CHEMICAL DISSOLUTION OF CROUTES FORMED DURING PRESSURE LEACHING OF NICKEL OXIDES AND SILICATES

摘要

P IN THE LEACHING OF NICKEL OXIDE OIL AND SILICATE BY SULFURIC ACID UNDER HIGH PRESSURE, THERE IS TREND IN THE FORMATION OF CROUTES ON THE WALLS OF AUTOCLAVES. THE CROUTES CONTAIN OXIDES AND SULFATES OF METALS SUCH AS ALUMINUM, IRON, SILICON AND MAGNESIUM. AFTER COMPLETING A LEACHING OPERATION, THE CROUTES ARE CHEMICALLY ELIMINATED BY RINSING THE AUTOCLAVE WITH A SOLUTION OF SULFURIC ACID CONTAINING ABOUT 20 TO 100GL HSO, AT A TEMPERATURE BETWEEN 150 AND 250C AND UNDER A PRESSURE BETWEEN 371KPA AND 3852KPA APPROXIMATELY, FOR A TIME SUFFICIENT TO REALIZE A SUBSTANTIALLY COMPLETE ELIMINATION OF THE CROUTES. / P