The use of a combined additive consisting of silica-containing additives “F” (thinning) and “S” (accelerating castable hardening) instead of the previously used silica-containing additive “A” and a mixture of dispersing additives based on polyethylene glycol in low-cement silicon carbide castable allows to improve the castable workability by increasing (in 5.4 times) the flowability of a freshly prepared castable, and increase by 1.2 and 1.1 times the cold crushing strength of heat-treated at temperatures of 110 and 1 580 °C, respectively, castable samples from low-cement silicon carbide castable with practically equal values of open porosity (15.8% and 16.0%). The petrographic studies of the castable sample microstructure after firing at a temperature of 1 580 °C showed that the investigated silica-containing additives “F” and “S” contribute to the denser and more uniform structure formation. As a result of the carried out research, the manufacturing technology of a low-cement silicon carbide castable was improved, of which the production was mastered at JSC “URIR named after A. S. Berezhnoy”.