

On the Occurrence of Gallium in Clay-ironstone. 401 



metal, the gallium lines are decidedly stronger in the spectra of 

 the substances extracted from the metal. 



One kilo, of finely powdered ore was mixed with dilute hydro- 

 chloric acid of double normal strength, measuring about 1250 c.c. 

 Some carbon dioxide was disengaged and an insoluble residue left 

 .which was removed by filtration. The filtrate was then heated when 

 a gelatinous separation of silica occurred. After evaporation to 

 dryness, a further addition of hydrochloric acid yielded a solution 

 which was not highly coloured, and, presumably, did not contain 

 much iron. The silica rendered insoluble was removed by filtration, 

 and to the filtrate ammonium chloride and ammonia were added. 

 The precipitate thus formed was dissolved in hydrochloric acid, 

 reduced with sulphur dioxide, nearly neutralised, and boiled with 

 sodium thiosulphate. The precipitate was dissolved in hydrochloric 

 acid and again precipitated by ammonia. 



This precipitate was examined for gallium. The insoluble residue 

 was also examined, and a comparison of the two spectra showed that 

 a larger quantity of gallium remained in the insoluble residue than 

 was extracted by the acid. It was found that gallium could be 

 .extracted from this by fusion with caustic soda and lixiviation with 

 water, and that the residue, after such treatment, contained no 

 gallium. Operations on this particular ore were suspended until 

 other samples had been examined. , 



The following ores from the collection in the Royal College of 

 Science, Dublin, were examined: 



1. Yorkshire clay ironstone from near Middlesbrough. 



2. Clay ironstone from Grosmont, Whitby, Yorkshire. 



3. Northamptonshire ore (clay ironstone). 



4. Black band ore, Mount Melville mine, St. Andrews. 



One kilo, of each was reduced to fine powder, and 100 grams of 

 Nos. 1, 2, and 3, and 500 grams of No. 4 were extracted with dilute 

 hydrochloric acid as in the previous case. In each sample gallium 

 was found, but the proportion was very small in the Northampton- 

 shire ore, and still more minute in the black band. Without operat- 

 ing on several hundred grams it would have been scarcely possible to 

 detect the gallium in the Mount Melville ore. These ores had not 

 been roasted, and in this they differed from the sample received from 

 the North Eastern Steel Works. The effect of roasting is the same 

 as increasing the proportion of gallium in the ore. 



Estimation of Gallium in the Blast Furnace Metal from Middlesbrough. 

 The sample weighing 575 grams consisted of 155 grams of fine 

 powder and 420 grams of coarse powder. The latter portion was 

 heated with hydrochloric acid until the acid was nearly neutralised, 

 when the liquid was decanted and filtered. 



