The Solubility Of Silicon Dioxide Rule Performance Of AP For Rice Straw

In China, grass fiber raw material was one of main raw materials for pulping. But alkali and lignm from spent liquor were difficult to be recycled because silicon content was very high in rice straw, which caused resource wasted and environment polluted. Silicomolybdate Blue Spectrophotometery(SBS) was used to measure silicon consistence, which disclosing rules of silicon dissolution. To solve the problem of circumstance, kinetics reaction and reaction for silicon dissolution during rice straw alkali-cooking were researched.Firstly, SBS was used to determine silicon content of spent liquor and pulp, which had succeed in measuring silicon content in steel. Silicon in rice straw pulp and spent liquor can be measured by silicomolybdate blue spectrophotometeric method at wavelength 813 run. Silicomolybdate Blue Spectrophotometery was more nicety than avoirdupois method.The influence of pH value of reaction medium on solubility of silicon dioxide was marked, and pH 10.3 was an obvious inflexion .Because pH value over 10.3 solubility of silicon dioxide increased quickly.With alkali charge and cooking time augmenting, dissolution of organic and solubility of silicon increased in Na₂CO₃, NaHCO₃ cooking or NaOH cooking. The process of solubility of silicon dioxide can be divided into stages, such as celerity solubility stage, adsorb stage, redissolved stage. pH value of spent liquor decreased along with increase of cooking time.On the condition that: alkali consistence was 1M NaOH, liquid ratio was 1:20. There were two silica removal stages: main silica removal stage when the temperature increased from 15℃ to 70℃ during 40 min, which was also the bulk stage of delignification. During this stage solubility silicon of rate was 99%, and delignification of rate was 47.9%. The second stage form 90℃ to 155℃ that solubility silicon of rate was about 1%.It was concluded by kinetics reaction that activation energy of solubility of silicon dioxide was 42226.8J/mol. And activation energy of delignification reaction was more 7286J/mol than it. Solubility of silicon dioxide is earlier soluble than delignification in AP for rice straw. Solubility of silicon rate is more 90% that cooking time is 20min, cooking temperature is 70℃, this purpose is grade manage solubility of silicon dioxide.