|
The traditional sodium vanadium roasting process resource utilization, high energy consumption and serious environmental pollution effluents urgent needs, Institute of Process Engineering Asia-based molten salt chemical and metallurgical clean production technology platform, long-term accumulation, made significant originality Asian molten salt method vanadium slag cleaner production processes, new technology can be relatively mild reaction conditions, to achieve vanadium slag vanadium, chromium efficient resource sync extraction. In this study, vanadium slag Asian molten salt reactor translational research based on the preliminary work for vanadium, chromium component subsequent separation problems, according to the equilibrium crystallization separation on the basis of material, measured by isothermal method involves new technology system solubility data solubility phase diagram was constructed, established Asian molten salt diverse and complex system of sodium vanadate, sodium nitrate, sodium chromate crystallization separation method for sub-molten salt method of cleaner production of vanadium slag separation process design and optimization of theoretical basis. Main contents are as follows: (a) a new process for the sub-molten salt sodium vanadate, sodium nitrate and sodium chromate separation process design, determination of 40 ℃ and 80 ℃, NaOH-NaNO 3 -Na 3 VO 4 -Na 2 CrO 4 -Na 2 SiO < sub> 3 -H 2 O system and sub-system of the solubility data, and draw the corresponding solubility phase diagram. Based on the above basic data, design of a vanadium, sodium nitrite and sodium chromate crystallization separation method, the NaOH concentration is less than 300g / L when the cooling crystallization method can be used to achieve separation of sodium vanadate; After the separated sodium vanadate The solution was evaporated to 400g / L, and then cooled down to 40 ℃ nitrate crystals can achieve separation of the crystallization mother liquor was evaporated to continue the concentration of NaOH was 500g / L, at 80 ℃ crystallization separation, the separation can be achieved sodium chromate. (2) for the design of sodium vanadate, sodium nitrate and sodium chromate crystallization separation methods for process simulation. By measuring 40 ℃, 60 ℃ and 80 ℃, a mixed solution of three temperatures and cooling process, the evaporation concentration, confirmed the feasibility of the crystallization process. (3) based on the solubility data and the solubility of the phase diagram, a view showing a multi-system interaction between substances exist, discusses its separation process of the crystallization. (4) to simulate the NaOH-H 2 O, NaOH-NaNO 3 -H 2 O and NaOH-Na 3 VO 4 -H 2 O system of ion hydration, obtained various ionic radius and hydration hydration number, and, based on the data obtained, explaining NaOH solution, the solubility of sodium nitrate and sodium vanadate decreases with increasing alkali concentration trend.
|