532 



Basic Slag: Second Interim Report. [Sept., 



procedure is likely to be made with the purpose of improving 

 either the output or the quality of slag. We are compelled to 

 recognise that from the steel makers' point of view basic slag is 

 relatively unimportant. On the average rather less than 4 cwt. 

 are obtained for each ton of basic steel produced, and while 

 a ton of steel has been worth from £27 in 1920 to £10 

 in 1921^ the 4 cwt. of slag are worth not more than 2s. to the 

 steel makers (and only about 6s. at makers' works even after 

 the slag grinder had gi-aded, ground and bagged the slag). The 

 steel maker cannot afford to alter his processes in any way that 

 would lengthen them or make them more costly or hazardous. 

 The practical result is that the composition of basic slag is deter- 

 mined by the conditions under which the steel maker is working, 

 and the total amount producible is regulated by the demand for 

 steel; neither of which factors is in any way within the control 

 of the agriculturist or influenced to any appreciable extent by his 

 demands. 



Various possibilities, such as the reintroduction of low grade 

 slags into the blast furnace, the use of ores containing more 

 phosphorous, etc., have been examined. Some of these methods 

 are in partial use, where local conditions favour them, but any 

 wider application is ruled out by the increased consumption of 

 fuel which is usually necessary, and which is frequently accom- 

 panied by decreased output of the blast furnaces and in 

 consequence increased cost of the pig iron. 



5. Eemedies for Shortage. — Having established the facts that 

 the output of slag is less, and likely to remain less, than could 

 adva'ntageously be used by farmers, and that we can neither 

 expect any increase in quantity of slag apart from increased out- 

 put of steel, nor look to the steel makers to improve its quality, 

 v/e are investigating the possibility of increasing the effective- 

 ness of basic slag and the possibility of finding effective sub- 

 stitutes in ground mineral phosphates. 



(a) Effectiveness of Slag. — One of the slags tested in the field 

 in 1921 gave considerably better results than could have been 

 anticipated from its chemical composition. We are going closely 

 into this matter to see if any improvement in effectiveness is 

 possible. 



(h) Suhstitution of Mir-ieral Phosj)hates. — The prehminary 

 survey of last year has shown that the use of ground mineral 

 phosphates would afford a ready means of solving this difficult 

 problem. We have begun a careful inquiry into the fertiliser 

 value of these phosphates. 



