Study On Papermaking Green Liquor Synthesize Calcium Carbonate Whisker

In recent years, with the rapid development of economy in our country, the demand of paper is rising, so more and more paper mill are built. At the same time, the paper industry is facing some difficult and problems about environment and resource waste. Papermaking is usually divided into pulping, papermaking, coating and processing. Papermaking green liquor is a kind of important intermediate product of pulping, It is alkaline pulping black liquor evaporation and concentration, extraction, resulting from the burning of the melt dissolved in dilute liquid or water to form white mud.The main ingredient of white mud is calcium carbonate,which show three polymorph with aragonite, calcite and vaterite. white mud is calcite and it is show steady-state hexagonal pattern with a low value of utilization. Aragonite is metastable environment friendly material,it show whisker-like with a high value of utilization.The paper mainly study on papermaking pulp synthesize aragonite whisker rather than calcite. Experiment use main analytical test are XRD?SEM?ICP ?pH and so on. This paper roundly study Optimum reaction parameters, effect of main impurities and petreatmented papermaking green liquid synthesize aragonite whisker.Aragonite whisker is a metastable calcium carbonate crystal, a certain extent,its growth affected by the environment. Therefore, this paper firstly analyze effect of reagent to the reaction system reaction parameters. The result find the optimum reaction temperature is 80 ?, the reaction was the best way to feed double the addition, the optimal substrate solution Ca2 + concentration was 0.4mol/L, the best reaction system stirring speed is 350 r / min, calcium carbonate is added to the reaction mixture as a seed crystal form of the product is not obvious.This article identifies the main component of green liquor and the main impurity by chemical analysis method.Experimental results show that the green liquor impurities is complex.This paper mainly uses analog green liquid component method study the effect of papermaking green liquor influence of impurities on calcium carbonate whisker. Sulfur-containing compounds are the most abundant green liquid impurities.However, aragonite is higher than 75% when sulfur compounds less than 20%, and the calcium carbonate products morphology is balance and the aspect ratio is ideal. The main product of the product becomes granular calcite when the paper after the green liquor sulfur compound content higher than 30%.Silicon impurities are the main influence factor on of calcium carbonate polymorphs by simulation green liquid ingredient. The result show that the product is granular calcite when the silicon concentration of green liquor higher than 0.4g/L. MgO added reaction system can effectively suppress the influence of silicon on calcium carbonate crystals. when MgO of 0.7g/L was added reaction system, the analog green liquid silicon content of 0.4g / L, the aragonite content is 76%. Even green liquid silicon content reach to 0.9g/L, the product still has a small amount of aragonite. The all products become calcite,when the analog paper green liquid silicon content is 1.2g/L.Papermaking green liquor have a higher silicon concentration. The product is calcite when real green liquor involved in the reaction. Some pretreatment were used to reduce the content of silicon in the green liquor, and in the course of the reaction MgO was added to suppress the influence of silicon. The result can be successfully prepared aragonite content of about 40%. And the product is valueable than the white mud from papermaking mill.