Study on Mix Proportion Optimization of Red Mud-Based Geopolymer Based on RSM

Due to its low activity, tiny particle size, and high alkalinity, Bayer red mud has turned into a solid waste that is now challenging to dispose of. To accomplish resource use of red mud solid waste, the alkali excitation technique was used to make the red mud base polymer after the activated red mud was generated using the calcination method. The response surface approach was used to examine the effects of the alkali content, water glass modulus, and granulated blast furnace slag (GBFS) powder content on the mixture’s initial setting time and 28-day compressive strength of red mud base polymer. The test results show that with the increase of GBFS content, the 28-day compressive strength of the red clay-based polymer gradually increases, and the modulus of elasticity of water glass and the alkali content also gradually increases. The blend has a shorter initial setup time as a result of the increased GBFS concentration. With the increase of water glass modulus and alkali content, the mixture’s initial setting time initially drops and then rises. After optimization using response surface methodology, the optimal mix ratio for the red mud-based geopolymer was determined as follows: 9.2% GBFS, 8.4% alkali content, and a water glass modulus of 1.8. In these circumstances, the red mud-based geopolymer’s 28-day compressive strength was 60.3 MPa, and the mixture’s first setting time was 83.5 min.