In order to address issues such as cementitious agglomeration, difficulty in dispersing inclusions, and poor slurry homogeneity encountered in the conventional mixing preparation of high-concentration filling slurry, the development of new, efficient high-concentration mixing equipment is crucial. Based on theoretical analysis, this paper derives calculation formulas for the mixing power and rotational speed of the high-concentration mixing tank. Through finite element analysis, the stress distribution and vibration mode shapes of the mixing system are obtained, leading to the determination of the structure and key technical parameters of the high-concentration mixing tank. Artificial ore proportioning tests were conducted on a $\varnothing 2500\mathrm{mm}\times 2500\mathrm{mm}$ high-concentration mixing tank to investigate the effects of mixing time, rotational speed, and component ratio on mixing uniformity, mixing power, and the compressive strength of the backfill. The research results demonstrate that the developed prototype of the high-concentration mixing tank meets the requirements for mixing and preparing high-concentration slurry for total tailings cementitious backfilling. The findings of this study can provide references for related engineering equipment research.