THE PHILIPPINE ^i^nian In'st^^ 



Journal of Science'? apr 7-19.7 <.i 



A. Chemical and Geological Sciences \.%f ^^s^ 



AND THE Industries ^^''flal Mu^^J-^ 



Vol. XI JULY, 1916 No. 4 



THE STRIPPING AND THE ANALYSIS OF GALVANIZED IRON ' 



By George W. Heise and Amando Clemente 



{From the Laboratory of General, Inorganic, and Physical Chemistry, 



Bureau of Science, Manila, P. I.) 



INTRODUCTION 



The extensive use of galvanized-iron products has led to the 

 development of a voluminous bibliography on the manufacture, 

 corrosion, testing, and stripping of zinc-coated iron. With the 

 present increase in the price of zinc, from 10.10 pesos ^ per 

 hundred pounds (about 45.36 kilograms) in July, 1914, to 37.50 

 pesos in January, 1916, the recovery of that metal becomes 

 a problem of more and more importance.' It is the purpose 

 of this paper to give a brief outline of various methods of analy- 

 sis and stripping heretofore proposed, together with the results 

 obtained in this laboratory. 



When a shipment of galvanized-iron roofing is to be analyzed, 

 so large a number of determinations is often necessary that 

 a laboratory test should be extremely simple and rapid, as well 

 as accurate. Although there are many factors, such as the 

 purity and porosity of the zinc, influencing the durability 

 of galvanized iron, in general, the most important factor is 

 the thickness of the coating.* The amount of iron and other 

 impurities in the zinc is generally small, and no serious error is 

 involved even if they are included as part of the weight of 



' Received for publication March 25, 1916. 



' One peso Philippine currency equals 50 cents United States currency. 



'Juretzka, F., Metall u. Erz (1915), 3, 63 and 94. 



* Walker, W. H., Proc. Am. Soc. Test. Materials (1909), 9, 431. 



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