The Research On Physical Chemistry Properties On Molten Salt Of KNO₃-NaNO₂

Energy is the foundation that mankind rely for existence, along with technical progress and the development of the economy; the demands for energy of human being are growing. Face for the limited energy; make full use of facilities which can transmit and keep energy to economize and the reasonable exploitation which is the key part of the energy problems. While heat transfer and heat storage dielectric is benefit to efficiency improving and costs decreasing. The molten salt is one of most important constitute parts of heat transfer and heat storage dielectrics, and it is also the most valuable part of this paper research.Firstly, in this thesis, the physical properties and structure of molten salt have been briefly introduced. The paper discusses the physical properties of molten salt under eutectic crystal, including the change rule of phase transformation latent heat and melting point. When single crystal salts mixed to be eutectic crystal salt, the mixed salt has a lower melting point, meanwhile, phase transformation latent heat and specific heat would change as well.Thereafter, this paper presents the DTA analysis of potassium nitrate-sodium nitrite system for different proportion ratio on molten salt. Then molten salt of different proportion ratio is evaluated in heat transfer and heat storage, and economic property. As a result, the temperature distribution of different ratio of the melting point of eutectic salt is between 130℃and 220℃. And when the mass ratio at 6:4, it has the best economical efficiency.Then a series physical chemistry property is also researched on the molten salt including viscosity, density and electrical conductivities. Circumgyrate method is carried on to measure the viscosities of mixed molten salts of different ratio and different temperature. The viscosities of mixed molten salts are decreased along with the increasing temperature. Utilizing these date, and via formula Andrade, the unbeknown viscosities of molten salts at specific temperature can be reckoned by two foregone viscosities of mixed molten salts. Using theory of Archimedes, the densities of molten salts at different ratio and temperature can be gained by measuring platinum buoyancy. The results hold that the increasing temperature causing the falling densities and it is show linearity trend. Then the imitate expression p(T)=a+bT received(a and b are different at varied ratio). At last, electrical conductivities are also be measured by CVCC method. The continuing raising temperature augmented the numerical value of conductivity. The variety is slow at commence, but rapid after the temperature exceed 450℃.In China energy-saving strategy is not only the most economical and effective way to achieve sustainable development objectives, but also an important part of the sustainable development. We must have an in-depth understanding of the correlative theory in order to save energy.Therefore, it is of positive significance to generalize and improve energy-saving theory for the work of energy conservation.