1887.] on the Work of the Imperial Institute. 106 



structive purposes, being unavailable for steel-making by any metliod 

 which could compete with the Bessemer and Siemens processes. 

 Great has been the apprehension among the owners of those ores, 

 that the demand for iron which they can furnish could not revive, but 

 the scientific metallurgist has successfully grappled, from more than 

 one direction, with the great problem of restoring their commercial 

 importance. 



Modifications of the mode of working the rival of the Bessemer 

 process, namely, the open-hearth (Siemens-Martin) process, have 

 given successful results in the production of serviceable rails con- 

 taining higher proportions of phosphorus than had before been 

 admissible, and a simple alteration of the method of carrying out 

 the Bessemer process has, within the last few years, led to really 

 triumphant results, with the employment of those ores which, before, 

 could only be dealt with by the searching operation of the old 

 puddling furnace. By utilising the basic character of lime during 

 the treatment of the melted pig iron, yielded by phosphoric ores, 

 with air in the Bessemer converter, the phosphorus is fixed at the 

 moment of its elimination by oxidation from the metal, and the objec- 

 tionable impurity is held bound in the slag, while a steel is obtained 

 rivalling in freedom from phosjDhorus the product furnished by the 

 pure varieties of English and foreign ore which alone could previously 

 be successfully dealt with by the Bessemer process. This modified 

 treatment of iron for the production of steel, called the hasic treatment^ 

 was soon applied also to the open-hearth (the Siemens and Siemens- 

 Martin) processes of steel-making ; thus a new era was established in 

 steel manufacture by the quick processes, there being now but very few 

 restrictions to their a^Dplication to iron produced from all varieties of 

 ores. Indeed, the treatment is actually being applied profitably to the 

 recovery of iron from the rich slag forming the refuse-product of the 

 puddling furnace in the production of malleable iron, which, containing 

 as it did the phosphorus eliminated from the pig iron by the laborious 

 purifying treatment, had been condemned to limited usefulness as 

 a material for road-making, while now it ranks in market value with 

 some ores of iron. Yet another most interesting and valuable result 

 has been achieved by this simple application of scientific knowledge. 

 The slag or refuse-product of the basic treatment of iron contains, in 

 the form of phosphates of lime and magnesia, the whole of the phos- 

 phorus which it is the main function of that treatment to separate 

 from the metal ; it was soon found that the phosphoric acid which 

 had been produced by the elimination of the pernicious element in 

 the conversion of bad iron into good steel, existed in this refuse 

 slag in a condition as readily susceptible of assimilation by plants as 

 it is in the valuable artificial manure known as superphosphate; 

 the slag, simply ground up, constitutes therefore a manure which 

 is already of recognised value and commands a ready sale at very 

 profitable prices. 



The organisation of this latest advance in the development of 



