August, 1908.J 



145 



Scientific Agriculture. 



which the manufacturer of nitrogen com- 

 pounds has to face is found in the cost of 

 the new product. Although this can be 

 marketed at a price below the cost of 

 Chili saltpetre and similai fertilizers, the 

 margin of profit is as yet not sufficiently- 

 great to attract the notice of those who 

 are looking for an investment to yield an 

 extraordinary return. In this, as in all 

 new enterprises, those who will benefit 

 most are the manufacturers first in the 

 field, for in spite of the present conser- 

 vative profits to be derived, the methods 

 of manufacture of the new products are 

 already being cheapened and improved. 

 This, taken into conjunction with the 

 undoubted facts that the natural supply 

 of nitrogen compounds is diminishing, 

 and the demands of agriculture are in- 

 creasing to an unprecedented extent, 

 renders it certain that the factories 

 which now take control of the supply of 

 artificial nitrogen fertilizers will, in a 

 very short time, be placed in a most 

 advantageous position. 



Calcium Cy ax amide. 



The manufacture of the new fertilizer, 

 calcium cyanamide, is conducted accord- 

 ing to the Frank and Caro method, an 

 electro-metallurgical process, the Europe 

 rights of which are held by the Societa 

 Generate de la Cianamide, of Rome, Italy. 

 Already many subsidiary companies are 

 in operation, chiefly in Italy, France, 

 Norway and Switzerland, which are con- 

 ducted on a profit-sharing basis in 'con- 

 junction with the general Company. The 

 manufacture of calcium cyanamide is 

 performed on the principal that calcium 

 carbide absorbs nitrogen when heated 

 to a sufficiently high temperature. The 

 calcium carbide is first produced in the 

 usual manner by heating lime and coke 

 to a temperature of 2,500 degrees centi- 

 grade in electric furnaces of the resis- 

 tance type. The carbide is then heated 

 in retorts, and at 1,100 degrees (C), 

 atmospheric nitrogen is introduced and 

 absorbed, the new compound being 

 known as calcium cyanamide. 



The first plant erected for the manu- 

 facture of calcium cyanamide was at 

 Piano d'Orta, Italy, in 1905. ' In this 

 factory were installed six furnaces, each 

 with five retorts for the absorption of 

 nitrogen by the carbide. Each retort 

 works off three charges daily, consisting 

 of 1000 kilograms (2,200 lbs.). The absorp- 

 tion of nitrogen by the carbide increases 

 the weight materially, and from each 

 charge 125 kilograms (275 lbs.) of calcium 

 cyanamide is obtained. The plant has, 

 therefore, an annual capacity for the 

 conversion of 3,000 tons of carbide into 

 3,750 tons of cyanamide. This factory is 

 operated by water power, supplied by an 

 independent Company. The generating 

 19 



station, where a head of 90 feet, supply- 

 ing 8,400 h.p. is available, is more than 

 six miles from the cyanamide plant, to 

 which the power is transmitted at 6,000 

 volts. The factory has proved so success- 

 ful, that already an extension to an 

 annual 10,000 tons capacity is in progress, 

 and other similar plants are projected 

 throughout the country. 



In France, the Societe Franchise des 

 Produits Azotes is already in operation, 

 and another in Savoy has an annual out- 

 put of 3,750 tons. In Germany and 

 England the Frank and Caro process is 

 also being actively operated, and in the 

 United States the America Cyanamide 

 Company of Alabama will have an 

 annual capacity of 20,000 tons. 



The method is already being improved, 

 and the chemist, Polzeniusz, has dis- 

 covered an important modification in 

 the manufacture of cyanamide. This 

 is brought about by the addition of 

 Fuor-spar to the carbide which facili- 

 tates the absorption of nitrogen at the 

 comparatively low temperature of 400 

 degrees (C), and, moreover, produces a 

 product which does not so readily be- 

 come moist. The market price of cyana- 

 mide is at present regulated by the 

 price of the two competing artificial 

 manures, ammonium sulphate and ni- 

 trate of soda. Its actual cost of produc- 

 tion has been found in Germany to 

 average about $40 per ton, which has 

 been marked at a little over $50. This 

 has been achieved in cases where cheap 

 water power was available, but as the 

 process improves, the rival fertilizers 

 will, without doubt, be eventually driven 

 from the market by this and similar new 

 products. 



Calcium Nitrate. 



Another noteworthy new artificial 

 fertilizer, calcium nitrate, is manufac- 

 tured by the Birkeland and Eyde pro- 

 cess, at Notodden, in Norway. This 

 product is obtained on the principal that 

 at the extreme heat of 3,000 degrees 

 Centrigrade, atmosphoric nitrogen can 

 be made to directly combine with oxy- 

 gen. Although this fact has long been 

 known, the intense temperature required 

 has been against the general adoption 

 of the process, but by the use of the 

 electric arc flame it is now operated on a 

 large scale. The chemical combination 

 of nitrogen and oxygen thus achieved 

 produces nitric acid gas. The compound 

 is afterwards passed through absorption- 

 towers through which water and milk of 

 lime flow. The resulting liquid obtained 

 is then evaporated and solid nitrate 

 of lime (calcium nitrate) is obtained. 



The Notodden plant was established 

 in 1903. It possesses three furnaces, 

 each producing 250 tons of nitric acid 



