隔膜电解法处理草浆黑液

The treatment of black liquor from straw pulp by electrolytic process

进行了隔膜电解法处理草浆黑液的可行性实验研究 .隔膜电解法实验采用铸铁作牺牲阳极 ,石墨作阴极 ,多孔性的滤过式隔膜将阳极区与阴极区分开 ;阳极及其附近有铁的氧化与水解反应 ,碱木素的取代反应 ;阴极有析氢反应 ;水分子和钠离子在势场力作用下透过隔膜从阳极区进入阴极区 ,碱木素分子被隔离在阳极区 ;阳极区不断加入黑液 ,取走木素沉淀 ,阴极区不断取走回收碱液 ,从而实现碱液与木素的分离 .在电流为 1A、电压为 8V及室温条件下电解 12h ,阳极区黑液的色度、悬浮物及COD的去除率分别为 6 6 .4% ,75 .3%和 94% ,碱回收率达到 94%以上 .实验结果表明 ,作为一种处理黑液的碱回收技术 ,隔膜电解法处理草浆黑液比较容易直接嫁接到制浆工艺中 。

Experimental study of feasibility on black liquor from straw pulp by electrolytic process has been carried out. The cast iron is used as anode and graphite electrode as cathode in the experiments. Electrolytic vessel is separated into both cells of anode and cathode with porous filtration membrane. There are reactions of oxidation and hydrolysis of Fe and substitution of alkaline lignin in the anode, and there is hydrogen evolution reaction on the cathode. H 2O and Na + move from the anode into the cathode through the membrane with the action of potential energy, and only lignin is left over in the anode. The process can make lignin separated from alkaline solution when black liquor is poured into the anode and alkaline solution is taken out from the cathode continually. The removal rate of colourity, SS and COD of black liquor can reach 66.4%, 75.3% and 94% respectively, and alkali recovery can be up to 94% at normal temperature and in treatment conditions ( I =1 A, V =8 V, t =12 h). The experiments show that electrolytic process can be replanted onto pulping processes easily as a practical technique of alkali recovery and maybe is a new way of treating black liquor from straw pulp.