96 On Zinc Desilcerization, 



DKSILVERIZATION. No. 1.* No. 2. 



87,394 lbs. 





3,497 " 





83,797 lbs. 



62,895 lbs 



6,31)5.6 oz. 



6,165.9 oz 



1,760 lbs. 



1,260 lbs 



9,525 " 



6,862 " 



7,810 " 



3 500 " 



1,000 " 



700 " 



808 " 





67,104 " 



53,420 " 



Quantity of work lead charged in the kettle 



Taken off ; " Schlicker " (cuprous oxide) - 



Pure work lead, . . . . 



Silver contained, - - - - 



Quantity of zinc added, 



Weight of skimmings after liquation, 



" Abstrick" from dezincation of poor lead. 



Oxides and metallic lead from the market kettle, 



Lead from liquation of zinc-crust, 



Market lead, ----- 



At Cheltenham, the liquated skimmings, still soft, are thrown 

 on iron gratings from 1 to 1\ inches apart, and pushed through 

 in order to reduce it to pieces of small size, which can be more 

 conveniently introduced into the retort. In most of the works, 

 it is thrown upon an iron plate in front of the kettle, and in 

 order to break it up, is rapidly moved about with a rake, and if 

 necessary cut up with a shovel, so that the pieces are about the 

 size of a hickory nut. 



3. Refi)iing the Desilverized Lead. — The lead in kettle No. 1, 

 which contains I per cent, of zinc, no matter what the heat is, 

 or how much zinc is added, must be refined, to separate the 

 zinc and get it ready for the market. This operation is one of 

 refining ; but in the West it is known under the name of " cal- 

 cination. " This is done in a furnace with a cast or tank iron 

 bottom, like the softening-furnace, holding about 20 tons. At 

 Mansfield Valley, the bottom is made of tank-iron. Fig. 5 

 represents the furnace used ab the G-ermania works. The 

 one used at Cheltenham is essentially the same ; it is a little 

 larger, but the dimensions vary only a few inches. The fire- 

 place is 2 feet 3 inches wide and 4 feet 5 inches long. The 

 bridge is eight inches below the roof on the fire-place, and eleven 

 inches on the hearth side. It is 2 feet 10 inches wide, 3 feet 6 

 inches long, and 2 feet above the hearth. The hearth is 13 

 feet 4 inches long, and 7 feet 3 inches wide in the middle, and 

 3 feet 6 inches wide, both at the fire-bridge and the fine. It is 



* No. 1 is lead taken directly from the shiift furnace, which has not been softened. No. 2 

 is softened lead. 



