PRODUCTION OF POTASH SALTS. 39 



The above analyses would seem to show that, generally 

 speaking, the proportions of potash and phosphate in the various 

 types of ash depend mainly upon the method of production. In 

 the case of both softwoods and hardwoods the analyses show 

 that the ash produced in forest fires has a greater potash and 

 phosphate content than ash produced in mill fires. This is 

 probably explained by the fact that in the forest fires there is a 

 larger proportion of branch wood, twigs and leaves, all of which 

 are relatively richer in potash and phosphates than the ''slab" 

 material which comprises the mill fuel. The ash of bracken is 

 seen to be very much richer in potash than any types of wood 

 ash, and as bracken is often found in association with coniferous 

 plantations the admixture of bracken ash will increase the total 

 yield of potash from such areas. 



Utilisation of Material. 



Analyses show that this material as a potash manure is very 

 similar in nature to kainit, and may be used for similar purposes. 

 In addition, however, the wood ash contains a considerable 

 proportion of phosphate which adds greatly to its manurial 

 value. An experiment on a commercial scale showed that the 

 mechanical condition of the ash is excellent ; this allows of it 

 being used with advantage in compound manures, in which it 

 functions as a "dryer." According to recent experiments 

 conducted at Rothamsted,^ "wood ash readily mixes with super- 

 phosphate without heat, smell or caking." In this connection, 

 taking for granted that the methods of production, collection, 

 storage and marketing prove successful, it is highly probable that 

 this material could compete successfully with kainit, even in 

 normal times, when it would have an average selling price of 

 about 60s. to 70s. per ton. At the present time, however, a better 

 price should be realised.- 



High-Grade Salts. 



The production of certain high-grade potash salts from the 

 crude ash is a matter which does not present much difficulty. 

 The method consists, in the first place, of extracting the potash 

 lye by lixiviation of the ash with warm water, or with quicklime 



* See The Journal of ihe Board of Agrictdttire, vol. xxi., No. 8, p. 697. 

 ''' On the basis of 4s. per unit soluble potash, and is. 3d. per unit 

 hosphate. 



