System and method for recovering zinc powder

Abstract

The invention discloses a system and a method for recovering zinc powder. The system comprises a smelting furnace, a pressure reduction settling device, a condenser, a gravity settling device and a cloth bag dust collecting device. The system is reasonable in design and simple in structure, blocking objects on a furnace gas outlet and the zinc powder adhered to condensing pipes can be cleared without stopping production, the operation safety is very high, the operation is convenient, the production benefit is greatly improved, the recovery rate of the zinc powder reaches 100%, impurities and raw material powder mixed in zinc-containing flue gas are removed, the quality of the zinc powder is greatly improved, zinc-containing waste materials can be used as raw materials, resources are saved, and the method is very environment-friendly.

Description

technical field [0001] The invention relates to the field of zinc powder recovery, in particular to a system and method for recovering zinc powder from zinc-containing flue gas produced by zinc-containing waste reduction in a smelting furnace. Background technique [0002] The production of zinc powder by smelting furnaces in my country originated in the 1970s, and evolved from a 600KVA rectangular electric arc furnace to a 800KVA circular electric arc furnace in 2000. By 2006, the first 2000KVA circular electric arc furnace will be built. During this period, the smelting technology has been greatly improved, from the use of a single raw material calcined sand to the production of many kinds of zinc-containing miscellaneous materials through certain treatments and formulas. However, the technology of recovering zinc powder from the zinc-containing flue gas obtained by the reduction reaction in the furnace is very backward. [0003] The backwardness is mainly manifested in ...

AI Technical Summary

Problems solved by technology

[0006] 1. Because the temperature of the zinc-containing flue gas discharged from the furnace gas outlet is firstly high, reaching about 1050-1100 degrees, and in order for the furnace to operate normally, the pressure of the furnace gas outlet reaches 20Pa-30Pa, and the zinc-containing flue gas is originally It is a mixing system. When the mixing system is at high temperature and high pressure, the explosion limit is very high, so explosion accidents often occur when cleaning and powdering, destroying the condenser and baghouse and even injuring people or things;

[0007] 2. Zinc-containing flue gas directly enters the condenser and is cooled very quickly, and part of the zinc vapor will directly turn into solid zinc lumps, which is inconvenient to use screw conveying

Moreover, due to the high pressure of the zinc-containing flue gas, a small amount of materials and impurities in the furnace will be brought into the condenser along with the flue gas, which will affect the quality of the powder, because a condenser is directly facing the furnace gas outlet, so, The temperature and pressure in the condenser are very high, the condensation effect is poor, the temperature of the condensed zinc powder is high, and it needs to be cooled before entering the vibrating screen

[0008] 3. The condensed zinc powder is inconvenient to be conveyed by screw and conveyor belt

In the absence of a decompression device, the cloth bag will be swollen by the airflow, so that the effect of dust collection cannot be achieved, and some zinc powder will be brought into the air, which wastes resources and pollutes the air

[0009] 4. Another big disadvantage is that the zinc-containing flue gas coming out of the furnace will agglomerate when it is cold when it reaches the furnace gas outlet. If it is not tapped in time, it will be firmly bonded to the refractory brick surface

In general, the outlet of the furnace gas will be blocked within 5-10 days, causing the pressure in the furnace to increase continuously and causing danger. Therefore, it must be cleaned up. However, the only way to clean up is to cut off the high pressure of the furnace and suspend production. Open the feeding hole on the top of the furnace, let the zinc vapor and other gases that have been reduced in the furnace be discharged from the top of the furnace, and after reducing the pressure, pull a condenser away from the furnace gas outlet along the track with a pulley

Then start cleaning. After cleaning, push the condenser to the furnace gas outlet to fix it. Such an operation is not only inconvenient but also has many potential safety hazards.

Low production efficiency, waste of resources, air pollution

[0010] 5. When the condenser tube in the condenser is condensing, the zinc powder will adhere to the wall of the condenser tube, and the condensation effect will gradually be lost. In order to clean the condenser tube, the only way to cut off the high pressure is to suspend production.

But the weak point of this patent is: the technology and equipment when this method is dealt with the zinc-containing flue gas that reduction produces in the electric furnace condenses and recovers zinc powder are very simple and have the following problems after working for a period of time:

[0012] 1. Due to the temperature difference between the smelting furnace and the furnace gas outlet, the zinc-containing flue gas is cold and agglomerated at the furnace gas outlet of the smelting furnace, resulting in blockage of the furnace gas outlet, which needs to be shut down for cleaning;

[0013] 2. The smelting furnace directly transports the zinc-containing flue gas to the condenser. The temperature of the zinc-containing flue gas is very high and the pressure is also very high, resulting in a very poor condensation effect of the zinc vapor, and a small amount of impurities and raw material powder in the furnace will directly Bringing into the condenser affects the quality of zinc powder, and zinc-containing flue gas directly enters the condenser, a little zinc vapor will be cooled very quickly, and it will directly turn into zinc lumps

[0014] 3. The temperature of the zinc powder condensed by the condenser is very high, and it cannot directly enter the vibrating screen for screening. It needs to be cooled before the vibrating screen can be sieved;

[0015] 4. When stopping production to clear the blockage of the furnace gas outlet, it is necessary to remove the condenser from the furnace gas outlet through the slide rail. At this time, the air inlet of the condenser is easy to enter the cold air and mix with the remaining zinc-containing flue gas in the condenser to cause an explosion. low security;

[0016] 5. When the production is stopped and the zinc powder adhered to the condenser tube is cleaned up, the condenser needs to be manually entered into the condenser to clean the zinc powder adhered to the condenser tube. However, after the condenser is opened, the cold air entering the condenser will The remaining zinc-containing fume mixes to cause an explosion, which not only has high labor costs, but also has low labor safety

[0017] 6. Because the zinc-containing flue gas directly enters the condenser, the condensation effect is poor, the recovery rate is low, resources are wasted, and the environment is polluted

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