Used steel drums are usually cleaned in hot, approximately 10% NaOH. Addition of about 0.3% "SEQLENE" solids will cause light rust to dissolve. Heavier rust can be removed by increasing "SEQLENE" concentration up to 3%. Some platers add about 0.5% "SEQLENE" 540 or 1% "SEQLENE" Es-50 or 270 (equivalent to 1-0.25% "SEQLENE" Es-40; 1-0.5% "SEQLENE" 190) to their regular alkali cleaner thus enabling it to remove light rust and other oxides. "P.R.Alkaline Descaling" prior to plating is a special case of alkaline derusting in which it is necessary to remove oxides more obdurate than freshly hydrated ferric oxide including Fe3O4 in weld marks, etc. The following is typical of successful commercial operations: Solution Strength per Gallon: 1 lb. NaOH 1/2 lb. NaCN 1-1/2 lbs. "SEQLENE" 190 (or 1/2 lb. "SEQLENE" 540 or 1 lb. "SEQLENE" Es-50) 0.1 lb. EDTA (or HEDTA OR DTPANa5) Heavy periodic reverse current, cooling to about 125'F (to reduce hydrolysis of NaCN to ammonia), 3 minutes immersion. The EDTA der
地址：山东省烟台市开发区南昌大街48号
