Synthetic salt rock prepared by molten salt crystallization and its physical and mechanical properties

Physical simulation is an important research method for salt cavern energy storage construction technology. However, its progress is constrained by lack of effective model salt. Exploratory experiments were conducted to prepare salt rock by molten salt crystallization. A well-made synthetic salt rock was obtained from repeated adjustment of staged cooling conditions and controlled crystal growth procedures. Samples were taken for microscopic, physical, and mechanical tests, and compared with natural salt rock. SEM, CT and p-wave velocity results show that synthetic salt rock achieved crystallization. Its crystal structure, grain size and intercrystalline relationship are consistent with those of natural salt rock. Its density distribution is uniform and compaction is good. X-ray results prove a high crystallinity and stable mineral composition. Porosity of synthetic specimens ranges from 2.3% to 5.9%, permeability is in the range of E−13 to E−16 m2. Uniaxial compression stress-strain curves, strengths, deformation modulus and poisson's ratios are close to those of natural salt rock. It has obvious ductility and damage occurs after dilation deformation. We initially illustrate energy storage and heat storage-transfer principles of molten salt. The mechanism of layered growth in molten salt crystallization is revealed. The findings provide new insight on salt rock preparation, crystallography, molten salt and salt cavern study. •Using large salt blocks drilled in site to simulate cavern formation is difficult.•Analogs properties prepared by compaction or binder differ from natural salt rock.•Conducted molten salt crystallization to prepare salt rock from crystal level.•Crystallized synthetic salt with characteristics close to natural salt was gained.•Mechanisms of energy storage and crystallization of molten salt are analyzed.