Microwave-fuel combined heating-type coal-based direct reduction method and rotary hearth furnace

Abstract

The invention discloses a microwave-fuel combined heating-type coal-based direct reduction method and a rotary hearth furnace. The method comprises the following steps of drying and pre-heating materials, reducing the materials by a fuel combustion method, and further reducing the materials by a microwave radiation method, wherein a reducer for reducing the metal oxide into metal is fixed carbon in the materials. The rotary hearth furnace is used by the above method. The rotary hearth furnace has the advantages of simple structure, low cost, high metallization rate, and realization and popularization easiness.

Description

technical field [0001] The invention mainly relates to the field of coal-based direct reduction rotary hearth furnaces, in particular to a coal-based direct reduction method using fuel and microwave combined heating with microwave fuel and a rotary hearth furnace based on the method. Background technique [0002] Coal-based direct reduction rotary hearth furnace technology uses coal as a reducing agent to reduce metal oxides in ore materials to metals under non-reflow conditions. This method does not rely on coking coal resources, and compared with traditional steel production processes, it can greatly reduce pollutant emissions, and its products can replace scrap steel as raw materials for smelting high-quality steel in electric furnaces. Therefore, the market prospect of this process is broad, and it is one of the main directions for the development of iron and steel smelting in the future. [0003] Common methods of direct reduction production include gas-based shaft fur...

AI Technical Summary

Problems solved by technology

It can be seen that there are obviously many problems to be solved in the conventional rotary hearth furnace technology, otherwise it will face the danger of being eliminated.

[0008] 2) Another important problem in the conventional rotary hearth furnace technology is that even if the material 3 stays in the furnace for a long enough time to ensure a sufficiently high reduction rate of the metal oxides in the lower material 3, the flue gas from fuel combustion contains a lot of CO 2 The gas in the oxidizing atmosphere will oxidize the reduced metal in the upper material 3 again

The results show that the all-microwave method has very low energy efficiency when the furnace temperature is low, which will lead to higher production costs

[0012] 2) The investment cost of a rotary hearth furnace device with full microwave heating is dozens or even hundreds of times higher than that of a conventional fuel combustion heating rotary hearth furnace device, especially in today's high-power microwave heating device price In very expensive cases, the investment cannot be afforded by the business

Moreover, the service life and maintenance cost of microwave devices will have a great impact on production operation and economy, which is another reason why it is difficult to realize industrialization of microwave devices.

[0013] 3) The current all-microwave method is only a prototype, which only provides a concept, and there is no complete design that can match it and can be industrialized. Many technical problems, such as flue gas emission under microwave reduction, furnace pressure control, etc. There has never been any research

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