Effects of sodium humate and sodium lignosulfonate additives on the plasticity of 3D printing materials for ceramic tableware production

Plasticity is an important physical property of ceramic materials. It demonstrates the ability to shape in traditional ceramic production - made from a mixture containing clay, kaolin-gypsum-quartz. In this article, the effects of sodium humate and sodium lignosulfonate additives on plasticity - characterised by the plasticity index and green flexural strength of 3D printing materials for ceramic tableware production are examined. The results show that when adding sodium humate content from 0.1-0.5 wt.%, the green flexural strength of the mixture increases while the plasticity index does not change significantly compared to the sample without additives. When adding sodium lignosulfonate additive from 0.2-0.9 wt.%, the green flexural strength of the mixture also tends to gradually increase and begins to decrease when increasing the additive content to 1.0 wt.%, the plasticity of the mixture increases after adding 0.2 wt.% sodium lignosulfonate but then tends to decrease with increasing content. Within the testing content range, both additives increase the green flexural strength and do not change the plasticity index much, but the green flexural strength of the mixture when using sodium humate increased higher than sodium lignosulfonate.