Oxygen-enriched coal powder smelting reduction laterite nickel ore process and smelting reduction furnace

Abstract

The invention provides a technology for reducing laterite nickel ore by smelting oxygen-enriched pulverized coal and a smelting reduction furnace. The technology comprises the following steps: dewatering laterite nickel ore until the water content is reduced to be less than 22%; adding the dewatered laterite nickel ore to the smelting reduction furnace, and adding a flux at the same time; injecting the oxygen-enriched gas, a reducing agent and fuel into a bath mixing area of the smelting reduction furnace at the flowing speed of 180-280m / s through a multi-channel injecting gun; increasing the temperature in a bath of the smelting reduction furnace to be 1450 to 1550 DEG C in order to realize bath smelting of the materials in the smelting reduction furnace and generate nickel-iron alloy and smelting slag, wherein the bath mixing area includes the nickel-iron alloy and the smelting slag; discharging the smelting slag from a slag hole, and discharging the nickel-iron alloy through a metal outlet. According to the technology, a laterite nickel ore smelting technology and device is provided and is compact in process, few in manpower quota, high in environmental protection capacity, and low in production cost.

Description

technical field [0001] The invention relates to the field of nonferrous metallurgy, in particular to a process for smelting and reducing laterite nickel ore with oxygen-enriched coal powder and a smelting reduction furnace. Background technique [0002] Laterite nickel ore is formed by long-term weathering and leaching metamorphism of nickel-bearing peridotite in tropical or subtropical regions. Due to weathering and leaching, the ore deposit generally forms several layers, the top layer is a colluvial layer (iron cap) with low nickel content; the middle layer is a limonite-type laterite nickel layer, which contains more iron, less silicon and magnesium, and low nickel. The cobalt is relatively high, and the wet process is generally used to recover metals; the bottom layer is a humus layer mixed with gangue (including silicon-magnesium-nickel ore-type laterite-nickel ore), which contains high silicon and magnesium, low iron, high nickel, and low cobalt. Generally, it is tre...

AI Technical Summary

Problems solved by technology

[0012] Disadvantages of RKEF process: cobalt in nickel ore cannot be recovered, and it is not suitable for nickel oxide ore with high cobalt content

[0034] Disadvantages of the shaft furnace process: when the material reaches a certain metallization rate after pre-reduction, it is easy to stick under high temperature extrusion, and the furnace wall of the shaft furnace is prone to furnace knots, which cannot be removed in a hot state, and the furnace must be shut down for cleaning. As a result, the operation rate of the process is low and the production cost is high; and the fluidized bed is prone to sticking and clogging, and cannot run continuously; during production, a certain amount of coke needs to be added to form a material column, which is costly and has limitations in the energy structure

[0047] The problems existing in the Vanyukov furnace are: 1) The temperature of the melt is not easy to maintain, and the channels of nickel matte and slag are often blocked by furnace knots due to insufficient temperature, and the furnace must be shut down for cleaning, which affects normal production; The reaction of oxygen and melt is prone to local peroxidation, and overoxidation will lead to foamy slag, which will cause splashing and threaten safe production in severe cases; The melt is easy to overflow from the gap of the water jacket, making the operating environment, polluting the atmospheric environment around the enterprise, and adversely affecting the survival of people and organisms; 4) When the Vanyukov furnace is working, it is cooled by the water jacket Make the melt hang slag on the surface of the water jacket, so as to avoid direct contact between the water jacket and the melt for a long time, but this kind of slag is not stable, once the water jacket breaks and water enters the melt, it will seriously endanger production safety and personal safety; 5) The copper water jacket partition wall of Vanyukov furnace divides the metallurgical furnace into smelting and reduction areas. The two sides of the partition wall are respectively oxidizing atmosphere and reducing atmosphere. The copper water jacket partition wall has the problems of poor chemical stability and short service life. Furnace knots are prone to occur in the wall area

A large amount of pulverized coal and oxygen are injected over the molten pool. Due to the need to control the reducing atmosphere in the furnace and the influence of negative pressure in the furnace, the pulverized coal injected will inevitably be sucked into the ascending flue without complete combustion; At the same time, due to the violent tumbling of the molten pool in the furnace, the top-firing lance is easily bonded or corroded by erosion, and there is a danger of water leakage, which brings risks to the stable operation of the melting furnace

[0052] The patent claims only specify that the side blowing lance sprays coal powder and oxygen into the molten pool, and does not further propose the structure of the lance

At the same time, there is no claim for the distance between the spray guns on both sides and the position of the spray guns in the molten pool, which is the core feature of the side-blown molten pool melting process. The electrode insulation area is reserved, and secondary energy and electric energy are still consumed.

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