the sulfate ion to iron ion is between 1 6 and 1 45 and is preferably about 1 5 the reactants water sulfuric acid air oxygen and ferrous sulfate are thoroughly mixed in the ferric sulfate reactor using mixing jets air is passed into the reactor at a rate of 10 500 cfm using an aeration jet or any other device to effectively add air to the system at atmospheric pressures the air stream in addition to mixing or agitating the reactor contents provides the oxygen for the oxidation of the ferrous to ferric the reaction preferably is carried out at a temperature of between 120 u00b0 f and 300 u00b0 f and preferably at about 180 u00b0 f the reactants preferably have a residence time of 18 hours in the reactor with a feed of 44000 lbs day of ferrous chloride solution containing 17 fe by weight it is reasonable to expect a production rate of about 21 tons of ferric sulfate a day by sizing the equipment correctly the iron in the finished product stream is about 12 ferric iron the whole process should take about 18 hours the above reaction can be accomplished in a batch or continuous reaction with reference to the figure 44 000 lbs day of pickling liquor is introduced into an hcl generator 10 by a feed line 12 at a rate of about 30 56 lbs min on a continuous basis prior to starting the feed the hcl generator 10 is filled.