Study On Particle Size Distribution Optimization And Application Of Corundum Castable

Corundum alumina has been widely used in steel production as a high quality refractory raw material due to its high purity and refractoriness.The quality of the tabular corundum,the stability of its production,the rationality of the particle ratios,the size and number of pores,the homogeneity of the tissue structure,and the firmness of the interparticle bond all affect the life of the refractory product.This is because other steps cannot repair or reduce the negative effects produced in the initial stages.Therefore,it is of practical importance to study the effect of quality and particle size distribution of tabular corundum on the performance of castables.In this paper,the basic properties,pore structure and particle size distribution of two commercially available domestic and foreign tabular corundums（A/B）were firstly investigated.At the same time,corundum castables were used as the research subjects,and a particle compact stacking model based on the Andreason formula and Dinger-Funk formula（q=0.23,0.26,0.29）was established,and discrete element stacking simulations were performed and experimental forming was used to study the effect of the models on the properties of corundum castables.On this basis,the effect of cement addition on the properties of corundum castables was investigated.The following main conclusions were drawn.（1）Two types of tabular corundum（A/B）with alumina content higher than 99 wt%and corundum phase content higher than 94 wt%,with tabular corundum B having a higher content of alumina and corundum phase than slab corundum A.The d₅₀ in the pore distribution of tabular corundum A is 50μm and the d₅₀ in the pore distribution of tabular corundum B is 30μm,as detected by CT.In the case of no significant difference in other physical properties,the retention rate of cylinder compressive strength of tabular corundum B is higher than that of tabular corundum A.In the size distribution of3-5 mm aggregate,tabular corundum A presents the highest content of 4-5 mm particles with more than 35 wt%,and tabular corundum B presents the highest content of particles larger than 5 mm with more than 35 wt%.In the particle size distribution of1-3 mm and 0-1 mm aggregates,there is no significant difference in the particle size distribution of the two types of tabular corundum.（2）The stacking simulation of the stacking model by the discrete element software shows that the multi-stage pairing has a significant effect on reducing the porosity of the stacking system.For the same q value and more stacking model grades,the porosity generated by the stacking model simulation based on the Andreason formula is higher than that generated by the stacking model simulation based on the Dinger-Funk formula.However,in actual production,the actual porosity is somewhat different from the simulated results due to the effect of water addition and sintering in molding.（3）The above stacking models were actually formed and tested for their properties.The results show that the castable specimens based on the stacking models of Andreason and Dinger-Funk formulas both show that the mechanical properties and slag resistance first increase and then decrease with the increase of q value.The best performance of the castables based on the Dinger-Funk formula with q=0.26.（4）Based on the stacking model of the Digger-Funk formula（q=0.26）,the agastic formulation changed the content of cement fine powder and the effect of cement fine powder content on the performance of the castable.With the increase of cement addition,the CA₆ content generated in the castables increased and produced swelling,which led to the decrease of the castables performance.When the cement content was less,the castables had low strength,which was not conducive to construction.When the cement content is 2 wt%,the corundum castables have the best performance.