Abstract

The three important methods for the fixation of atmospheric nitrogen are, In historical sequence, the arc, cyanamide and the synthetic ammonia pro- cesses, though other methods such as the nitride and the cyanide processes have been put forward from time to time. In discussing the relative advant- ages of these methods we must have certain criteria of judgment, e. g., the capital outlay, running expenses, availability of raw products in the vicinity of the factory and the suitability of the products to the local market. The arc process requires a much larger outlay and consumes a much greater amount of electricity per unit of nitrogen fixed than the cyanamide and synthetic ammonia methods. Hence it has been adopted only in countries where electric power is abundant and very cheap, e. g., in Norway, Sweden, Canada, etc. Even these countries have now given up the method in favour of the synthetic ammonia process, which is much cheaper.

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