Method and plant for the heat treatment of sulfidic ores using annular fluidized

Abstract

The invention relates to a method and a plant for the heat treatment of sulfidic ores, in which solids are heated to a temperature of approximately 450 to 1500 DEG C in a fluidized bed reactor (1). In order to improve the energy utilization, it is proposed to introduce a first gas or gas mixture from below through a gas supply tube (3) into a mixing chamber (7) of the reactor (1), the gas supply tube (3) being at least partly surrounded by a stationary annular fluidized bed (35) which is fluidized by supplying fluidizing gas. The gas velocities of the first gas or gas mixture as well as of the fluidizing gas for the annular fluidized bed (35) are adjusted such that the particle Froude numbers in the gas supply tube (3) are between 1 and 100, in the annular fluidized bed (35) between 0.02 and 2 and in the mixing chamber (7) between 0.3 and 30.

Description

technical field [0001] The invention relates to a process for the thermal treatment, in particular of sulphide ores, in which fine-grained solids are treated in a first fluidized bed reactor at a temperature ranging from 450°C to about 1500°C, and to a corresponding plant. Background technique [0002] A method and a device of this type for the thermal treatment of gold-bearing sulfide ores are known, for example, from DE 19609286 A1. In this case, the ore is fluidized with an oxygen-containing gas in a circulating fluidized bed of a roasting reactor, and the metal sulfides are converted to metal oxides to obtain SO-containing 2 exhaust gas. [0003] It is also known to roast sulphide ores such as sphalerite with a supply of air in fixed fluidized bed furnaces at temperatures of 500-1100°C. When roasting sphalerite in a fixed fluidized bed furnace, up to 1000 metric tons of sphalerite can be processed per day. [0004] The energy utilization of the heat treatment achieved...

AI Technical Summary

Problems solved by technology

One reason is: due to the low degree of fluidization, both mass and heat transfer are relatively moderate

Also, in the case of a fixed fluidized bed, the fines are removed from the reactor too quickly, so the residence time in the unit is not sufficient for complete reaction

In circulating fluidized beds, despite good mass and heat transfer conditions, the problem is particularly pronounced in this case because of the high degree of fluidization

Because the sulfide ore used for heat treatment such as gold ore, sphalerite or concentrate is increasingly refined, for example, the proportion of particle size less than 45 μm is 75%, it is difficult to achieve sufficient roasting effect with known methods and devices

[0005] In addition, in known methods and devices, the temperature in the reactor can hardly be adjusted

This further weakens the roasting effect

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