was kept constant during the tests samples of liquid were taken at different times during the test for analysis the solids at the end of the tests were filtered washed dried and split for chemical analysis table 1 shows the final leaching results for each test these results show that saprolite ore is effectively leached with sulfuric acid at temperatures close to the boiling point at atmospheric pressure without the need of any ore pre treatment or additional reagents during leaching the data also show that at lower acid concentrations the kinetics of iron dissolution lag behind those of nickel and magnesium dissolution resulting in a high nickel extraction and low iron extraction this is an important criterion since iron poses a problem in the downstream recovery of nickel by means known to those skilled in the art a process in which high nickel and low iron dissolution from saprolite ore can thus be devised by leaching the ore with acid concentrations below about 50 g l the nickel extraction as a function of time is illustrated in fig3 which shows that the rate of nickel extraction is a strong function of the sulfuric acid concentration this example illustrates the atmospheric leaching of saprolite ore with a fixed amount sulfuric acid solution at 90 u00b0 c saprolite ore was pulped at 15 solids in deionized water and agitated in a well sealed kettle with sulfuric acid at 90 u00b0 c for 3 hours the initial sulfuric concentration varied from 106 to 114 g l in the 4 tests.