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摘要：碳酸钙（Calcium carbonate）是一种无机化合物，俗称灰石、石灰石、石粉、大理石、方解石，是石灰石的主要成分，其分子式为CaCO3。呈中性，基本上不溶于水，溶于酸。碳酸钙是一种重要的粉体材料，也是重要的化工原料之一，因其无毒和使用性能良好而被广泛应用应用于塑料、橡胶、造纸、油墨、涂料等行业，是一种附加值高、经济效益好、应用范围广的产品。我国每年的碳酸钙耗量巨大。31616
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造纸黑液的主要成分是木质素和聚糖等，木质素是一种含有各种生物学稳定的复杂键型的高分子有机化合物，难以直接进行生物降解，黑液中的木质素多数是由数个苯丙烷单元组成。所以本论文采用先碱化黑液的方法，在黑液中加入Ca（OH）2溶液，调节PH=12左右，然后提取碳酸根，制备碳酸钙，通过无水甲醇、二氯甲烷、乙酸乙酯、石油醚打浆纯化和水洗等方法尽量去除碳酸钙中的杂质，再测定其中碳酸钙，杂质的含量。最后酸析滤液，调节PH=1左右使苯丙烷单元转变成不溶性的游离酚的状态从黑液中析出，再经过沉淀、过滤，进而沉淀提取木质素。
毕业论文关键词：碳酸钙，打浆，钙含量，酸析
The research of preparing CaCO3 by papermaking black liquor
Brief:Calcium carbonate is an Inorganic compound.Generally speaking,it is the main ingredient of limestone,known as greystone、limestone、mountain flour、marble and calcite.The molecular formula is CaCO3 which is presented neutral ph value.And it almost insoluble in water but soluble in acids.CaCO3 is created by calcium ion and carbanion,so it’s not only called calcium salt but also carbonate.Calcium carbonate are widespread in the earth,exist in aragonite、calcite、chalk、limestone and so on.Besides that,it’s also the major ingredient of animals’ bones and shells.In addition to that,Calcium carbonate is an important powder material and a part of chemical materials.It’s ulitized in many aspects because of its characteristics of non-toxic and well usability,commonly used in plastic、rubber、papermaking、printing ink、painting and so on.High value、good economic benefits and wide range of application are all advantages of the product.So there is a great amount of annual consumption of calcium carbone in China.
The main components of black liquor are lignin and glycan etc.Lignin is a water-soluble polymer that contains all kinds of stable and complicated bond types in biology. Most of lignin is composed of so many phenylpropane-units that it’s difficult to adopt biodegradation.
So the paper adopt a way that alkalify the black liquor firstly,that is add moderate Ca(OH)2 to the black liquor and adjust PH=12 or so.Then extract the carbonate to prepare calcium carbonate.At the same time,to wipe off the impurities from the calcium carbonate by beating、purification and washing with absolute ethyl alcohol、dichloromethane、ethyl acetate and petroleum ether.The next step is to assay the content of calcium carbonate and impurities respectively.Finally,to acid out filtrate,adjust PH=1 to convert the phenylpropane-unit into the insoluble free phenol and separate out it from the black liquor.Then extract lignin by precipitating、filtrating and precipitating again.
Keywords:Calcium carbonate,beating,The calcium content,acidification
目录
1、绪论 1
1.1开题依据 1
1.2碳酸钙的概况 1
1.3碳酸钙的性质 2
1.3.1碳酸钙的物理性质（25℃，100KPa） 2
1.3.2碳酸钙的化学性质 3
1.4碳酸钙的分类 4
1.4.1按微观排列分类 4
1.4.2按生产方法分类 5
1.4.4纳米碳酸钙Nano Calcium Carbonate 7