Utilization of nitric acid wastes from bleaching earth production

Nitric acid activation of bentonite has been studied with the aim of harmon izing bleaching earth and ammonium nitrate fertilizer production, where the latter is obtained from waste acid via neutralization with ammonia. In thi s paper, a mathematical model is described for composition measurement of t he waste acid formed during the activation of the bentonite. On the basis o f the results obtained from the model, the amount of concentrated nitric ac id necessary for refreshing the recycled acidic solution can easily be esti mated. The amounts of the products formed during ammoniacal neutralization, such as ammonium nitrate, hydroxides of hydrolizable metals, and nitrates of nonhydrolizable metals, as well as the amount of activated bentonite, ca n also;be calculated. It is established that, with an increase in the recyc ling number, the activation process becomes more economical via decreasing energy and material requirements.