WO2021208450A1 - Zinc recovery method and device for blast furnace or shaft furnace - Google Patents

Abstract

A zinc recovery method and device for a blast furnace or a shaft furnace. The zinc recovery device comprises a flue gas extraction annular flue (1), a flue gas extraction pipe (2), a flue gas extraction duct (4), a heat exchanger (6), a flue gas return duct (11), a flue gas return annular flue (13) and a flue gas return pipe (14). By providing an annular flue in a region with a high zinc vapor pressure in a blast furnace or a shaft furnace, flue gas is extracted out of the furnace by means of a pipe, and enters a heat exchanger (6) for condensing and recovering zinc, so as to recycle metallic zinc in the blast furnace or shaft furnace. The present invention solves the problem of smooth running of smelting of a high-zinc material, makes the high-zinc material be normally used, and makes solid waste become valuable resources, achieving metallic-state recovery of valuable metallic zinc from the high-zinc material, and being able to obtain a large amount of metallic zinc.

Description

Zinc recovery method and device for blast furnace or shaft furnace Technical field

The invention belongs to the technical field of metallurgy, and particularly relates to a zinc recovery method and device for a blast furnace or a shaft furnace.

Background technique

In the process of blast furnace ironmaking, shaft furnace steelmaking or direct reduction shaft furnace smelting, zinc will be cyclically enriched in the furnace repeatedly, resulting in poor furnace conditions and affecting production efficiency.

During blast furnace smelting, there is zinc oxide or metallic zinc in the materials. Among them, zinc oxide is reduced to metallic zinc by reducing gas, and metallic zinc is vaporized at high temperature into zinc vapor. The zinc vapor rises in the furnace with the flue gas and encounters low temperature materials. It is condensed into liquid zinc or solid zinc. As the temperature of the material rises, it is vaporized into zinc vapor. This is repeated in the furnace. When the enrichment reaches a certain level, the gas permeability of the charge will be deteriorated and the normal operation of the furnace will be affected. Problems existing in blast furnace smelting for many years.

At present, a kind of shaft furnace with gas generation that uses scrap steel to make steel also has the problem of zinc enrichment. Because shaft steelmaking uses crushed scrap as raw material, the zinc content in the crushed material is high, and the gas is generated. The shaft furnace is in a reducing atmosphere. Zinc will be the same as the blast furnace in the steel-making shaft furnace. Zinc is repeatedly enriched in the furnace. When the enrichment reaches a certain level, the air permeability of the furnace will deteriorate and normal production will be affected.

At present, the treatment of zinc-containing dust in iron and steel smelting has become a problem in the industry. The usual method is to recover part of zinc oxide dust from the sintering flue gas, and part of the high zinc dust during blast furnace smelting. There is still no way to enrich the zinc vapor in the furnace. The use of high-zinc-containing raw materials causes unsatisfactory furnace conditions, often resulting in poor air permeability and stop production. Many materials with high zinc content cannot be used as a result, forming truly useless solid waste.

In steelmaking production, the converter steelmaking production process occupies a dominant position. In the converter steelmaking process, the weight ratio of scrap steel is about 15%, and some steel plants have reached 20%. With the continuous increase, the zinc content of scrap steel has increased sharply, resulting in an increase in the zinc content of converter smoke. Due to the increase in the amount of zinc and zinc oxide in the converter fume, it is difficult to deal with the converter fume. At present, in the process of converter smoke and dust treatment, many enter the blast furnace system, so the zinc load of the blast furnace is very high, which has an impact on the smelting operation and furnace age. In order not to affect the normal operation of smelting, many steel companies dare not use dust with high zinc content, causing a large amount of metallurgical dust with high zinc content to become solid waste accumulation.

There is a shortage of zinc resources in China. On the one hand, a large amount of zinc ore is imported every year, and on the other hand, a lot of zinc resources are wasted, and a lot of solid waste pollution is also caused. The present invention proposes a method for recycling metal zinc in blast furnaces and shaft furnaces, which solves the problem of processing high-zinc-containing solid waste, and can recover a large amount of metal zinc, thereby alleviating the shortage of zinc resources in China and realizing the utilization of solid waste green resources. Turn harm into profit, and turn waste into treasure.

Technical solutions

In order to solve the above problems, the present invention provides a zinc recovery method and device for a blast furnace or a shaft furnace. According to the pressure in the furnace, the conversion temperature of the physical state of zinc is different, and the enrichment zone of zinc is also different. By determining the difference in the furnace The pressure and temperature distribution of the section, and then according to the relationship curve between the vapor pressure of zinc and the temperature pressure, the zinc circulation area is predicted, and then the annular flue is set in the section of the blast furnace or shaft furnace where the zinc is gaseously enriched. The flue gas is drawn out of the furnace and enters the zinc recovery device to realize the recovery and utilization of zinc in the blast furnace or shaft furnace. Gradually reducing, it will gradually improve the air permeability of the blast furnace or shaft furnace, and prevent the repeated enrichment of zinc in the furnace from affecting the normal progress of smelting. The specific technical solutions are as follows:

A method for recovering zinc from a blast furnace or shaft furnace includes the following steps:

Step 1. Set up the annular flue:

According to the internal temperature zone and pressure distribution of the smelting furnace of iron-making blast furnace, steel-making shaft furnace or direct reduction shaft furnace, analyze the gasification area and solid zinc enrichment area of zinc in the furnace, and the zinc vapor pressure area in the smelting furnace Set up n air outlets, set up an outgoing flue gas annular lower flue 1 outside the smelting furnace, and set up n air outlets of the same number and size as the outgoing air holes of the smelting furnace on the outgoing flue gas annular flue 1. The vent hole and the vent of the flue gas ring flue 1 are connected through the flue gas pipe 2, and the flue gas pipe valve 3 is provided on the flue gas pipe 2 to adjust the flue gas flow; then, in the smelting furnace There are m lead-back vents above the lead-out air hole, and a ring flue 13 for lead-back flue gas is set outside the smelting furnace, and m air holes are set on the ring-like flue 13 The air holes of the flue gas ring flue 13 are connected by the flue gas pipe 14, and the flue gas pipe valve 15 is provided on the flue gas pipe 14 to adjust the flue gas flow; as shown in Figure 1-4 ；

Step 2. Set up U-shaped pipes and heat exchangers:

The tail end of the outgoing flue gas ring flue 1 is connected to the outgoing flue gas pipe 4, the outgoing flue gas pipe valve 5 is arranged at the inlet end of the outgoing flue gas pipe 4, and the heat exchanger 6 is arranged on the outgoing flue gas pipe 4 , The heat exchanger 6 is provided with water inlet 7 and water outlet 8 respectively. The heat exchanger 6 is provided with a zinc collecting tank 9 and a zinc outlet 10 is provided at the lower part of the zinc collecting tank 9 to draw out the flue gas pipe 4 and the inner cavity of the heat exchanger 6 The front part is connected, the return flue gas pipe 11 is connected to the end of the inner cavity of the heat exchanger 6, the return flue gas pipe 11 is provided with a return flue gas pipe valve 12, and the outlet end of the return flue gas pipe 11 is connected to the lead The air inlet of the return flue gas annular flue 13 to form a U-shaped pipe equipped with a heat exchanger; as shown in Figures 1, 4, and 6;

Step 3. Recycling of zinc:

First connect the heat exchanger 6 to the circulating cooling water, and then turn on the flue gas pipe valve 3, the flue gas pipe valve 5, the flue gas pipe valve 12 and the flue gas pipe valve 15 in turn to control the flue gas flow rate. Zinc steam enters the outgoing flue gas annular flue 1 through the outgoing flue gas pipe 2 and enters the outgoing flue gas pipe 4, and then enters the heat exchanger 6 for cooling, controlling the flow rate of circulating cooling water, and adjusting the flue gas to pass through The amount of temperature drop of the heat exchanger 6 controls the condensation temperature drop of the heat exchanger 6 in the range of 30-100°C. When the flue gas containing zinc vapor passes through the heat exchanger 6, the zinc is condensed and adsorbed on the inner surface of the heat exchanger 6, The specific selection of the temperature drop depends on the production process requirements. The large temperature drop and the fast recovery of zinc can shorten the zinc recovery time, but the larger the temperature drop, the greater the heat loss, which will affect the smelting process; after the heat exchanger 6 The remaining flue gas passes through the return flue gas pipe 11 and the return flue gas annular flue 13 in turn, and finally circulates through the return flue gas pipe 14 into the smelting furnace; after condensing sufficient amount of zinc, adjust the heat exchanger 6, the internal temperature of the heat exchanger 6 is controlled to reach 450~480℃, so that all the zinc solidified on the inner surface of the heat exchanger 6 will melt and fall into the zinc collecting tank 9 below, open the zinc outlet 10, and zinc water When there is too much dust in the flue gas and the zinc outlet 10 is blocked, turn off the flue gas pipe valve 3, the flue gas pipe valve 5, the return flue gas pipe valve 12, and the return flue gas pipe valve 15 in sequence. The flue gas in the smelting furnace flows into the pipeline. When the temperature of the zinc recovery device drops to an operable temperature, open the door of the heat exchanger 6 and directly take out the zinc collecting tank 9 to complete the recovery of zinc once;

In the step 1, the smelting furnace lead-in air hole is above the smelting furnace lead-out air hole, the air pressure at the smelting furnace lead-out air hole is greater than the air pressure at the smelting furnace lead-in air hole, and the smelting furnace lead-out air hole is connected to the smelting furnace lead air hole. The air pressure difference at the return air hole> the pressure loss of the lead flue + the pressure loss of the zinc recovery process + the pressure loss of the lead flue, the pressure difference in the furnace is used as the power, and the remaining flue gas after the recovery of zinc is sucked back into the smelting furnace;

The device used in the zinc recovery method of a blast furnace or a shaft furnace is specifically a zinc recovery device of a blast furnace or a shaft furnace. Heater 6, return flue gas pipe 11, return flue gas annular flue 13 and return flue gas pipe 14. The inner side of the pipe wall of said exhaust flue gas annular flue 1 is provided with n pores, and said exhaust flue gas The gas hole of the gas ring flue 1 is connected with a flue gas pipe 2 for communicating with the smelting furnace; the tail end of the flue gas ring flue 1 is connected to the flue gas pipe 4, which is connected to the flue gas pipe 4 A heat exchanger 6 is provided. The lower part of the heat exchanger 6 is provided with a water inlet 7, and the upper part of the heat exchanger 6 is provided with a water outlet 8; Zinc outlet 10; the exhaust end of the tail of the flue gas duct 4 is connected to the front of the inner cavity of the heat exchanger 6, and the air inlet of the flue gas duct 11 is connected to the end of the inner cavity of the heat exchanger 6, The outlet end of the return flue gas pipe 11 is connected to the air inlet of the return flue gas ring flue 13, and the inner side of the pipe wall of the smoke return ring flue 13 is provided with m air holes. The gas hole of the gas ring flue 13 is connected with a return flue gas pipe 14 for communicating with the smelting furnace; as shown in Figure 5-6;

The exhaust gas pipe 2 is provided with an exhaust gas pipe valve 3, and the return flue gas pipe 14 is provided with a return flue gas pipe valve 15;

The intake end of the exhaust gas duct 4 is provided with an exhaust gas duct valve 5, and the exhaust end of the exhaust gas duct 11 is provided with a flue gas duct valve 12;

The outlet flue gas pipeline valve 5 and the return flue gas pipeline valve 12 preferably adopt double valves or water-cooled valves, in order to prevent gas leakage;

The flue gas outgoing ring flue 1, the outgoing flue gas pipe 2, the outgoing flue gas pipe valve 3, the outgoing flue gas pipe 4, the outgoing flue gas pipe valve 5, the zinc collecting tank 9, the return flue gas pipe 11, the return The shell lining of the flue gas pipe valve 12, the flue gas loop flue 13, the flue gas pipe 14, the flue gas pipe valve 15 and the heat exchanger 6 and the contact materials of the high temperature flue gas are all high temperature resistant materials .

Beneficial effect

Compared with the prior art, the zinc recovery method and device for a blast furnace or shaft furnace of the present invention have the following beneficial effects:

1. By drawing out the zinc-containing flue gas through the heat exchanger to recover the metal zinc, the problem of the smelting furnace's non-rotation due to zinc enrichment is solved, and the resistance of the furnace is reduced, which not only solves the problem of production antegrade, but also achieves the purpose of energy saving. .

2. After the flue gas enters the furnace body of the zinc recovery device, the pressure is stabilized, the speed is reduced, and the gas is distributed, and then it contacts the heat exchanger to cool down. The zinc vapor is liquefied or condensed and adheres to the surface of the heat exchanger. Due to the limited chance of contact between the heat exchanger and the flue gas, there will be some zinc vapor and liquid zinc droplets that have not been captured by the heat exchanger and escape with the flue gas. Therefore, the flue gas after cooling and lifting the zinc is led back through a pipe. Blast furnace or shaft furnace, in order to achieve the effect of not polluting the environment and cleaning and removing zinc, the uncaptured zinc vapor is returned to the furnace and continues to circulate. There is little heat loss during the zinc extraction process, which will not affect the normal smelting, and the furnace condition will go smoothly after the zinc is recovered, which not only reduces the running resistance, realizes energy saving, but also ensures that the production can proceed smoothly.

3. The zinc-containing flue gas returns to the furnace to continue heating up the material. After the heat exchange between the flue gas and the material, the temperature is lowered. As the temperature of the flue gas continues to decrease, the saturated vapor pressure of zinc continues to decrease, continuously condenses and precipitates, and is adhered to by the charge. , As the material descends, and as the temperature of the lower part rises, it is gasified again and repeatedly enriched. Therefore, the zinc recovery device is repeatedly used in the enrichment area to remove zinc, and a large amount of zinc can be repeatedly recovered to achieve a fully closed cycle The effect of zinc.

4. The flue gas is continuously led to cool down and extract zinc. The vapor pressure of zinc in the flue gas in the furnace is getting lower and lower, and the recovery efficiency decreases. When the partial pressure of zinc drops to a certain level, the operation of the zinc recovery device is suspended and the air is returned. The power uses the pressure difference between the inlet and outlet of the flue gas of the smelting furnace to save power and energy.

5. The zinc recovery method of the present invention is different from the normal zinc production method, because most of the zinc will be enriched in the furnace, and the escape amount is limited, as long as it does not affect the smelting production, so it does not need to be completely recovered. After the zinc is enriched to a certain concentration and then recovered, the recovery efficiency can be improved and the recovery cost can be reduced.

6. When the air permeability in the smelting furnace returns to normal, the zinc removal operation is suspended, and the method of the present invention performs intermittent zinc removal operation, which can reduce heat loss and reduce operating costs.

7. In the past, zinc recovery was done by first recovering zinc oxide ash, and then performing a series of sorting reduction. The recovery production process has high energy consumption and high cost. This patent is to obtain metal zinc directly, which makes the recovery of zinc more energy-saving, environmentally friendly and efficient.

8. The traditional recovery of zinc is only after the furnace, and cannot be recovered in the furnace, which cannot solve the problem of unsatisfactory furnace conditions. The present invention recovers zinc in the furnace, which can guarantee the smelting of ironmaking in the furnace, steelmaking in shaft furnace or direct reduction shaft furnace in real time Direct.

In summary, the present invention solves the problem of smelting of high-zinc materials, enables the normal use of high-zinc materials, turns solid waste into valuable resources, and realizes the recovery of valuable metal zinc from high-zinc materials; The implementation of the patent can obtain a large amount of metallic zinc, which can alleviate the shortage of zinc resources in China.

Description of the drawings

Figure 1 is a schematic diagram of a blast furnace with a zinc recovery device;

Figure 2 is a schematic diagram of the A-A cross-sectional structure of the connection between the return flue gas ring upper flue of the zinc recovery device and the blast furnace;

Figure 3 is a schematic diagram of the B-B cross-sectional structure of the connection between the outgoing flue gas annular lower flue of the zinc recovery device and the blast furnace;

Figure 4 is a schematic structural diagram of a shaft furnace with a zinc recovery device;

Figure 5 is a schematic diagram of the device structure of a zinc recovery method for a blast furnace or a shaft furnace;

Figure 6 is a schematic diagram of the internal structure of the heat exchanger of a blast furnace or shaft furnace zinc recovery method device;

In the picture: 1-Extract flue gas annular flue, 2-Extract flue gas pipe, 3-Extract flue gas pipe valve, 4-Extract flue gas pipe, 5-Extract flue gas pipe valve, 6-heat exchanger, 7- Water inlet; 8-outlet, 9-zinc collecting tank, 10-zinc outlet, 11-return flue gas pipe, 12-return flue gas pipe valve, 13-return flue gas annular flue, 14-lead Return flue gas pipe, 15-return flue gas pipe valve.

Embodiments of the present invention

The present invention will be further described below in conjunction with specific implementation cases, but the present invention is not limited to these embodiments.

Example 1

In a steel company, a 30m³ blast furnace smelting furnace is used for the recovery and treatment of zinc-containing iron and steel dust. Because the zinc load is too large, the furnace is often shut down for cleaning due to too much blast resistance. Each time it is cleaned, several tons of zinc are cleaned out in the gaps in the furnace wall. There are also solidified zinc, which has a great influence on the life of the furnace.

A method for recovering zinc from a blast furnace or shaft furnace includes the following steps:

Step 1. Set up the annular flue:

During the overhaul of the blast furnace smelting furnace, according to the distribution area of zinc in the smelting furnace, 6 air outlets were opened in the area of 750°C in the 30m³ blast furnace, and the flue gas ring flue 1 was set outside the blast furnace. The duct 1 is provided with 6 air holes of the same number and size as the outlet air holes of the blast furnace. The outlet air holes of the blast furnace and the air holes of the flue gas ring flue 1 are connected by the flue gas pipe 2 and are on the flue gas pipe 2 A flue gas pipe valve 3 is provided to adjust the flue gas flow; then, 6 return air holes are opened 1.5 meters above the air outlet of the blast furnace, and the return flue gas ring flue 13 is set outside the blast furnace. The flue gas ring flue 13 is provided with 6 air holes of the same number and size as the smelting furnace's return air holes. The air return holes of the blast furnace and the air holes of the smoke return ring flue 13 are connected by the return flue gas pipe 14 , And on the return flue gas pipe 14 is provided with a return flue gas pipe valve 15 to adjust the flue gas flow; as shown in Figure 1-3;

Step 2. Set up U-shaped pipes and heat exchangers:

The exhaust port at the tail end of the outgoing flue gas ring flue 1 is connected to the outgoing flue gas pipe 4, the outgoing flue gas pipe valve 5 is installed at the inlet end of the outgoing flue gas pipe 4, and a heat exchanger is installed on the outgoing flue gas pipe 4 6. The heat exchanger 6 is provided with a water inlet 7 and a water outlet 8 respectively. The heat exchanger 6 is provided with a zinc collecting tank 9 and a zinc outlet 10 is provided at the lower part of the zinc collecting tank 9 to draw out the flue gas pipe 4 and the heat exchanger 6 The front part of the cavity is connected, the return flue gas pipe 11 is connected to the end of the inner cavity of the heat exchanger 6, the return flue gas pipe 11 is provided with a return flue gas pipe valve 12, and the outlet end of the return flue gas pipe 11 is connected Lead back the flue gas to the air inlet of the annular flue 13 to form a U-shaped pipe equipped with a heat exchanger; as shown in Figures 1 and 6;

Step 3. Recycling of zinc:

Low-zinc sinter is used in the early stage of the operation of the blast furnace smelting furnace, and high-zinc sinter is used when the furnace is in normal operation. The air supply resistance increases significantly after the blast furnace is running for two days, and zinc recovery starts. First, the heat exchanger 6 is connected to the circulating cooling system. Water, and then open the exhaust gas pipe valve 3, the exhaust gas pipe valve 5, the return flue gas pipe valve 12 and the return flue gas pipe valve 15 in order to control the flue gas flow rate, and the zinc vapor will lead out the flue gas along with the flue gas. Pipe 2 enters the outgoing flue gas annular flue 1, and enters the outgoing flue gas pipe 4, and then enters the heat exchanger 6 for cooling. The variable-frequency water pump is used to control the flow rate of the cooling medium water of the heat exchanger 9 and adjust the flue gas to pass through the heat exchanger 6. Control the condensation temperature drop of the heat exchanger 6 at 60℃, the cooling water enters 30℃, and the effluent 60℃; when the flue gas containing zinc steam passes through the heat exchanger 6, the zinc is condensed and absorbed in the heat exchange On the inner surface of the device 6, the other flue gas after passing through the heat exchanger 6 passes through the return flue gas pipe 11 and the return flue gas annular flue 13 in sequence, and finally circulates back into the blast furnace through the return flue gas pipe 14. The power comes from the pressure difference between the outlet air hole and the return air hole of the blast furnace; after 6 hours of operation, after condensing sufficient amount of zinc, the flue gas flow is adjusted through the outlet flue gas pipe valve 5, and adjusted to close the heat exchanger 6 The internal temperature of the heat exchanger 6 reaches 480°C, so that all the zinc solidified on the inner surface of the heat exchanger 6 melts and falls into the zinc collecting tank 9 below. The zinc outlet 10 is opened, and the zinc water flows out for continuous collection. ; Turn off the flue gas pipe valve 3, the flue gas pipe valve 5, the flue gas pipe valve 12 and the flue gas pipe valve 15 in turn to prohibit the flue gas in the blast furnace from flowing into the pipe to complete a recovery of zinc.

5.5 tons of zinc was recovered this time, and the blast furnace smelting furnace blast returned to normal after zinc removal. After 28 hours of operation, there was another difficulty in blasting. Zinc recovery was carried out again. After 4 hours of operation, 4.8 tons of zinc were recovered. After that, zinc was removed once a day, and 4.5 tons of zinc was recovered every time. In the process of zinc removal, the normal operation of the blast furnace smelting furnace has a slight impact on the capacity of blast furnace ironmaking, but the output after zinc removal is significantly higher than before zinc removal, and the average utilization factor is about 4.2. The coke ratio is 690 kg standard coal/ton iron. If zinc is taken into account, the energy consumption is 658 kg standard coal/ton iron and zinc.

The device used in the above-mentioned zinc recovery method for a blast furnace is specifically a zinc recovery device for a blast furnace. The flue gas pipe 11, the flue gas return ring 13 and the smoke return pipe 14, the inner side of the pipe wall of the smoke extraction ring flue 1 is provided with n pores, the smoke extraction ring flue 1 The gas hole is connected with a flue gas pipe 2 for communicating with the smelting furnace; the tail end of the flue gas ring flue 1 is connected with a flue gas pipe 4, and the flue gas pipe 4 is provided with a heat exchanger 6 , The lower part of the heat exchanger 6 is provided with a water inlet 7, and the upper part of the heat exchanger 6 is provided with a water outlet 8; the inside of the heat exchanger 6 is provided with a zinc collecting tank 9, and the lower part of the zinc collecting tank 9 is provided with a zinc outlet 10; The exhaust end of the exhaust gas pipe 4 is connected to the front of the inner cavity of the heat exchanger 6, and the air inlet of the exhaust gas pipe 11 is connected to the end of the inner cavity of the heat exchanger 6. The outlet end of the pipe 11 is connected to the air inlet of the return flue gas ring flue 13, and the inner side of the pipe wall of the smoke return ring flue 13 is provided with m air holes. The gas hole is connected with a return flue gas pipe 14 for communicating with the smelting furnace; as shown in Figure 5-6;

The exhaust gas pipe 2 is provided with an exhaust gas pipe valve 3, and the return flue gas pipe 14 is provided with a return flue gas pipe valve 15;

The intake end of the exhaust gas duct 4 is provided with an exhaust gas duct valve 5, and the exhaust end of the exhaust gas duct 11 is provided with a flue gas duct valve 12;

The outlet flue gas pipeline valve 5 and the return flue gas pipeline valve 12 preferably adopt double valves or water-cooled valves, in order to prevent gas leakage;

The flue gas outgoing ring flue 1, the outgoing flue gas pipe 2, the outgoing flue gas pipe valve 3, the outgoing flue gas pipe 4, the outgoing flue gas pipe valve 5, the zinc collecting tank 9, the return flue gas pipe 11, the return The shell lining of the flue gas pipe valve 12, the flue gas loop flue 13, the flue gas pipe 14, the flue gas pipe valve 15 and the heat exchanger 6 and the contact materials of the high temperature flue gas are all high temperature resistant materials .

Example 2

An iron and steel enterprise has an all-scrap steel-making shaft furnace. After the shaft furnace is equipped with a high-temperature gas producer, the gas temperature after the gas producer is higher than 1000℃, and the high-temperature gas returns to the shaft furnace to preheat the scrap steel. The flue gas in the furnace is a reducing atmosphere , The scrap steel used in the shaft furnace is all crushed material, and the zinc content is relatively high. The steel-making shaft furnace can produce 90 tons of steel per hour. It is difficult to induce air during the operation. After the furnace is shut down, it is found that the charge is blocked due to zinc enrichment.

A method for recovering zinc from a shaft furnace includes the following steps:

Step 1. Set up the annular flue:

According to the distribution area of zinc in the shaft furnace smelting furnace, 8 air outlets are opened in the area of 720 ℃ in the shaft furnace, and the flue gas ring flue 1 is set outside the shaft furnace, and the flue gas ring flue 1 is set There are 8 air holes of the same number and size as the outlet air holes of the shaft furnace. The outlet air holes of the shaft furnace and the air holes of the flue gas ring flue 1 are connected by the flue gas pipe 2, and the flue gas pipe 2 is provided Lead out the flue gas pipe valve 3 to adjust the flue gas flow; then, 8 return air holes are opened 2 meters above the outlet air holes of the shaft furnace, and the return flue gas ring flue 13 is set outside the shaft furnace. The flue gas ring flue 13 is provided with 8 air holes of the same number and size as the shaft furnace introduction and return air holes. The air introduction holes of the shaft furnace and the air holes of the smoke return ring flue 13 are connected through the return flue gas pipe 14 Connected, and a return smoke pipe valve 15 is provided on the return smoke pipe 14 to adjust the flue gas flow; as shown in Figure 4;

Step 2. Set up U-shaped pipes and heat exchangers:

The exhaust port at the tail end of the outgoing flue gas ring flue 1 is connected to the outgoing flue gas pipe 4, the outgoing flue gas pipe valve 5 is installed at the inlet end of the outgoing flue gas pipe 4, and a heat exchanger is installed on the outgoing flue gas pipe 4 6. The heat exchanger 6 is provided with a water inlet 7 and a water outlet 8 respectively. The heat exchanger 6 is provided with a zinc collecting tank 9 and a zinc outlet 10 is provided at the lower part of the zinc collecting tank 9 to draw out the flue gas pipe 4 and the heat exchanger 6 The front part of the cavity is connected, the return flue gas pipe 11 is connected to the end of the inner cavity of the heat exchanger 6, the return flue gas pipe 11 is provided with a return flue gas pipe valve 12, and the outlet end of the return flue gas pipe 11 is connected Lead the flue gas back to the air inlet of the annular flue 13 to form a U-shaped pipe equipped with a heat exchanger; as shown in Figures 4 and 6;

Step 3. Recycling of zinc:

When the induced air resistance of the smelting furnace increases significantly, zinc recovery is started. First, connect the heat exchanger 6 to the circulating cooling water, and then sequentially open the exhaust gas pipe valve 3, the exhaust gas pipe valve 5, and the return flue gas pipe valve. 12 and the return flue gas pipe valve 15 to control the flue gas flow rate. The zinc steam enters the flue gas ring flue 1 with the flue gas through the flue gas pipe 2 and enters the flue gas pipe 4, and then enters the heat exchanger 6 For cooling, use a variable-frequency water pump to control the flow rate of the cooling medium water of the heat exchanger 9, adjust the cooling rate of the flue gas through the heat exchanger 6, control the condensation temperature drop of the heat exchanger 6 at 50°C, and the cooling water enters at 30°C. The effluent is 70℃; when the flue gas containing zinc steam passes through the heat exchanger 6, the zinc is condensed and adsorbed on the inner surface of the heat exchanger 6, and the other flue gas after passing through the heat exchanger 6 passes through the flue gas pipe 11 and The flue gas is drawn back into the annular flue 13 and finally circulated into the shaft furnace through the return flue gas pipe 14. The return air power comes from the pressure difference between the outlet air hole and the return air hole of the shaft furnace; it runs for 6 hours, After condensing a sufficient amount of zinc, adjust the flue gas flow through the flue gas pipeline valve 5, and adjust it to close the circulating cooling water of the heat exchanger 6, and the internal temperature of the heat exchanger 6 reaches 450 ℃, so that it is solidified in the heat exchanger 6 All the zinc on the surface melts and falls into the zinc collecting tank 9 below. Open the zinc outlet 10 and find that there is dust blocking the zinc outlet 10. Then close the exhaust gas pipe valve 3, the exhaust flue gas pipe valve 5, and lead back in turn. The flue gas pipe valve 12 and the return flue gas pipe valve 15 prohibit the flue gas in the smelting furnace from flowing into the pipe. Finally, when the temperature of the zinc recovery device drops to an operable temperature, open the door of the heat exchanger 6 and directly take out the zinc collector Tank 9, complete one-time recovery of zinc.

4.5 tons of zinc was recovered this time, and the shaft furnace induced air was restored to normal after dezincification. After 25 hours of operation, it was difficult to induce wind again. Zinc recovery was carried out again. After 3 hours of operation, 4.1 tons of zinc were recovered. After that, zinc was removed once a day, and 4.0 tons of zinc were recovered every time. In the process of zinc removal, the normal operation of the shaft furnace smelting furnace has a slight impact on the capacity of the shaft furnace, but the output after zinc removal is significantly higher than that before the zinc removal, which has little impact on the energy consumption of the shaft furnace.

The device used in the zinc recovery method of the above-mentioned shaft furnace is specifically a zinc recovery device of the shaft furnace. The return flue gas duct 11, the return flue gas annular flue 13 and the return flue gas pipe 14. The inner side of the pipe wall of the exhaust flue gas annular flue 1 is provided with n air holes, and the exhaust flue gas annular flue The gas hole of 1 is connected with a flue gas pipe 2 for communicating with the smelting furnace; the tail end of the flue gas ring flue 1 is connected to a flue gas pipe 4, and the flue gas pipe 4 is provided with heat exchange A water inlet 7 is provided at the lower part of the heat exchanger 6 and a water outlet 8 is provided at the upper part of the heat exchanger 6; a zinc collecting tank 9 is provided inside the heat exchanger 6 and a zinc outlet 10 is provided at the lower part of the zinc collecting tank 9 The exhaust end of the exhaust gas pipe 4 is connected to the front of the inner cavity of the heat exchanger 6, and the air inlet of the return flue gas pipe 11 is connected to the end of the inner cavity of the heat exchanger 6, and the return The gas outlet end of the flue gas pipe 11 is connected to the air inlet of the return flue gas ring flue 13, and the inner side of the pipe wall of the flue gas return ring flue 13 is provided with m air holes. The gas hole of 13 is connected with the return flue gas pipe 14, which is used to communicate with the smelting furnace; as shown in Figure 5-6;

The exhaust gas pipe 2 is provided with an exhaust gas pipe valve 3, and the return flue gas pipe 14 is provided with a return flue gas pipe valve 15;

The intake end of the exhaust gas duct 4 is provided with an exhaust gas duct valve 5, and the exhaust end of the exhaust gas duct 11 is provided with a flue gas duct valve 12;

The outlet flue gas pipeline valve 5 and the return flue gas pipeline valve 12 preferably adopt double valves or water-cooled valves, in order to prevent gas leakage;

The flue gas outgoing ring flue 1, the outgoing flue gas pipe 2, the outgoing flue gas pipe valve 3, the outgoing flue gas pipe 4, the outgoing flue gas pipe valve 5, the zinc collecting tank 9, the return flue gas pipe 11, the return The shell lining of the flue gas pipe valve 12, the flue gas loop flue 13, the flue gas pipe 14, the flue gas pipe valve 15 and the heat exchanger 6 and the contact materials of the high temperature flue gas are all high temperature resistant materials .

Claims (7)

A method for recovering zinc from a blast furnace or a shaft furnace, which is characterized in that it comprises the following steps: Step 1. Set up the annular flue: According to the internal temperature zone and pressure distribution of the smelting furnace of iron-making blast furnace, steel-making shaft furnace or direct reduction shaft furnace, analyze the gasification area and solid zinc enrichment area of zinc in the furnace, and the zinc vapor pressure area in the smelting furnace Open n air outlets, set up an outgoing flue gas annular lower flue (1) outside the smelting furnace, and set up n air outlets of the same number and size as the outgoing air holes of the smelting furnace on the flue gas outgoing annular flue (1) , The air outlet of the smelting furnace and the air hole of the flue gas ring flue (1) are connected through the flue gas pipe (2), and the flue gas pipe valve (3) is provided on the flue gas pipe (2) , Adjust the flue gas flow; then, open m return air holes above the air outlet of the smelting furnace, set up the return flue gas ring flue (13) outside the smelting furnace, and set the return flue gas ring flue (13) ) Is provided with m air holes, the return air holes of the smelting furnace and the air holes of the return flue gas ring flue (13) are connected through the return flue gas pipe (14), and are connected to the return flue gas pipe (14) Equipped with a return flue gas pipe valve (15) to adjust the flue gas flow; Step 2. Set up U-shaped pipes and heat exchangers: The tail end of the outgoing flue gas ring flue (1) is connected to the outgoing flue gas pipe (4), and the outgoing flue gas pipe valve (5) is set at the inlet end of the outgoing flue gas pipe (4). A heat exchanger (6) is installed on the pipe (4), a water inlet (7) and a water outlet (8) are arranged on the upper and lower sides of the heat exchanger (6), and a zinc collecting tank (9) is arranged inside the heat exchanger (6). A zinc outlet (10) is provided at the lower part of the zinc tank (9), and the flue gas pipe (4) is connected with the front part of the inner cavity of the heat exchanger (6); the flue gas pipe (11) and the heat exchanger (6) are returned The end of the inner cavity is connected, the return flue gas pipeline (11) is provided with a return flue gas pipeline valve (12), and the outlet end of the return flue gas pipeline (11) is connected to the return flue gas ring flue (13) The air inlet to form a U-shaped pipe with a heat exchanger; Step 3. Recycling of zinc: First connect the heat exchanger (6) to the circulating cooling water, and then turn on the flue gas pipe valve (3), the flue gas pipe valve (5), the flue gas pipe valve (12) and the flue gas pipe in turn. The valve (15) controls the flow rate of the flue gas. The zinc steam enters the flue gas ring flue (1) along with the flue gas through the flue gas pipe (2), enters the flue gas pipe (4), and then enters the heat exchanger (6) Perform cooling, control the flow rate of circulating cooling water, adjust the cooling rate of flue gas passing through the heat exchanger (6), and control the condensation temperature drop of the heat exchanger (6) within the range of 30～100℃. When the flue gas passes through the heat exchanger (6), zinc is condensed and adsorbed on the inner surface of the heat exchanger (6). Other flue gas after passing through the heat exchanger (6) passes through the return flue gas pipe (11) and Return the flue gas to the annular flue (13), and finally return to the smelting furnace through the return flue gas pipe (14); after condensing a sufficient amount of zinc, adjust the circulating cooling water of the heat exchanger (6) to control the heat exchange The internal temperature of the heat exchanger (6) reaches 450~480℃, so that all the zinc solidified on the inner surface of the heat exchanger (6) melts and falls into the zinc collecting tank (9) below, opens the zinc outlet (10), and the zinc water flows out , Or when there is a lot of dust in the flue gas and the zinc outlet (10) is blocked, turn off the flue gas pipe valve (3), the flue gas pipe valve (5), the return flue gas pipe valve (12) and the return flue gas pipe in turn. The flue gas pipe valve (15) prohibits the flue gas in the smelting furnace from flowing into the pipe. When the temperature of the zinc recovery device drops to an operable temperature, open the door of the heat exchanger (6) and directly take out the zinc collecting tank (9) to complete Recycle zinc at one time. The method for recovering zinc from a blast furnace or shaft furnace according to claim 1, characterized in that, in the step 1, the smelting furnace lead-back air hole is above the smelting furnace lead-out hole, and the smelting furnace lead-out air hole is The air pressure is greater than the air pressure at the return air hole of the smelting furnace, and the air pressure difference between the air outlet of the smelting furnace and the return air hole of the smelting furnace> the pressure loss of the exit flue + the pressure loss of the zinc recovery process + the pressure loss of the return flue, use The pressure difference in the furnace is used as the driving force to suck the remaining flue gas from the recovered zinc back into the smelting furnace. The device used in the zinc recovery method of a blast furnace or a shaft furnace according to claim 1, specifically a zinc recovery device of a blast furnace or a shaft furnace, characterized in that it comprises an annular flue (1) for drawing out the flue gas, and an outgoing flue gas The pipe (2), the flue gas pipe (4), the heat exchanger (6), the flue gas pipe (11), the flue gas ring flue (13) and the flue gas pipe (14), so The inside of the pipe wall of the flue gas outgoing ring flue (1) is provided with n air holes, and the air holes of the flue gas outgoing ring flue (1) are connected with an outgoing flue gas pipe (2) for communicating with the smelting furnace; The tail end of the outgoing flue gas ring flue (1) is connected to an outgoing flue gas pipe (4), and the outgoing flue gas pipe (4) is provided with a heat exchanger (6), and the heat exchanger (6) ) The lower part is provided with a water inlet (7), and the upper part of the heat exchanger (6) is provided with a water outlet (8); the heat exchanger (6) is provided with a zinc collecting tank (9) inside, and the lower part of the zinc collecting tank (9) is provided Zinc outlet (10); the tail outlet end of the flue gas duct (4) is connected to the front of the inner cavity of the heat exchanger (6), and the air inlet of the flue gas duct (11) is led back to the heat exchanger (6) is connected to the inner cavity tail, the outlet end of the return flue gas pipe (11) is connected to the air inlet of the return flue gas annular flue (13), and the return flue gas annular flue (13) M pores are arranged on the inner side of the tube wall of ), and the pores of the flue gas return ring flue (13) are connected with a return flue gas pipe (14) for communicating with the smelting furnace. The zinc recovery device for a blast furnace or a shaft furnace according to claim 3, characterized in that the exhaust gas pipe (2) is provided with an exhaust gas pipe valve (3), and a return flue gas pipe (14) A return flue gas pipe valve (15) is provided. The zinc recovery device for a blast furnace or shaft furnace according to claim 3, characterized in that the intake end of the extraction flue gas pipeline (4) is provided with an extraction flue gas pipeline valve (5) to return flue gas The gas outlet end of the pipeline (11) is provided with a return flue gas pipeline valve (12). The zinc recovery device for a blast furnace or shaft furnace according to claim 5, characterized in that the outlet flue gas pipeline valve (5) and the return flue gas pipeline valve (12) preferably adopt double valves or water-cooled valves, in order to prevent Gas leak. A zinc recovery device for a blast furnace or shaft furnace according to claims 3-6, characterized in that the flue gas outgoing annular flue (1), flue gas outgoing pipe (2), flue gas outgoing pipe valve ( 3), the flue gas pipeline (4), the flue gas pipeline valve (5), the zinc collecting tank (9), the flue gas pipeline (11), the flue gas pipeline valve (12), the flue gas The annular flue (13), the return flue gas pipe (14), the return flue gas pipe valve (15), the shell lining of the heat exchanger (6) and the high temperature flue gas contact materials are all high temperature resistant materials.