本試驗乃針對目前台灣以稻草爲原料行蘇打法製漿所遭遇回收因難問題，予以進行稻草亞硫酸鈉法製漿及稻草亞硫酸鈉法重覆使用蒸煮黑液製漿，並與蘇打法製漿比較，尋找最佳製漿方法及條件，並探討稻草製漿系統中，SiO2含量之分配及基對漿或廢液之影響。並進行亞硫酸納法製漿廢液回收試驗，以期對問題之解決有所助益，使台灣稻草於製漿之利用率大幅提高。根據實驗結果得知：採用稻草亞硫酸鈉法並重覆使用蒸煮黑液漿，用藥量10%(as Na2O)，高液比(5:1)，較溫和蒸煮，且蒸煮前予稻草預先洗浄，綜合所得之製漿結果，優於蘇打法，且重覆使用蒸煮黑液，可減少廢液回收系統之負荷量及設備之損耗。SiO2在漿中之留存率高於蘇打漿，又重覆使用蒸煮黑液製漿，則SiO2之分配逐次在漿中增加而在廢液中減少。應用Al(OH)3爲藥品回收媒體行廢液回收，回收方法操作簡單、投資低、無汚染顧顧慮、安全性高，在試驗過程中可回收Na2SO3佔原蒸煮前藥品添加量之26%，回收Na2CO3佔原藥品添加量之94%，Al (OH)3之回復量爲80%，工業設備比試驗室爲完善時，回收率尚有希望提高。
The purposes of this study are:
(1) To investigate the sodium sulfite pulping of rice straw and the repeated use of waste liquor as part of the cooking liquor.
(2) To investigate the distribution of sillica originally contained in rice straw, between pulp and Waste liquor.
(3) To investigate the possibility of the recovery of cooking chemicals using the SONOCO sulfite recovery process.
It is intended that from these studies some guidelines on sodium sulfite pulping of rice straw and on waster liquor recovery could be drawn for the local paper industry so to replace the currently used soda pulping process.
The results are:
(1) Washed straw gives a better pulp.
(2) By comparing the results of soda cooks at 8% and 10% total alkali (as Na2O), and sodium sulfite cooks at 8% and 10% total Na2O, the pulp from Na2O sulfite cook gave a higher yield (before and after bleaching), better strength and opacity.
(3) Repetitive uses of waste liquor, at one third of the volume of cooking liquor, do not affect the yield whilst do give pulp higher tensile, tear, opacity and silica content. The higher residual silica in pulp and thus less ailica in waste liquor would give less trouble in evaporation and recovery system.
(4) The bleached pulp has a lower opacity than unbleached pulp; but the figures are still much higher than those for wood pulp and bleached sulfate bagasse pulp.
(5) With a simple set-up of burning the concentrated waste liquor, after mixing with aluminum hydroxide, it is found possible to recover 94% of Na2CO3 and 26% Na2SO3 (based on the chemicals is the cooking liquor). The recovery of aluminum hydroxide is 80%.
It is believed that with professionally designed industrial scale equipment the SONOCO process which with aluminum hydroxide as an intermediate can be adapted to a small scale pulping system, could be applied to rice straw neutral sulfite waste liquor recovery as one of the ways of solving the pollution problem.
