80 Transactions Tennessee Academy of Science. 



been thoroughly estabHshed by a recent agricultural research. A 

 fine phosphate limestone would add to the soil at a reasonable cost 

 both carbonate and phosphate of lime. I am not aware that the 

 material* has thus been utilized as yet. Various processes have 

 been devised which may utilize low grade phosphates which are 

 dependent upon the heating of the raw material in contact with 

 other cheap materials. For this purpose one of the most promis- 

 ing appears to use an iron compound, if I am rightly informed — 

 the ordinary liminite ores of this section. One process doing this 

 uses the ordinary rotary cement kiln. Various compounds of the 

 alkali methods have been tried, but it would appear that their cost 

 is against their economic utilization. The use of salt is, of course, 

 not practical on account of the introduction of chlorine. I have 

 heard rumors also of the mere heating of the material to a high 

 temperature being effective, but have been unable to get anything 

 definite along these lines. It would appear that the presence of 

 silica in the impure phosphate might lead to favorable results if 

 it were possible to form lime silicate instead of lime phosphate 

 through the intervention of a material acting as a katalyst. At any 

 rate, many men are working on the problem, and it is not supposed 

 that it cannot be solved. 



In the meantime, as far as my knowledge of the field goes, it is 

 not advisable to place any restrictions around the industry in or- 

 der to prevent exportation from the state of the high grade ma- 

 terial. Under present conditions there is enough of this alone to 

 last for many years. It would be more to the point to encourage 

 research into methods for the utilization of the low-grade de- 

 posits. 



