Prof. V. Ya. Mostovich.

Copper-Smelting Plants in the Yenisei Province

(Report on the summer assignment of 1914.)

Taking advantage of the assignment granted to me by the Council of the Tomsk Technological Institute, in the summer of 1914 I visited several plants in the Yenisei Province. The copper-smelting plants of Yuliya and Ulén were of the greatest interest to me. Since, as far as I know, there is no description of these taiga plants in the literature, wishing to fill this gap, I decided to publish the present sketch, supposing that it will facilitate for those interested an acquaintance with the indicated plants.

I. The Yuliya Plant.

The Yuliya mine and plant, situated in immediate proximity to one another, belong to the joint-stock company “Siberian Copper” and are located in the Minusinsk district of the Yenisei Province, 270 versts from Achinsk station of the Siberian Railway and 70 versts from Bateny station of the Achinsk–Minusinsk road.

Mining of ores and smelting of copper in the Yenisei Province was carried on already in very remote times by its original inhabitants—the Chud. Old Chud dumps of ores and copper slags are encountered in many districts of the Yenisei Province and serve even at the present time as the most reliable indication of the occurrence of copper ores in these districts. Thanks to the same Chud dumps, the ore deposits at the Yuliya mine were discovered.

In its character the deposit at the Yuliya mine belongs to the contact-metamorphic type¹.

The ore district is composed of Devonian limestones. Subsequently the limestones were broken through by granitic rocks which poured out onto the surface, which caused metamorphism of the limestones; they partly turned into spar and marble and contain much silicic acid, granite, feldspar, hornblende, and epidote. In these limestones there also occur copper pyrite, iron pyrite, bornite, either in the form of disseminations or of more or less considerable accumulations—nests. The ore-bearing bed is the richer in copper-containing minerals the nearer it is to the contact of the limestones with the granitic rocks. In the upper horizons oxidized ores predominate; in the lower ones—sulphide ores.

Regular exploitation of the mine began in 1904. The plant was put into operation in 1907, and at it ore from the Yuliya mine is smelted almost exclusively.

The following numerical data characterize the scale of the enterprise since the start-up of the plant.

According to the estimate for 1914 it was proposed to mine 1,500,000 poods of ore and to smelt 31,737 poods of pure copper.

Chemical composition of the average ore sample:

Cu 1.8%; Fe 4.81%; CaO 20.42%; MgO 0.5%;
S 4.1%; SiO₂ 34.92%; Al₂O₃ 16.12%; Ag + Au.

As is seen from the analysis given, the ores belong to the category of self-smelting ores, which do not require the addition of fluxes during smelting.

Smelting.

Smelting is carried out in the following manner. The ores in raw form are smelted in a shaft water-jacket furnace to matte. The latter is crushed and roasted on grates. The roasted matte is smelted in a stone shaft furnace to black copper, which is refined in a reverberatory furnace and cast into anode plates for further refining by electrolysis. In the following scheme the entire course of the processes and the circulation of products at the Yuliya works are presented.

Smelting scheme.

Ores in raw form are smelted in a water-jacket shaft furnace, —

→ Matte.
Cu—41%.

→ Waste slag.
Cu 0.17–0.20%.

Matte is crushed in a Blake crusher to 5–10 m/m, roasted on grates to 3–4% S and smelted in a Ural shaft furnace.

→ Black copper.
Cu 93%
↓
Refined in a spleisofen.
↙︎ Anode copper.
↓
Cu 99.6%.
↘︎ Refining slags.
↓
to smelting for black copper.

→ Bottoms.
Cu 55–56%
↓
Crushed, roasted on grates and smelted to black copper.

→ Return slags.
Cu 1–3%.
↓
Poor slags go to ore smelting.
Rich slags to smelting for black copper.

→ Speiss.
Fe Cu
↓
To smelting for black copper.

Smelting on matte. Since the ores are self-fluxing, only ores with small quantities of circulating slags are sent to the charge for ore smelting.

Composition of the charge: 93% ore + 7% poor slags from smelting to black copper.

The fuel used is mixed hardwood and pine charcoal. For one basket of coal of 30 poods, 160 poods of ore or 175 poods of charge are smelted, which gives, per 1 pood of coal, 5.3 poods of ore or 6 poods of charge; consequently, the consumption of coal is 16.7% of the weight of the charge or 19% of the weight of the ore.

The charcoal is delivered from charcoal pits located in the forests surrounding the plant, and costs the plant 5.5 rubles per basket of 30 poods. The yield of charcoal from firewood is 50%. The charcoal is of low quality: it contains much underburnt and overburnt material, and therefore crumbles during transport.

The smelting of ores is carried out in a water-jacket furnace, the drawing of which is given on Plate I. The furnace has a rectangular cross-section at the tuyeres, \(36'' \times 120''\), and is equipped with 18 tuyeres of 4″ diameter; on each long side there are 9 tuyeres. The blast is delivered to the furnace through an air duct 20″ in diameter from a Roots blower at a pressure of \(1''\) Hg column. The blower is driven by a vertical 80-horsepower steam engine.

The height of the furnace from the hearth to the charging floor is \(16'3''\); from the tuyeres to the charging floor, \(13'6''\); the total height of the furnace from the plant floor to the charging floor is 19′. The charging opening has a clear size of \(5' \times 10'\).

On each long side of the furnace three iron jackets are installed, and on the short side one jacket. The height of a jacket is \(8'6''\). Beneath the jackets the shaft is lined to \(7'9''\) with fireclay brick. For cooling the jackets, partly water from a well situated \(1 \tfrac{1}{2}\) versts from the plant is used, and partly return water from the jackets, collected in a trough at the plant itself. The temperature of the outgoing water is \(60^\circ\text{C}\); about 6 cubic meters of water per hour are consumed for cooling the furnace.

The charging floor of the furnace is open. Above it a vaulted iron hood with charging windows along the long sides of the furnace is erected; the length of a window is \(11'16''\), the height \(1'6''\). The iron hood is connected to a central iron flue pipe 3′ in diameter and \(20'6''\) high for removal of the charging-floor gases. There are no dust-collecting devices. The quantity of dust is considerable, but it consists chiefly of coal fines carried out of the furnaces by the blast.

Ore and coal are brought to the charging floor over a wooden inclined bridge in iron cars, and charging into the furnace is done by hand. In an eight-hour shift, from 35 to 40 charges of 70 poods each are let down, and in a day the furnace smelts on average 7,500 poods of ore or 8,000 poods of charge. The shift consists of: above, 3 ore carriers, 3 coal carriers, 3 chargers; below, 1 smelter, 1 assistant, 6 slag haulers.

In all there are 17 men per shift, and 51 men per day.

The products of smelting, matte and slag, flow out of the furnace continuously along an iron trough lined with brick and clay (see the description of the Uspensky plant) into a front movable forehearth. The latter is composed of four side and one bottom cast-iron plates 20–25 mm thick. The walls of the front forehearth are not lined inside, but are coated with a mixture of clay and coal fines (1:1). When the forehearth is filled, slag forms, replacing the lining. The forehearth has a clear size of \(140\ \text{cm} \times 100\ \text{cm} \times 50\ \text{cm}\). The trough serves for 10 days, the front forehearth for 3 days. The discharge of slag from the front forehearth is continuous into slag cars. On the four-wheeled platform of the car are fixed racks, on which are suspended ...

in the shafts there are two conical cast-iron boilers with a capacity of 25 poods each. Matte is discharged from the forehearth periodically into cast-iron molds; on the average up to two discharges per day are made per shift, and 275–300 poods of matte are obtained per day, which amounts to from 3.4 to 3.75% of the weight of the charge being smelted, or 3.7–4% of the weight of the ore.

With a copper content in the ore of 1.8%, in the matte of 40%, and in the slag of 0.17%, the degree of concentration of the copper is equal to

\[ \frac{40}{1.8-0.17}=25. \]

Average analysis of the products of ore smelting:

matte: 41% Cu, 35% Fe, and 24% S.
slag: Cu—0.17–0.20%, FeO—11.8%,
SiO₂—41.4%, Al₂O₃—12.3%,
CaO—28.4%, MgO—3.5%.

On the basis of these data one may approximately calculate the degree of desulfurization of the process.

if it is assumed that the weight of the dump slag differs only slightly from the total weight of the charge, i.e., amounts to 8000 poods, and that the sulfur content in the slag is 0.3%, then \(0.003 \times 8000 = 24\) poods of sulfur pass into the slag. Consequently, during smelting \(300 - (72 + 24) = 204\) poods of sulfur are burned out, and the total desulfurization amounts to 66%. Such a low degree of desulfurization is explained by the use in smelting of a considerable quantity of charcoal, amounting to 19% of the weight of the ore and producing an insufficiently strong oxidizing atmosphere in the furnace. But with 1.8% Cu and 4% sulfur in the ore, this desulfurization ensures the production of a 40% matte and quite waste slags. More intensive desulfurization would have as its consequences: a decrease in the yield of matte, an increase in the copper content in it, and, consequently, an increase in the copper content in the slag. With such poor ores as the ores in Yulia, the gravest consequence would, of course, be an increase in the copper content in the slags. Even under the present smelting conditions the loss of copper in dump slags amounts to 12% of the copper content in the ore, as is seen from the following calculation.

Charged into the shaft:

There are obtained 300 poods of matte with 41% Cu, or 123 poods Cu; the loss in slags, if the very small loss in dust is neglected, amounts to \(140 - 123 = 17\) poods of copper per day, or 12.2%.

An increase of the copper content in the slags by only 0.05% would increase its loss through slagging by as much as 3% (8000 poods of slag with 0.05% copper give 4 poods of copper, which of 140 poods of the latter amounts to 3%). The high degree of acidity of the slags (1.4–1.5), their comparatively low specific gravity, owing to the small FeO content and the predominance of CaO and Al₂O₃, and the hot running of the furnace—all this accounts for the cleanliness of the slags and the normal copper loss in them. These conditions are realized only when a sufficient quantity of fuel is used in smelting, which prevents excessive desulfurization of the process with all the harmful consequences arising from it. Therefore it would seem that, under the special smelting conditions at Yulia, a record in reducing the consumption of...

fuel in ore smelting would appear to be an aspiration rather irrational than expedient in an economic respect.

The smelting of 100 poods of ore costs at Yulia 6 rubles 33 kopecks; the share of fuel, with its consumption at 19%, amounts to 3 rubles 50 kopecks, or 55% of the total cost of smelting. From 100 poods of ore approximately 100 poods of slag are obtained, and, if by reducing the fuel consumption in ore smelting by 2% we obtained in the slags only 0.05% more copper, this would mean an increase in the loss of copper by 53 kopecks per 100 poods of ore, or by 42 rubles 40 kopecks per day on one furnace.

Roasting of roshtein. The matte is crushed in Blake’s crusher to grains of 10 mm, moistened with water, and enriched on horizontal grates with upper blast. The length of the grate is 3 meters, the width 1.5 meters, and the depth 25 cm. The grate is covered with a removable iron hood equipped with an air-supply pipe. During roasting the gaps between the grate and the hood are sealed with clay. To ignite the operation, the matte is covered with a thin layer of burning charcoal. With the blast started, combustion begins from above and gradually spreads through the entire mass of matte. In one operation 60 poods of roshtein are roasted, and one firing lasts 8 hours. Roasting of the matte is repeated three times, and after each firing the roasted matte is crushed and moistened with water. Since after each firing the calorific capacity of the matte is greatly reduced owing to oxidation of the sulphides, before the second and third firings 2–3% of charcoal fines, or so-called siftings, are added to the matte. The blast pressure during roasting is about 0.5″ of mercury column. After the third firing the matte contains about 3% sulphur.

Smelting for black copper. This smelting is carried out periodically, as roasted roshtein accumulates. The smelting is conducted in a stone shaft furnace of rectangular section, depicted on Plate II. The furnace top is charged through a sumpf. The section of the furnace at the tuyere zone is 70″ × 32″. The height of the furnace from the tuyeres to the grate is 6′3″; the height from the bosh to the tuyeres is 21″; consequently, the whole height of the shaft from the bosh to the grate is 8′. The distance from the bosh to the tymp, or the height of the tymp opening, is 18″. In the back wall of the furnace there are seven tuyeres; the diameter of a tuyere is 2½″. The blast is supplied from a common air main and enters the furnace under a pressure of ¾″ of mercury column. Slag flows out of the sumpf continuously. After 18 hours of smelting, the blast is stopped; black copper and matte are tapped from the sumpf into the front forehearth, and the black copper is removed in rosettes. During the blowing, i.e., over 18 hours, the furnace smelts 1200 poods of charge, with a consumption of 1 box (30 poods) of charcoal per 120–130 poods of charge, which amounts to from 4 to 4.3 poods of charge per pood of charcoal.

The charge for matte smelting consists of roasted roshtein, matte, return slags, and siliceous fluxes, such as furnace breakouts and old slags. The following table illustrates the operation of the furnace over a period of 18 days.

Charged into the furnace:

Obtained: black copper 2246 poods, lohstein 1737 poods.
Composition of the smelting products: black copper—92.8% Cu and 6.83% Fe; lohstein 55–58% Cu.

From 100 poods of ore charged into the shaft furnace, 18.2 poods of black copper and 14.1 poods of lohstein are obtained.

For an eight-hour shift, six workers are assigned to the furnace: 1 smelter, 2 assistants, and 3 slag tappers.

Refining of black copper. For refining there are two reverberatory furnaces of the Bogoslovsk type with simple fireboxes for wood (see drawing of the furnace on Plate II). The floor area of the furnace is \(8\frac12' \times 9'\); the area of the grate is \(2'8'' \times 8'6''\). The furnace operates on \(6/4\)-arshin wood. In one furnace, 360–390 poods of black copper are refined per day, and three charges of 120–130 poods each are processed, with a consumption of 2.5 cubic sazhen of wood per day. One complete operation lasts eight hours and consists of the following processes:

For one operation ten birch poles, two meters long and 3 vershoks in diameter, are consumed. The refined copper is cast into anodes weighing \(3\frac14\) poods each. From 100 poods of black copper, 89.4 poods of anode copper and 13.8 poods of refining slags are obtained. For an eight-hour shift, one smelter and three assistants are assigned to the furnace. The copper is cast by means of ladles holding 30 pounds of copper. The anode copper contains 99.6% Cu and about 60–70 parts of gold per 100 poods.

Machine department. In the machine department there are the following installations. One vertical 80-horsepower steam engine, driving a Root blower, which supplies blast for the shaft furnaces. Two horizontal steam engines of 25 horsepower each. These engines serve a dynamo for lighting, pumps for pumping water in the reverberatory furnace caissons, a Schiele blower, supplying blast for roasting lohstein, and machine tools located in the machine department. At Blake’s crusher a separate 12-horsepower steam engine is installed.

All mechanisms are served by two steam water-tube boilers of the Stirling Boiler system, with heating surfaces of 1304 and 805 square feet, installed in the boiler house and fired with wood. For casting in the mechanical workshops there is a cupola furnace.

According to the data for 1913, the cost of ore, fuel, and individual operations at the plant was as follows: the cost of 1 pood of ore was 7.44 kopecks; the cost of 1 box \(= \frac14\) cubic sazhen \(= 30\) poods of charcoal at the plant was 5 rubles 50 kopecks; the cost of 1 cubic sazhen of wood was 12 rubles; smelting one pood of ore into lohstein was 6.33 kopecks; smelting one pood of lohstein into black copper was 21 kopecks; refining one pood of black copper was 27 kopecks.

Per one pood of copper the following are required:

1. refining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25.19 rub.
2. general plant expenses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20.86 rub.
3. overhead expenses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 rub. 92 kop.

Total cost of one pud of copper . . . 9 rub. 93 kop.

At the end of 1914, at the Yulia plant, coke began to be used in ore smelting, gradually replacing charcoal with it. When 60% of the latter is replaced by coke, smelting proceeds successfully, and this promises to reduce the cost of ore smelting.

II. Ulen Copper-Smelting Plant of the Industrial and Commercial Partnership Vladimir Alekseev.

The plant is located in Minusinsk uyezd, Yenisei Province, 300 versts from Achinsk station of the Siberian Railway, and 140 versts west of the town of Minusinsk.

At the plant, ore is smelted from the Glafirinsky mine, situated four versts away, and from the Antonininsky mine, situated two versts from the plant.

Exploration work at the mines began in 1906. In November 1911, ore smelting was begun in shaft furnaces of the Ural type and, from April 1914, in a water-jacket shaft furnace.

The state of production since 1911 is characterized by the following data:

In 1914–1915 it was planned to smelt 30,000 puds of copper. At present intensive exploration is being conducted, and the reserve of ore already explored amounts to four million puds.

According to their mineralogical composition, the ores smelted at the plant may be divided into two categories:

1. Ores of the Antonininsky mine. The ores are strongly pyritous and are characterized by a predominance of copper pyrites and pyrite, disseminated as impregnations in granite rock. The average copper content in these ores is 2–2½%.

2. Ores of the Glafirinsky mine. These ores consist of a mixture of pyritous and oxidized ores. In the oxidized ores from the upper horizons, malachite and azurite predominate in a soft clayey and ocherous rock containing a considerable quantity of brown iron ore. These ores are richer than those of the Antonininsky mine, and the average copper content in them is 4½–5%.

The pyritous ores of the Glafirinsky mine occur in the form of impregnations or seams in sienites.

The chemical composition of their average sample over two and a half years:

1. Glafirinsky ores:

2. Antoninian ores:

Cu — 2.73%
SiO₂ — 30.26%
Fe — 18.23%
Al₂O₃ — 5.36%

CaO — 19.45%
MgO — 1.47%
MnO — 1.08%
S — 2.23%

H₂O, O, CO₂ — 19.19%
Au 1 zol. 51 dol.
Ag 8 " 43 "
} per 100 poods.

According to the results of smelting, the average copper content in the smelted ores proved to be as follows:

for the first year of operation . . . . . . . . . . . . . . . . 4.88%
" second " " . . . . . . . . . . . . . . . . . 3.15%
" third " " . . . . . . . . . . . . . . . . . 3.44%

The ores are brought to the plant on horses and dumped into ditches of trapezoidal cross-section, dug in the soil and lined with boards.

The width of a ditch at the top is 11 arshins, at the bottom 5 arshins, depth 3 arshins, the slope of the side walls 45°; the length of a ditch is from 18 to 90 arshins. The ditches are arranged in five parallel rows. A transverse ditch adjoins the last row at a right angle. In all there are 11 ditches; of these, seven are occupied by ore and their total capacity is 375,000 poods of ore; four ditches with a capacity of 1,200 cubic sazhen are assigned to charcoal.

Beneath the ditches, on the same level as the charging platform of the shaft furnaces, lies the yard, and on it rail tracks with turntables are laid for bringing ore and fuel to the charging platform. The separate kinds of ores are dumped into the corresponding ditches, and the charge is composed at the charging platform. At present, in order to ensure more regular feeding of the furnaces, it has been decided, as an experiment, to use one ditch for charging ore. A ready charge will be brought to the charging platform, which also promises an improvement in the results of smelting.

Smelting for matte. The Ulensk ores belong to the category of self-smelting ores, and therefore only a small admixture of limestone goes into the ore-smelting charge, besides ore. The most advantageous composition of the charge was worked out at the plant by prolonged experiments. The charge is made up with such calculation as to obtain matte with 35–40% Cu and, in [[unclear: obscured phrase]], ores in the raw state, return slags from matte smelting to black copper, and limestone. In 100 parts by weight of the charge: raw ores 75 parts by weight, return products 12 parts by weight, limestone 13 parts by weight.

Ores, return products, and limestone are brought to the charging platform in iron cars of 1 cubic arshin capacity, and fuel, charcoal, in wooden boxes of 1/40 cubic sazhen capacity, mounted on a four-wheeled platform. The charging of the furnace is carried out by hand, in horizontal layers.

Ore smelting is conducted in one water-jacketed and one stone shaft furnace of the Ural type. The fuel used is mixed deciduous and pine charcoal, burned from deadwood in kilns located in the forests surrounding the plant. The yield of charcoal in kiln burning is 50%, and a cubic sazhen of charcoal, weighing on the average 115–120 poods, costs the plant 16 rubles 50 kopecks. Coal from the ditches is loaded into boxes by means of American forks with seven slightly bent tines. Fines and screenings go, as refuse, for filling heaps when roasting matte, for filling the forehearth, etc.

The water-jacketed shaft furnace of rectangular cross-section has the following dimensions: tuyere belt 36″ × 66″, charging opening in the clear 79″ × 79″. The number of tuyeres is eight, four on each long side; tuyere diameter 3½″. The height of the furnace from the plant floor to the charging platform is 11′.

The blast pressure is 1″ of Hg column. The water-jacket consists of six caissons; the thickness of the inner wall of the caisson is 3/8″, of the outer one—5/16″; the width of the water space is 5″. For feeding the caissons, water from a water pipe is used, coming from the furnace with a temperature of about 70°C. The daily water consumption for the whole furnace is 7000 buckets.

The productivity of shaft furnaces gradually increased as the workers gained experience in handling them. During the first year, the stone shaft furnace smelted no more than 1300 poods of charge per day; by the third year—up to 2250 poods; the daily productivity of the water-jacket furnace is 3200–3500 poods of charge. For one cubic sazhen of 120 poods of coal, 450–500 poods of charge are smelted, and the fuel consumption averages 25% of the weight of the charge. Slag and matte flow out continuously along a short iron launder into the forehearth. For discharging matte and slag from water-jacket furnaces, a launder with water cooling, or the so-called trap-spout, is usually used. At the Leninsk plant and at the Yuli trap-spout has been replaced by a launder made of boiler iron; the length of the launder is 1½ arshins, width 10 vershoks, depth 6 vershoks. Inside, the launder is lined with refractory brick and coated with refractory clay. The thickness of the lining at the bottom of the launder is ¾ brick, and at the side walls—½ brick. In the front part of the launder a clay sill is arranged. During operation the launder is covered with the same iron launder, lined only with clay. The preparation of such a launder requires only a few hours of work, and the duration of its service is 10–12 days. Replacing the trap-spout with a simple launder of the construction described above is a great simplification in the operation of the furnace. Distinguished by great simplicity of construction and assembly, comparative ease and low cost, the simple launder eliminates, moreover, the danger of explosions occurring when cracks form in the walls of the trap-spout or when the latter are eaten through. When a trap-spout is used, repair and replacement of the forehearth are connected with the necessity of stopping [[unclear: obscured word]] and increasing the water feed to the launder. With the simple launder such stoppages are not required; it is sufficient merely to raise the clay sill in the front part of the launder.

Slag and matte flow continuously into the front movable rectangular forehearth, 36″ × 40″ × 20″, of the same construction as at the Yuli plant.

The slag from the forehearth flows continuously into slag cars holding about 10 poods, and is transported partly to the dump, partly to the foundry yard, where bricks (10″ × 10″) are cast from it, used for laying floors, foundations, and other plant structures. Immediately after casting, the slag bricks are covered with a layer of refuse consisting of a mixture of dry clay with coal fines (1 : 1); in this poorly heat-conducting medium the bricks cool very slowly over 24 hours, which contributes to their strength and stability. The chemical composition of the waste slags is:

1) Slag from water-jackets:

2) Slag from stone shaft furnaces:

The tapping of matte from the front hearth is carried out twice per shift, or six times per day, into cast-iron molds lying on their own floor.

Composition of the matte: Cu—41%, Fe—30.7%, and S—24.7%.

About 220 poods of matte are obtained per day. Thus, the yield of matte is 7% of the weight of the charge, or 9% of the weight of the ore. With an average copper content in the ore of 3½% and in the waste slag of 0.3%, the concentration ratio of the matte is 13.

On the basis of analyses of ores, matte, and slags, the desulfurization in water-jacket smelting may be approximately calculated.

Per day the furnace smelts 3100 poods of charge, including 2550 poods of ore. The average sulfur content in the ore mixture, consisting of 30% Giafiran and 70% Antonian ores, is 3.64%; with this ratio of the individual ore grades, the copper content in the ore mixture is 3½%. Further, we may assume that the amount of slag will be approximately equal to the weight of the charge, and that its sulfur content will be 0.3%.

In this case, 0.0364×2550=92.8 poods of sulfur are charged in the charge per day; 220 poods of matte are obtained, containing 0.25×220=55 poods of sulfur, and 3400 poods of slags, containing 0.003×3400=10.2 poods of sulfur. Consequently, 92.8−(55+10.2)=27.6 poods of sulfur burn out, and the total desulfurization amounts to 30%.

Such weak desulfurization is explained by the large fuel consumption, 25% of the weight of the charge, which is required for the normal progress of the smelting.

The furnace top is open; above it is laid a vaulted hood of red brick with side openings corresponding to the dimensions of the furnace top and having a height of 2′. The hood is provided with an iron pipe 35′ high, through which the hood gases escape into the atmosphere. There are no dust-collecting devices at the plant.

For charcoal with a low ignition temperature (360–380°C), the water jacket of the Ulensk plant has insufficient height, which is why top burn-off is often observed; when the latter appears, the furnace top is cooled by pouring water on it. For the same reason, one should not apply a strong blast and thereby increase furnace productivity. On coke, as a denser and stronger fuel having, moreover, a higher ignition temperature (700°C), the furnace of the Ulensk water jacket could easily smelt from 7000 to 8000 poods of the same charge per day. But under the conditions of the Ulensk plant, the cheapest and most accessible fuel is still charcoal.

For an eight-hour shift at the furnace, 12 workers are employed; of these, on the furnace top: chargers 2, ore carriers 2, charcoal carriers 2; at the hearth: smelter 1, assistant 1, slag removers 4.

The smelting of ores to matte is also carried out in a chamber shaft furnace, the so-called Ural furnace.

The furnace is built of ordinary brick, has a trapezoidal cross-section, and the gases are led from it through a flue. The wide wall has inside the shaft a width of 9′, the front wall 6′; the distance between these walls is 2′10″. Eight tuyeres of 2½″ diameter are placed in the rear wide wall of the furnace. Blast pressure ¾–1″ of mercury. The height of the furnace from the crucible bottom to the tuyeres is 2′2″, from the crucible bottom to the furnace top—10′5″; from the plant floor to the furnace top—14′. With the cheap and simple construction, furnace campaigns without repair, but with daily cleaning, last 12–13 months. Per day the furnace smelts 2200 poods of the same charge as the water-jacket furnace.

For one kub. or 120 puds of charcoal, 350 puds of charge are smelted, or per 1 pud of coal, 2.9 of charge; in the water-jacket furnace, per 1 pud of coal, 4 puds of charge are smelted, or by 38% more.

Owing to the large consumption of fuel and, consequently, the stronger reducing atmosphere in the furnace, the desulfurization of the process is undoubtedly less than in the water-jacket furnace. In addition, during smelting the reduction of a considerable quantity of iron is inevitable. A large part of the iron is separated in the form of blooms on the hearth of the furnace, while some of the iron dissolves in the matte. As a result of all this, the matte from ore smelting in the Ural furnace is usually 5–7% poorer than the matte from the water-jacket furnace with the same charge.

The slag flows out of the sump continuously; the matte is tapped twice per shift. In twenty-four hours 120–130 puds of roasted matte are obtained, which amounts to 8% of the weight of the ore smelted. In an eight-hour shift at the Ural furnace there are employed seven persons: 1 smelter, 2 charge-men, 2 ore and coal haulers, 2 slag haulers.

Processing of roasted matte. This processing consists in the preliminary roasting of the roasted matte and its smelting for black copper in a shaft furnace. The matte is roasted partly in heaps, partly on grates or in pans; in the near future it is intended to roast only on grates.

Roasting in heaps. The fire under the heaps is made from slab bark. On a bed of firewood, brushwood, and woody refuse, matte is thrown in pieces from 3″ to 5″; the weight of matte in one heap is 2000 puds. The sulfur content in the roasted charge is brought to 3–4%, which requires roasting in eight fires. One fire lasts on average seven days. At the same time the ripened heap is smelted.

Roasting on grates. Part of the matte is crushed in a Blake crusher and then on rolls to a grain size of 1/4″. The crushed matte is moistened with water, mixed with fines from ore, charge, and dust, and roasted on cast-iron grates of the Ural type; there are four such grates, each measuring 5′ × 5′. With a charge of 40 puds of matte, one fire lasts six hours. Roasting is conducted in three fires; consequently, the duration of the complete roasting of one charge of 40 puds is 18 hours.

The sulfur content after the third fire is likewise brought to 3–4%. The grates are set at a slight angle on one common channel connected to a flue. During the operation of the grate they are tightly covered with casings of sheet iron. Each casing is provided with a pipe with a valve, through which upper air is supplied under a pressure of 3/4″ of mercury, supplied by a Schiele special fan.

Smelting for black copper. The charge for this smelting consists of roasted matte and dühnstein in the amount of 90% and 10% fluxes. The latter are reverts and refinery slags, furnace sweepings, and partly quartz ore, as materials rich in silicic acid. The fuel is charcoal, one pud of which smelts on average four puds of charge. Smelting is carried out in the above-described Ural shaft furnace of trapezoidal section. From 100 puds of charged charge there are obtained 15–16 puds of black copper with 93% copper, 7–8 puds of dühnstein with 55–60% copper, and 78–76 puds of return slags containing from 1 to 3% copper. In twenty-four hours the furnace smelts 2400 puds of charge, and in an eight-hour shift 25 men are assigned to the furnace.

The black copper is subjected to refining; the dühnstein is roasted in two fires on grates and goes together with the roasted matte to smelting for black copper. Return slags containing less than 1% copper give

to the mine for ore smelting, while the richer slags go to smelting for black copper.

Refining of black copper. Refining is carried out by the usual shaft-furnace method of the Bogoslovsk type, with a simple hearth for the matte. One shaft furnace yields on average about 100 poods of black copper per day, and, if the furnaces are operated in 3 to 4 shifts, i.e. refined, 300–400 poods of black copper.

The product of the smelting is: 1. refined copper with 99.7% Cu, containing up to \(1 \tfrac{1}{2}\) zolotniks of gold and silver per pood of copper; 2. refining slags. The latter are returned to the smelting of matte for black copper.

Thus, both the processes and the circulation of products at the Ulensk plant are the same as at the Yuliya plant.

For the operation of the plant and the mines, the machine department of the plant has the following installations. One Lenz fan of 19 horsepower, actuating a Root blower; the latter, at 320 revolutions per minute, delivers 7,000 cubic feet of air per minute, at a pressure of \(3/4\) pound, or 39 mm of mercury.

One Lenz locomotive of 78 horsepower. This locomotive serves a dynamo of 19.5 horsepower for lighting the plant and the factory buildings in the nearby settlement, and one generator of 45 horsepower. The generator serves the mines and the mechanical workshop at the plant.

Drills, bellows, and valves for crushing matte are driven by Naphtha internal-combustion engines installed in the machine department of the plant.

The Ulensk enterprise owes its origin and organization to the initiative and energy of the mining engineer M. F. Debarro, who now heads all the enterprises on the Ulen.

With special gratitude, the author of this article, who has devoted [[unclear: several words obscured]] to this matter, recalls the factory and mining engineer [[unclear: name/phrase obscured]]. At the plant, in view of the prolonged illness of the mining engineer, the work was carried out by the [[unclear: title/name]] of the mine.

The author considers it his duty to express deep gratitude to the manager of the Yuliya mines, mining engineer M. B. Feigin, and to the manager of the Ulensk enterprises, mining engineer M. F. Debarro, for their kind reception and for the information supplied during the trip.

Roin, March 1905.

Shaft Furnace.

Visible drawing annotations and dimensions:

• \(35''\)
• \(5'9''\)
• \(3'4''\)
• \(8'6''\)
• \(2'0''\)
• \(10''\)
• \(2'7''\)
• \(1'4''\)
• \(1'9''\)
• \(5'2''\)
• \(8{,}8\)
• \(10{,}2\)
• \(4'7''\)
• \(4'0''\)
• \(50^\circ\)
• \(6'3''\)

Scale: 1:50.

sazhens \(2\) \(0\) \(1\) \(2\) \(3\) \(4\) \(5\) \(6\) \(7\) \(8\) \(9\) \(10\) feet.

Experimental furnace.

Visible dimension markings in the upper drawing: 10", 14", 10"; 10"; 28"; 18"; 36"; 26"; 60".

Visible dimension markings in the lower drawing: 17'6"; 35"; 28"; 9'0"; 5'0"; 3'0"; 11'0"; 32"; 2'6"; 8'7"; [[unclear: small dimension at lower right]].

BATE1

![Technical drawing of an industrial apparatus with dimensions; visible labels: “Rb-” on the left and “-ZhA” on the right.]

NO.
Scale: 1:25 n. s.

1. “The Yuliya Mine,” V. N. Tomilin. Transactions of the Mining Institute of Empress Catherine II, vol. V, issue 1, p. 49 (1914). ↩