| Summary: | The pickle liquid waste from the pickling process causes environmental pollution. This problem could be solved by reacting the waste with ash extract and air to produce K2SO4 that can be used as fertilizer and ferric hydroxide, which can be used as pigments.
The reaction between the pickle liquid waste, ash extract, and air was carried out in a stirred tank reactor, batch wise as well as continuousaly. The batch process was started with pouring the ash extract into the reactor and heated to the desired temperature. The, heated waste was added, and at the same time air was bubbled from the bottom of the reactor. Samples were taken at 15 minutes intervals, until 120 minutes of reaction time. The continuous process was started with filling the reactor with ash extract and heated to the desired temperature. Then a certain quantity of heated waste and air with certain flow rate were introduce separately into the reactor, and stirred rigorously. During the process, the temperature was kept constant using a water bath. After steady state was reached, samples were taken to determine the ferrous and ferric contens of the filtrate and the suspension.
Based on effects of temperature and agitation, the rate of reaction and the mass transfer were simultaneously controlled the rate of the process. Within the range of variables studied, the reaction rate constant and the mass transfer constant were effected by temperature exponentially and iogarithmicaly by the agitation, respectively.
Processing of 500 cm3 suspension produced 2.62 g of red pigments of Fe203 and 18.24 g of K2SO4 crystal.
Keywords : pickle liquid waste - ash extract - stirred tank reactor
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