SU591524A1 - Method of slag fuming - Google Patents

Description

This invention relates to non-ferrous metallurgy, in particular, to the technology for processing porcine ovo-zinc slags by fusing.

There is a known method of fomying slags, including the treatment of natural gas, mixed with air, by combustion products by blowing them into the melt 1.

The disadvantage of this method is that sublimates are obtained with a low zinc content (below 50%), since in the fusing process there is a large removal of slag particles containing metallic inclusions of zinc and lead. In addition, in the known method does not occur complete combustion of hydrogen and carbon monoxide over the melt due to lack of oxygen, therefore, the burning of hydrogen and carbon monoxide occurs in the area of the superheater and tail heating surfaces of the recovery boiler. This leads to abnormal operation of the waste heat boiler due to the impossibility of stabilizing its thermal conditions.

The purpose of the invention is to increase the degree of metal recovery.

This is achieved by creating a continuous air curtain above the ramp by blowing air in, and the ratio of air to fuel components of the process gases is from 2.3: 1 to 6: 1. Air curtain create a funnel shape. The lower limit of the ratio corresponds to the equivalent of the ratio for the reaction of the burning of hydrogen and carbon in the dust and gas flow at the exit of the furnace. The upper limit of the ratio is taken from the maximum allowable dilution of process gases by AIR.

The created air curtain prevents the removal of slag particles from the melt, and during the furnace loading, these slags are returned to the melt, and also provides for the afterburning of hydrogen and - carbon over the melt.

The proposed method is carried out as follows.

Air is blown through the nozzles located around the perimeter of the p.ch. above the melt, at an angle to it, above the load level, with an outflow rate from 21 to 100 m / s, depending on the nature of the process and in quantitative ratio to the fuel components gases from 2.3: 1 to 6: 1. The air blown into the furnace forms an air curtain that prevents the slag particles from carrying off with the process gases and facilitates their return to the melt. Thanks to this from

The slag particles are additionally extracted zinc and lead and the sublimates are not clogged. In addition, process gases containing hydrogen and carbon monoxide pass through the air curtain, burn down and enter the waste heat boiler at a steady-state temperature regime, which stabilizes the operation of the waste heat boiler.

Example. 60 tons of liquid and 15 tons of cold granulated slag are charged into a slag-raising furnace. The consumption of natural gas for 14 fireboxes with an air excess factor of 0.85-0.9 is 5000.

To create an air curtain, 12,000 air is supplied at a pressure of 350 mm of water. Air is supplied throughout the furnace cross section through nozzles at a speed of 21 m / s. The fusion process is conducted 120 minutes.

As a result of slag fuming by the proposed method, the metal content in sublimates increases by about 13%.

The economic effect from the implementation of the proposed method in one plant will be 250 thousand rubles.

Claims (2)

1. A method of fusing slags, including treating the melt with natural gas combustion products by blowing them into the melt, characterized in that, in order to increase the degree of metal extraction, they create a continuous air curtain by blowing air, and the ratio of air to combustible components of process gases is taken 2.3: 1 to 6: 1. 2. A method according to claim 1, characterized in that the air curtain is created by a funnel-shaped 5 forms Sources of information taken into account in the examination: 1. USSR author's certificate No. 545684, M. Cl. 2 C 22 B 7/04, 1963.