| 摘要 |
Activated bentonite based clarifying earth and ammonium-nitrate fertilizer are prepared. Activated bentonite based clarifying earth and ammonium-nitrate fertilizer are prepared as follows: Acid activated bentonite clarifying earth is obtained by treating bentonite with a solution of nitric acid. A microelements containing NH4NO3 fertilizer is obtained when residual waste nitric acid is neutralized with ammonia. In order to prevent or control reabsorption and hydrolysis of multi-valent ions (Al, Fe) resulting from the acid-activation process, active bentonite is washed with a sequence of varying strength nitric acid solutions, prior to rinsing with water. Pretreatment with nitric acid at room temp. results in saving energy as lower specific quantities of acid are needed later during the high temp. acid activation step. Recirculation of acid solutions in processing, rinsing and digestion stages and the use of washing solutions in a concentration gradient sequence, result in savings both of acid and water. |
