Abstract:

The separation of residual carbon and slag particles from coal gasification slag is a key prerequisite for its extraction and utilization. This paper studied different types of carbon-rich and slag-rich products obtained by using sieving, airflow classification and acid washing/calcining methods. The characterization of carbon and slag in the products was discussed and their reinforcing and filling properties for rubber as fillers were investigated. The results showed that the carbon-rich or slag-rich products obtained by different methods had different properties. Sieving could realize a certain degreed of separation of carbon in gasification slag. Airflow classification could obtain carbon-rich particles with smaller particle size and larger specific surface area. High purity of carbon and slag was obtained from acid washing and calcining. The large specific surface area of the residue carbon in coal gasification slag provided abundant contact sites for its combination with rubber, which played a reinforcing effect similar to carbon black. The microsphere particles in the carbon skeleton could reduce the adsorption of sulfidation accelerators and sulfidation agents, and shorten the curing time. Calcium sulfate in gasification slag could promote the generation and transfer of active sulfur and increase the crosslinking density of rubber compound. Compared with rubber composites without fillers, rubber filled with gasification slag could significantly improve the mechanical properties of rubber composites. Among them, the carbon-rich slag obtained from airflow classification had the best reinforcing properties after filling, the tensile strength of the prepared rubber composites was increased to 13.92MPa, and the 300% modulus was 3.75MPa, which were better than other types of carbon-rich or ash-rich raw materials. This study improved the understanding of the properties of carbon and slag of the gasification slag, and contributes to the development of the technology for the preparation of gasification slag-based rubber reinforcing fillers.

Key words: coal gasification slag, separation of carbon and slag, sieve, airflow classification, rubber filler

摘要：

煤气化渣中炭灰分离是实现其分质利用的重要前提。本研究利用筛分、气流分级及化学酸洗/煅烧获得了不同类型的富炭和富灰产物，对产品中的炭灰特性进行分析，并探讨其作为填料对橡胶的补强填充性能影响。结果表明，不同方法所得的富炭或富灰产物性质不同，筛分可实现气化渣中的炭-灰一定程度的分离；气流分级则可得到粒径较小且比表面积较大的富炭颗粒；酸洗/煅烧可制备纯度较高的炭和灰。煤气化渣中残炭较大的比表面积为其与橡胶结合提供了丰富的接触位点，起到了类似炭黑的补强效果，其炭骨架内附着的微珠颗粒能够减少对硫化促进剂和硫化剂的吸附，缩短硫化时间。气化渣中硫酸钙可以促进活性硫的生成和转移，提高胶料的交联密度。相较不添加填料的橡胶复合材料，气化渣填充橡胶可显著提高橡胶复合材料的力学性能。其中，气流分级所得的富炭渣的补强填充性能最好，其制备的橡胶复合材料拉伸强度提高到13.92MPa，300%定伸应力为3.75MPa，均优于其他类型富炭或富灰原料。本研究提高了对煤气化渣中炭灰特性的了解，有助于煤气化渣基橡胶补强填料制备技术的研发。

关键词: 煤气化渣, 炭灰分离, 筛分, 气流分级, 橡胶填料