OCR Text |
Show Copper Rsflnlnrj by Electricity. Tho cost of coppor tiffining by electricity elec-tricity has been roduced greatly in rccont yoars in tho Amorlcan ro-flnorles ro-flnorles by tho Introduction of mo-chanical mo-chanical dovlcos for casting tho anodo slabs of crudo copper and tor charg-and charg-and discharging tho vats. According to an artlclo by Mr. John I). C. Kershaw Ker-shaw In Cnsslor's Mnga-'no, the expenditure ex-penditure on hand labor has thus boon greatly reduced, and tho time during which vats aro laid on for recharging and cloanlng has beon curtailed. Tho current density used has also boon greatly' Incrcnsod by Jho uso of improved im-proved methods of circulating tho electiolyto, and by the addition ot n very small pcrccntago ot hydrochloric acid to tho. copper sulphate solution. |