analysis.

Another important advantage resulting from my improved plan of construction is, being able to charge with large lumps of mineral, instead of breaking it up into small pieces, as heretofore required, thus saving labor and avoiding fin'edust, which is difficult to burn in a kiln.

The dimensions, as well as the proportions, of a-kiln for burning pyritcs successfully arevery important. If made too large in capacity the body of ore is likely to produce too powerful a combustion and fuse themass, and if too small it is difficult to maintain combustion at all. I have avoided these extremes.

The kilns may be built singly or in blocks of any desired number, in pairs placed back-whack; but for the manufacture of sulphuric acid'I prefer a block of six kilns, which will be herein described. For making sulphuric acid, arched crowns and fines, leading the sulphurous vapors to condensing-chambers, are necessary; but. for: desulphurizing metallic pyritous ores the kilns may be built with open tops, like lime-kilns, to discharge into the open air; but a stack, with flues leading to it, is always preferabl to get rid of the gas.

A represents a block of six kilns, B B, arranged in pairs, with fronts on opposite sides. 0 is a stack connected with a condensing-chamber; E, a main flue, and D D branch flues leading from the kilns into it. The

main fine E runs across the block A, and is provided with doors a a at the ends, for the introduction ofpots d dcontaining nitre and sulphuric acid for making sulphuric acid. A flue or open passage, K, runs through the bottom of the block, between the kilns, to equalize the temperature. The block of.kilns is built of brick, about eleven feet square and eight feet six inches high, and is strongly bound at the corners with heavy angle-iron, and with rods running across the sides at top, middle, and bottom. The kilns are made in theform of inverted truncated cones, tapering from the. top to the bottom of the block, in the proportion of about two and a half feet diameter at the top of. the kiln and one foot at the bottom. The front side of the kilns is faced or flattened vertically for receiving doors. Heavy cast-iron door-plates F F are fitted in the front. They are about two feet wide and six feet three inches high. Four flanged door-openings b b are made in the plates, the flanges cast on them andprojecting eight inches into the brick-work, with their back open ends flush with the face of'the kiln. The furnaces or kilns are made without grete-bars. The bottomis level with the lower side of the lowest dooropeuing. On the iron platesFF are grooved projections c c for holding the sliding-doors G G, which set in pairs over each of the openings 6 meeting centrally when closed. Small holes are made in the upper doors for observing the fires. The holes may be covered with mica or luted with clay, as are the crevices of the doors when the furnace is in operation.

The ma n'agement is very simple-and easy. The fire is started with coke, or other suitable kindling stud, and after the kiln has become highly heated the pyrites are introduced at the top of the kiln, by light and gradual charges, until the combustion is regular and well established. The draught is regulated by opening the lower doors more or less, as required; and when the blue flames of the sulphur die out at the top of the charge the burnt mineral is withdrawnfrom thebottom. This is done without disturbing the mass of the urineral above, which is held in check by its equal, arch-like bearing towards the centre from the sides; and after the-withdrawal of the desulphurized mineral the doors next above are opened, and a sufficient quantity of the mineral is broken down with a crow-bar, to fill the empty space below, as required. A charge of fresh pyritcs is added occasionally, and the operation is carried'on with closed'and luted doors, except those tit the bottom,

which sup 1 .the'necessary draught. Tlius my improved'pyrites-burning furnaces may be kept continuously in operation, without the aid of fuel, with great economy and efiiciency, either for the purpose of utilizing the sulphurous vapors or extracting the metals, especially gold and silver, from the thoroughly desulphm-ized mineral.

Having thus described my invention, I claim as new, and desire to secure by Letters Patent- Constructing a furnace for burning pyrites or .sulphurets of iron, copper, zinc, or other metals, without the aid of fuel, in the form of en inverted truncated cone, without grate-bars, and provided with doors on the front side, ranged one above another from top to bottom, substantially as and for the purposes herein described.

JOHN HUGHES.

Witnesses:

WM. F. McNAMAnA, ALEX. F. Ronnnrs.

Images