W. Mallet on the Separation of Lithia and Ma 



139 



r 



\ 



\ 





\ 



or, fn exper. (1.) lOO'SO p. c. of tlie LiCl and 99*53 p. c. of the 

 MgO were obtained, and in exper. (2.) 100*84: p. c. of LiO, SO 3 

 and 99*03 p. c. of MgO, 



Again 



mixtures were made of (1.) '8644 grm. of LiCl and 



•1640 grm. of MgO (dissolved in HCl) 



(2,) 2-5426 



grm. of 



LiCl and -8396 grm. of MgO— (3.) '6906 grm. of LiO, SO3 

 and -3536 grm. of MgO (dissolved in SO 3)— (4.) about -7000 grm. 

 of LiCl and '6741 grm. of MgO. Each of these solutions was 

 boiled with milk of lime in excess, and filtered, the residue on 

 the filter redissolved in muriatic acid, lime precipitated from the 

 solutions of now separated magnesia and lithia by oxalate of 

 ammonia, and, after filtration, the lithia determined as anhydrous 

 sulphate and the magnesia as ammoniacal phosphates, with the 



following results : 



Found. 



LiCl 

 LiCl 



(1-) 



(2.) 

 (8.) 



(4.) LiCl 



Present. 



•8644 

 2-5426 2-5499 



LiO, SO 3 



•6906 



•7000 



•6920 



MgO 

 MgO 



^IgO 



MirO 



Present 



•1640 

 •8396 

 •3536 



•6741 



Found. 



•1628 

 •8363 

 •8499 

 •6703 



or the following per-centage proportions of the substance pres- 



ent were found : 



(1.) 



(2.) 

 (3.) 



(4.) 



LiCl 

 LiCl 



100^29 

 Li,0 SO 3 100-20 

 LiCl 



100-56 p. c. and MgO 99-27 p. c. 





u 



u 



u 





99^61 



98-95 

 99^43 



U 



u 



a 



We thus find a constant small excess of lithia and small loss 

 of magnesia. . Owing to the facility with which both sulphate of 

 baryta and oxalate of lime pass through the pores of even a 

 yery close filter, traces of these salts \vere found in the sulphate 

 of iithia weighed, partly accounting for the slight excess in. 

 which the latter substance appears ; but the errors for both bases 

 determined are confined within so narrow limits^ and the re- 

 sults compare so fairly Avith those obtained in other commonly 

 employed processes of quantitative analysis, that these two 

 methods for the separation of magnesia from lithia, may be 

 looked upon as good and reliable. In cases where we have to 

 deal with but small quantities of the bases, baryta water will be 

 found the more convenient reagent, while on a larger scale, when 

 we wish to keep the volume of liquid within moderate limits, 

 and when the relative cost of baryta and lime requires consider- 

 ation, the latter, used in the state of thin creamy mixture with 

 water, is rather to be recommended. 



