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

Abstract

The present invention relates to a method and apparatus for thermal treatment of sulfide ores, in which the solids are heated in a fluidized bed reactor (1) to a temperature of about 450-1500°C. In order to improve the energy utilization, it is proposed to introduce the first gas or gas mixture from below into the mixing chamber (7) of the reactor (1) through a gas supply pipe (3) which is at least partially fluidized by the supply fluidizing gas Surrounded by a fixed annular fluidized bed (35). Adjust the gas velocity of the first gas or gas mixture and the fluidizing gas for the annular fluidized bed (35) so that the particle Froude number in the gas supply pipe (3) is 1-100, and the annular fluidized bed (35) The Froude number of the particles in the mixing chamber (7) is 0.02-2, and the Froude number of the particles in the mixing chamber (7) is 0.3-30.

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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