STUDY ON OXIDATION REACTION OF THE COOKING BLACK LIQUOR OF RICE STRAW WITH AMMONIUM SULFITE METHOD

摘要

In this experiment, the black liquor of ammonium sulfite of rice straw was oxidation by using oxygen. The effects of oxygen pressure, reaction time and temperature and concentration of black liquor on the contents of nitrogen carboxyl group and value of pH and C/o-N were discussed. It could be inferred from the results that the properly improved oxygen pressure and reaction temperature and prolonged reaction time could contribute to the oxidation. But the concentration of black liquor should not be too high. After oxidation under the optimum condition, of the modified product, 34.82% of total nitrogen was organic nitrogen. The content of carboxyl group was 9.18mmol/g and the value of pH is 5.2. C/o-N had decreased to 5.03,which absolutely conformed to the standard of slow-released nitrogen fertilizer.