264 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



to agriculture, they will be much more important as population 

 increases and the domestic supplies are actually and proportionately 

 less. 



RECOVBBY AND UTILIZATION OF WOOL-SCOURING WASTES. 



Work on the utilization of wool-scouring wastes was continued 

 during the year. The routine analytical work on representative 

 wool samples which was necessary to supplement the fragmentary 

 information available as to the nonfibrous constituents of raw wools 

 from various sources was finished early in the year, completing the 

 data on more than 300 samples of all grades and varieties. 



Work was continued on the economical recovery and utilization 

 of potash from wool wash waters and an experimental wool-washing 

 machine has been built to try out a process for removing the potash 

 from wool prior to the regular scouring operation for removal of 

 grease, whereby the potash is obtained in a solution of such concen- 

 tration that it can be used in preparing mixed fertilizers with little 

 or no further concentration. In collaboration with manufacturers, 

 mixed fertilizers have been prepared on an experimental commercial 

 scale from concentrated wool wash water, acid phosphate, and leather 

 scrap which were found by laboratory examination and analj^sis to 

 be of good grade and which, in pot tests made by the Bureau of 

 Plant Industry, proved to be satisfactory for promoting the growth 

 of wheat. Samples of both domestic and foreign wool-scouring 

 wastes have been analyzed for comparison of their content of potash 

 and other fertilizer materials. Work on the recovery of potash from 

 the water effluent discharged from the centrifuges of a commercial 

 wool plant indicated that, while the remaining grease and most of 

 the organic matter could be removed by treating the warm liquor 

 with sulphuric acid, ferric sulphate, or preferably calcium chloride 

 ^ and filtering, it was not practicable to recover potash from the treated 

 effluent because of the high cost of concentration. 



In cooperation with manufacturers using the solvent scouring 

 process for removing the grease from wool, considerable work has 

 been done on improving the quality of grease obtained from the 

 extracts. It was found that the quality of grease that can be made 

 depends upon the grade of wool that has been extracted. With the 

 improved treatment developed in the laboratory it was possible to 

 obtain an excellent grade of neutral, ashless grease, which was 

 really a good grade of anhydrous lanolin, from solvents used in 

 extracting wools of certain grades. 



Work has also been done on the purification of commercially pro- 

 duced wool greases, and in this connection numerous centrifugal and 

 acid-cracked greases have been examined according to the methods 

 devised in the laboratory. The results obtained indicate that while 

 centrifuged greases may be purified and converted into anhydrous 

 lanolin at a reasonable cost, it is impracticable to attempt any fur- 

 ther purification of acid-cracked greases. 



In cooperation with commercial wool-scouring mills, work has been 

 done on samples of by-products, including scouring liquors from first 

 and second bowls, sediment from scouring bowls, sludge removed 

 from acid-cracking tanks, and filter press cake. A series of experi- 

 ments has been started to determine the difference between raw wool 



