Page images

perature is far too high for the follow- a state of nitrous vapor-peroxide of ing process in the subsequent apparatus nitrogen—and the presence of the water for the production of the nitric acid, the is essential to convert this vapor into gas is submitted to a thorough cooling. nitric acid. At the same time, however, In the first place it passes through a tubu- as this chemical action is taking place lar radiator wherein its temperature is re- inferior oxides of nitrogen are also produced to approximately 200 degrees Cen- duced during the progress of the process.

[graphic][merged small]

tigrade. The vapor that is produced dur- The absorption towers, which are recting this operation is in itself utilized at angular in shape and of 1412.56 cubic a later point for the concentration of the feet capacity each, are ranged on either solutions of nitrate of lime. From this side of the central passage through the cooler the gas is carried through ad- building in two parallel lines. There are ditional similar apparatus wherein the four main towers built of masonry and temperature is still further reduced until two subsidiary towers the function of it approximates fifty degrees Centi- which will be described later. In the four grade, which is the most suitable tem- principal towers are placed quantities of perature for the following operations. broken pieces of quartz about the size These elaborate cooling systems are of the fist, and circulating around the inplaced at the top of two large towers terior in opposite directions are the supwhere the oxidation of the nitrogen is plies of gas and water. As the water by carried out. These towers are con- continuously playing upon the broken structed of iron and are lined with a quartz keeps the latter in a constantly material which is impervious to the cor- moistened condition, the moisture is rosive action of nitric acid. After re- seized by the gas and becomes charged maining a short while in these towers with formed nitric acid ; the other nitrous the nitric oxide from the electric furnace products present in the nitric oxide and becomes transformed into peroxide, the lesser oxides are re-oxidized in the which is dispatched through conduits to tower by coming into contact with the what are called absorption towers, in air and in turn also yield nitric acid. which the nitric oxide becomes absorbed This process of absorption is continued in the water and forms nitric acid. At until the nitric acid solution produced in this stage the oxide of nitrogen in com- the towers has reached in course of rebination with the oxygen of the air is in peated contacts between the gas and the water a concentration of fifty per cent the aid of nitric acid into nitrate (i. e. 50 kilograms of nitric acid mon- of lime and peroxide of nitrogen ohydrate in 100 litres of liquid), when it gases, and then re-introduced into the is collected in open vats and temporarily principal absorbing system already menstored until required for the manufacture tioned where the process of absorption of nitrate of lime.

is repeated in the manner described. Although the greater proportion of the By the time the gas has issued from nitrous products contained in the gas are the fifth tower it contains but a very arrested during the passage of the lat- small percentage of nitric oxide that has ter through these absorption towers it is escaped, but even the greater part of this of great import from an economic point remaining percentage is reclaimed by of view that only the minimum of the nit- passing the gas through the second and ric-oxide mingled with the gas that smaller, auxiliary absorbing plant which passes from the electric furnace should contains live lime. After passing through elude absorption by the water and thus this vessel the gas is permitted to escape escape into the outer air. It is for this into the outer atmosphere. So complete purpose that the two subsidiary towers and thorough, however, is the system already mentioned are employed. The adopted for absorbing the nitric oxide in first of these two tanks is built of wood this series of tanks that the quantity of and is of the same dimensions as the nitrogen gas oxidized in the electric furprincipal absorbing tanks, only instead of naces which successfully escapes iş inbeing charged with pieces of quartz, a significant. Many comparative analyses more energetic absorbing medium is and observations have been carried out utilized. This absorbent, milk of lime, by independent and distinguished scienis deposited upon bricks with which the tists to ascertain the quantity of nitric tank is lined and the nitrous gas is oxide that resists seizure and these have seized by this medium, giving an extrac- revealed the fact that ninety-five per cent tion of nitrite and nitrate of lime. This of the oxide of nitrogen produced in the mixture is subsequently dissolved by electric furnace is arrested and converted




[ocr errors]

into pure nitric acid, leaving only a waste of five per cent. This is a truly noteworthy achievement in industrial economics.

For the manufacture of the nitrate of lime, calcium is the reagent employed, the attack of the nitric acid upon this substance producing a concentration of the nitrate. This operation is carried out in a series of open vats made of granite containing pieces of calcium varying in size from five to eight inches in diameter. Carbonate of lime is used in limited quantities in this process for the purpose of completely neutralizing the acid and

ABSORBING PLANT. to give an extraction of neutral nitrate Here the nitric oxide is extracted from the gas. of lime. This latter action takes place in four super-imposed vats or tanks, the also possible to produce at these works neutralizing action being carried out in a basic nitrate of lime by adding to the uppermost receptacle upon the new the dissolved calcium a certain procalcium. The liquid is displaced auto- portion of live lime. After cooling matically from one tank to the other and the product is broken up and sifted. This when the operation is completed there re basic nitrate contains about ten per cent sults a dissolved neutral nitrate of lime of nitrogen. It must be understood that which is drawn off and carried to an although the foregoing description reevaporating vat.

lates to the production of nitrate of lime, The concentration of this liquid is ef- the nitrates of soda and potash can be fected partly by the aid of the vapor produced with equal facility. It is the which results during the cooling of the low cost of the lime as compared with the gas immediately after its escape from the soda and potash which has resulted in the electric furnace, as already described, application at Notodden of the process and partly direct. The temperature of to the conversion of the nitric acid into the solution is raised until it attains 145 calcareous nitrates. degrees Centigrade, at which point a With the present plant in operation at liquid containing a concentration of sev- Notodden it is possible to produce with enty-five to eighty per cent of calcium each of the electric furnaces 250 tons of nitrate possessing from 13.2 to 13.5 per nitric acid, which is equivalent to 325 cent of nitrogen is produced. The prod- tons of calcium nitrate or 337 tons of uct is then discharged into metal casks nitrate of soda, per year. Consequently and is then solidified by cooling. It is the total output of the plant per annum

is equivalent to approximately 1,000 tons of Chilian saltpeter. Owing to the complete success that has attended the operations so far it has been decided to carry out considerable extensions to these works, the scheme comprising an installation of thirty furnaces which will enable an annual production of 20,000 or 25,000 tons of calcium nitrate to be


necessary energy a large generating station is to be erected upon the river near by, the ural world and to which Sir William available waterfall to be thus harnessed Crookes pertinently referred owing to being capable of furnishing some 30,000 the insufficient supplies of nitrates from horse-power. The process is also to be natural sources for fertilizing purposes developed in Sweden and Germany, is possibly to be averted. The two Northough in regard to the latter country wegian scientists who have evolved this some difficulty may be encountered in latest process for producing artificial connection with the obtaining of suffi- nitrates from the atmosphere have succient cheap water-power since the topo- ceeded in overcoming the difficulties graphical features of Germany are de- which proved insurmountable to previous ficient in this respect, whereas in Nor- investigators in the same realm of apway and Switzerland, there abound nu- plied science, and once the system has merous waterfalls of varying horse emphasized its commercial practicability power and which can be easily and from a financial point of view, extensions cheaply harnessed.


Here nitrates are being successfully produced from the atmosphere. Total

energy 2,500 horse-power.

in all parts of the world for supplementIt would appear therefore that the ing the nitrate supplies obtainable from grave danger confronting the agricult- South America are inevitable.

Mountain Haze

The purple shadow of an angel's wing

Is flung across the range and softly creeps

Adown the mountain-side; the rocky steeps
Are blurred with veils of amethyst that fling.
Their filmy folds 'round barren spots that cling

To jagged slopes; the yawning canyon keeps

Fond tryst with Dusk, the windless forest sleeps,
With naught save one fair, long line lingering.

So, when the angel-shadow falls on me,
And from Life's landscape I am blotted out,

Ne'er to return to my accustomed place,
In Memory's haze let my shortcomings be
Concealed, forgotten, but may no one doubt
That I the line of beauty sought to trace.


[merged small][graphic]

Last Days of the Fur-Seal

By P. T. McGrath

HE long fight over the of the former make the valuable sealskin famous Bering Sea seal sacques of the women of fashion, while fishery is again about to those of the latter are converted into her be reopened diplomatic- dainty gloves, footwear and pocketbooks. ally, and this fact once The fur-seal herds on rocky Alaskan

more directs popular at- islets and brings forth its young on these tention to an industry which has been flinty foreshores, then swims for thouthe subject of more literary productions sands of miles through the surrounding —in prose and poetry, fact and fiction- ocean, pursuing its favorite food. The than any other marine pursuit known to hair-seal herds on the naked ice-floes man in modern times. Kipling has im- off Labrador, drops its, offspring into a mortalized it in his “Rhyme of the Three snowy bed there, and when the southSealers," Jack London in the “Sea Wolf," speeding floes are melted by the Gulf and a host of lesser penmen have stream, takes to the water and vanishes, made it the theme of their writings; and its movements for ten months of the year an international arbitration at Paris in being unknown. The fur-seal's skin is 1892 provided such a number of publica- today worth $125, requiring four to make tions on its more technical features as a lady's coat, and the annual kill is about would form a library in themselves. 40,000. The hair-seal's hide fetches but

These fur-seals of the north Pacific $25.00, is turned to a variety of purposes, differ in many essentials from the hair- and the annual catch is about 300,000. seals of the north Atlantic. The pelts It is estimated that the number of seals

« PreviousContinue »