Constant temperature rotary roasting system heated by molten salt and technology thereof

Abstract

The invention provides a constant temperature rotary roasting system heated by molten salt and a technology thereof, wherein a molten salt circulating pump is arranged on the upper part of a molten bath, the molten salt circulating pump is connected with a molten salt heater, the molten salt is connected with a drum reactor inlet collection case from the molten salt heater, a drum reactor outlet collection case is connected with the molten bath, a drum reactor heat exchange tube is arranged in the drum reactor, a material inlet of the drum reactor is communicated with a material comminutor, and a clinker outlet and a heat exchanger exhaust port are arranged on the other end of the drum reactor. By continuously and violently tumbling and bumping of the materials in the drum, the system is in favor of heating uniformity of the materials, shortens reaction time, and simultaneously combines a granulation technology to effectively avoid a bonding phenomenon on a wall surface appeared in the material roasting process. by using the molten salt as a heat exchange medium and utilizing good heat stability and high heat transfer coefficient of the molten salt, the technology can well control temperature homogeneity in the drum reactor, to make the product have high extraction efficiency and to make the clinker have good quality.

Description

technical field [0001] The invention belongs to the technical field of heat exchange reaction of solid materials in the chemical industry, and in particular relates to a constant temperature rotary roasting system heated by molten salt and a process thereof. Background technique [0002] Fly ash is a solid waste discharged from coal-fired boilers with flue gas. It is a glassy solid particle formed by melting impurities and quenching when coal is burned at high temperature. The main chemical composition of fly ash is Al 2 o 3 and SiO 2 , the sum of the two amounts to more than 80%. Comprehensive utilization of fly ash to extract alumina is a high value-added utilization of secondary resources. The research has shifted from theoretical and experimental research to pilot and industrial test research, but the technical routes available for industrial production are still very limited. [0003] The alkali roasting method has made some progress in industrial application due t...

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Problems solved by technology

[0003] The alkali roasting method has made some progress in industrial application due to its simple process, but because of its inherent defects, the whole process is immature or uneconomical, making production unsustainable; Corrosion requirements are high, the investment cost is huge, and the research has been in the theoretical and laboratory stages, and the road to industrialization is still relatively long; while the ammonium sulfate method, which has a relatively mild reaction and can control the amount of slag, has not yet realized industrial production, mainly because the process It has been unable to solve the problem that ammonium sulfate and fly ash are mixed and roasted to produce aluminum sulfate or the production rate of aluminum ammonium sulfate is not high: the melting point of ammonium sulfate and aluminum ammonium sulfate is low, and they quickly form a molten state during the reaction process, which is easy to stick to the reactor wall, and ammonium sulfate is easy to decompose, after decomposition, it will not be able to combine with Al in fly ash 2 o 3 react, resulting in Al 2 o 3 The extraction rate is not high

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