Method and device for smelting molten salt during aluminum oxide production

Abstract

The invention discloses a method and a device for smelting molten salt during aluminum oxide production. According to the invention, the solid molten salt at a normal temperature is introduced into a molten salt storage tank, a steam heater is arranged in the molten salt storage tank, the steam with a pressure of 3-4MPa and a temperature of 250-270 DEG C is introduced into the steam heater, in order to smelt the heated molten salt by heating to higher than 142 DEG C, and then the smelted molten salt is pumped into the next process. The method and the device of the invention have the following advantages: the smelting conditions of the molten salt can be satisfied, the system is simple, the existing apparatuses of aluminum oxide plant can be fully used, the apparatus investment is reduced, the power supply is reduced, the reliability is high, the service life is long, the operation and management are convenient, the maintenance is easy and the like.

Description

technical field [0001] The invention relates to a molten salt melting method and device in alumina production, and belongs to the technical field of molten salt heating in a pipeline dissolution production alumina system. Background technique [0002] Molten salt is a mixture of various nitrates, the main component is: NaNO 2 (40%), NaNO 3 (7%), KNO 3 (53%), melting point: 142°C, boiling point: 680°C, operating temperature range: 350-530°C, specific heat: 1.424kJ / kg·°C. [0003] At present, in the alumina production system using the pipeline dissolution process, the molten salt is used as a high-temperature heat carrier to indirectly heat the pulp in the pipeline dissolution device, and conduct heat exchange with the pulp, so that the temperature of the pulp increases and the temperature of the molten salt decreases. The cooled molten salt is returned to the molten salt heating station, reheated in the molten salt heating furnace, and recycled. Since the molten salt is s...

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Problems solved by technology

Although this method can achieve the purpose of molten salt melting, it needs to set up an electric heater. The electric heater not only has the problem of large investment, but also has the problems of short service life and difficult maintenance; in addition, due to the If the power is large, it is necessary to set up a special power supply and distribution device, which undoubtedly requires a large investment

Moreover, after the molten salt is melted, it is pumped into the molten salt furnace for heating, and the configured electric heating system is out of service. During normal production, this expensive electric heating system configured will always be in an idle state, which will undoubtedly cause waste of resources

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