蛭石尾砂在燃煤固硫除尘中的利用

The Application of Vermiculite to the Desulphurization and Dusts Clearing During Coal Combustion

在对新疆且干布拉克蛭石矿尾矿进行矿物学研究的基础上 ,进行了高温膨胀实验 ,结果表明 ,蛭石尾砂的膨胀倍数因粒度的增大、时间的延长而提高 ,较为理想的膨胀温度在 95 0～10 5 0℃之间。利用碳酸钙为固硫剂、膨润土为粘结剂、蛭石尾砂为膨胀添加剂对肥城烟煤进行高温燃煤固硫实验。结果表明 ,蛭石尾砂能较大幅度地提高肥城烟煤的固硫率。经XRD、SEM和EDX等分析表明 ,燃煤灰渣的主要固硫物相为硫酸钙 ,且因燃烧条件、添加剂和燃煤种类的差异而以不同的形态存在。蛭石尾砂对燃煤固硫促进机理可解释为营造型煤内部氧化气氛 ,抑制新物相硫酸钙的分解。

Studies show that some special chemical and physical properties of environmental mineral materials can play an important role in reducing SO 2 and removing dust during the combustion of low rank coal. One of the most important aims of this paper is to study the mineralogical characteristics of vermiculite from vermiculite mill gangue and apply this mineral to the desulphurization and dust clearing additives during coal combustion. The authors studied the desulphurization stimulative capacities of vemiculite at different high temperatures. In this new kind of desulphurization additives, CaCO 3 is the main desulphurization composition, bentonite serves as adhesive, and vermiculite plays the inflation role. The new additive has high desulphurization ratio ranging from 71% to 97%. The desulphurization product-cinder-was investigated and studied by XRD, optic microscope, polariscope microscope, glistening microscope and SEM-EDX. The main compositions are SiO 2, CaSO 4, glass and oxides, which mainly contain iron. The content and shape of CaSO 4 are determined by coal types, combustion temperature, desulphurization additives content and types, etc. Desulphurization mechanisms of new additive made mainly of vermiculite are as follows: inflating of vermiculite at high temperature makes the inside of briquette looser, and more O 2 gas can permeate the outer part of briquette and enter the interior; high concentration of O 2 play an important role in forming CaSO 4 and restraining the decomposing of CaSO 4.