CN114686700A - Fuming process of tin-containing material - Google Patents

Abstract

The invention aims to provide a fuming process of a tin-containing material of an oxygen-enriched side-blown double-zone furnace, which has obvious energy-saving effect and good environmental protection. And (3) metering the mixed materials containing tin, flux, pyrite, low-grade matte, coal granules and the like, and conveying the metered materials into a smelting area. Oxygen-enriched air is blown into the smelting zone. The generated copper matte and the slag are precipitated and separated, the copper matte is settled on the bottom layer of the hearth, and the hot slag flows into a fuming area; materials such as flux, pyrite, coal granules and the like are conveyed into the fuming zone after being metered. Oxygen-enriched air is blown into the fuming zone. And the generated copper matte is precipitated and separated from the slag, and the copper matte is settled on the bottom layer of the hearth, mixed with the copper matte in the smelting area and discharged from a siphon port. The slag is discharged through the slag hole and water is crushed. In the smelting zone and the fuming zone, the stannous oxide in the slag is mixed withThe vulcanizing agent is subjected to fuming reaction, the generated stannous sulfide is oxidized at the upper part in the furnace, and the generated stannic oxide is collected by dust collecting equipment to be used as a product. Discharging SO from the furnace₂Cooling and dedusting the high-temperature flue gas, and then sending the flue gas to prepare acid.

Description

A kind of fuming process of tin-containing material

technical field

The invention relates to a fuming process for tin-containing materials in the non-ferrous metal metallurgical industry, in particular to a fuming process for tin-containing materials using an oxygen-enriched side-blown double-zone molten pool furnace to produce tin-containing fumes and low-grade ice. Copper, flue gas sent to acid. The process slag has low tin content, low copper content, high recovery rate, energy saving, flue gas can make acid, good environmental protection effect and high degree of mobilization.

Background technique

The tin ore and tin slag are usually treated with traditional smoke furnaces, the coal consumption rate per unit material is 50-70%, and the electricity consumption per ton of material is about 300 kWh. The amount of flue gas produced by the flue gas treatment unit material is large, and the flue gas contains high SO ₂ , which requires desulfurization, and the pressure on environmental protection is high.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a fuming process for treating tin-containing materials in an oxygen-enriched side-blown double-zone furnace with high degree of automation, obvious energy-saving effect, high bed capacity and environmental protection.

The process for fuming tin-containing materials in an oxygen-enriched side-blown double-zone molten pool furnace provided by the present invention comprises the following steps:

1) Ingredients

The tin ore, tin slag and other cold materials are mixed, and the Fe:SiO ₂ of the mixture reaches 0.8 to 1.2. Materials such as pyrite, quartz sand, limestone, crushed coal, low matte copper and other cold materials are transported to the raw material warehouse by vehicles or other transportation methods, and various materials are grabbed into the batching warehouse by grab buckets for use.

After pyrite, low matte, quartz sand, limestone, crushed coal and other cold materials are measured according to the process requirements, they are transferred into the smelting area of the oxygen-enriched side-blowing double-zone furnace through the belt, and the oxygen-enriched matte smelting is carried out in the smelting area; After the pyrite, crushed coal and other cold materials are measured according to the process requirements, they are transferred into the fume zone of the oxygen-enriched side-blowing double-zone furnace through the belt transfer, and the fume smelting is carried out in the fume zone. The electronic belt scale can measure and accumulate instantaneously, and the feeding amount can be adjusted in time according to the needs of production.

2) Oxygen-enriched side blowing smelting zone:

The charge mainly includes tin-containing materials, flux, pyrite, low matte, and granular coal after being measured by a belt scale, and then transported to the oxygen-enriched side-blowing double-zone smelting zone with a belt conveyor. Oxygen-enriched air is blown from the tuyere on both sides of the smelting zone, and the blown-in oxygen-enriched air is strongly stirred to produce a bubbling layer, and the added charge is rapidly melted, and reacts strongly with fuel, reducing agent, pyrite, and low matte to form a bubbling layer. High-grade matte and slag, the tin oxide in the slag is reduced to stannous oxide, and then undergoes a fuming reaction with the vulcanizing agent to generate stannous sulfide volatilized into the flue gas, and reacts with the secondary oxygen-enriched air in the upper part of the smelting zone to generate Tin oxide and sulfur dioxide, tin oxide is collected by the dust collector along with the flue gas. The heat required for the smelting process mainly comes from the combustion heat of crushed coal and the heat of slagging reaction. The matte and slag produced by smelting are precipitated and separated in the static slag layer below the tuyere, the matte settles on the bottom of the hearth, and the slag with lower copper content is in the upper layer of the melt. The slag is discharged through the lower space of the partition wall in the double-zone furnace and flows into the fuming zone; the matte is discharged from the siphon ports on both sides or at the furnace end, and some of the matte is returned to the furnace as a vulcanizing agent, and the rest of the matte is sold as a product packaged.

The high temperature flue gas containing SO ₂ discharged from the furnace body, in which the reducing gas and the monomer sulfur are oxidized by the oxygen-enriched air blown into the furnace space, after being released from the furnace, it is cooled by the waste heat boiler, and sent to the electric precipitator after cleaning and dust removal. Sulfuric acid workshop;

3) Oxygen-enriched side blowing smoke zone: high temperature smelting slag is discharged into the smoke zone through the lower space of the partition wall in the double-zone furnace; other charge materials mainly include pyrite, granulated coal and other cold materials after being measured by belt scales, and tapes are used. The machine is transported to the upper part of the fuming zone of the oxygen-enriched side-blown double-zone furnace, and enters the furnace through the unloading hole on the top cover plate of the furnace. Oxygen-enriched air is blown from the tuyere on both sides of the furnace body in the fuming zone of the oxygen-enriched side-blowing furnace, and the blown oxygen-enriched air is strongly stirred to produce a bubbling layer, and the added charge is rapidly melted and mixed with fuel, reducing agent, pyrite A strong reaction occurs to generate lower-grade matte and slag, and the stannous oxide in the slag reacts with the vulcanizing agent to generate stannous sulfide, which volatilizes into the flue gas, and reacts with the secondary oxygen-enriched air in the upper part of the fuming zone to generate oxidation. Tin, sulfur dioxide, and tin oxide are collected by the dust collector along with the flue gas. The heat required for the smelting process mainly comes from the physical heat brought by the hot slag and the combustion heat of the broken coal. The low matte and slag produced by smelting are precipitated and separated in the static slag layer below the tuyere, the matte settles on the bottom of the hearth, and the slag with lower copper content floats on the upper layer of the melt. The low matte produced in the fuming zone and the matte produced in the smelting zone are mixed together and discharged from the siphon ports on both sides or at the furnace end. The slag releases water crushed through the slag hole in the end wall of the double-zone furnace fuming zone; the water crushed slag is stored or sold.

The high-temperature flue gas containing SO ₂ produced from the furnace body in the fuming zone, the reducing gas and monomer sulfur in it are oxidized by the oxygen-enriched air blown into the furnace space, and then mixed with the flue gas in the smelting zone through the upper part of the smelting zone After that, it is cooled by the waste heat boiler, purified and dedusted by the electric precipitator, and sent to the sulfuric acid workshop for acid production.

The technological features of the present invention are:

The invention adopts oxygen-enriched side-blown molten pool smelting double-zone furnace smoke to smelt tin-containing materials, and produces tin-containing soot, low-grade copper matte, slag and SO2 _- containing flue gas, and the flue gas is sent to acid. Among them, the oxygen-enriched side-blown molten pool smelting furnace adopts a dual-zone structure, and the middle partition wall divides the oxygen-enriched side-blown molten pool into two zones, one for smelting and one for fuming.

The fuming zone can make full use of the physical heat of the high-temperature smelting slag generated in the smelting zone, so only a small amount of coal needs to be added during fuming, the energy saving effect is very obvious, and the production cost is low. At the same time, the conventional slag discharge operation from smelting to electric furnace, electric furnace to smoke furnace is reduced, labor intensity is small, and environmental protection is good. Due to the high oxygen concentration of oxygen-enriched air in the smelting process, the bed capacity is high. The produced flue gas contains high concentration of SO ₂ , and the flue gas can make acid, which is beneficial to the recovery and utilization of sulfur in the raw material, and solves the problem of environmental pollution well.

In the smelting zone, the Fe ₃ O ₄ content in the slag is reduced by controlling the iron-silicon ratio from the raw material end by controlling the weak reducing atmosphere in the furnace. The tin content in the smelting area is relatively high. After adding pyrite and low-grade copper matte, the fuming and volatilization rate of tin is fast. By adding pyrite and low-grade matte in the smelting zone, a higher coexisting matte grade in the smelting zone is controlled. The matte produced is of high grade.

Control a strong reducing atmosphere in the fuming area, add an appropriate amount of pyrite, and the tin will continue to volatilize. The slag after fuming has low tin content and high tin recovery rate. Control the fuming zone to produce a lower coexisting matte grade, the slag after fuming has low copper content and high copper recovery rate, precious metals such as gold and silver are enriched in matte, and the precious metal recovery rate is also high.

At the same time, oxygen-enriched air is blown from the tuyere on both sides of the smelting zone and the fuming zone, and the strong agitation promotes the collision, aggregation and sedimentation of the suspended matte particles.

The main features of the technology of the present invention are described as follows:

(1) This process adopts oxygen-enriched side-blown dual-zone furnace to smoke tin-containing slag. The main features of the dual-zone furnace are as follows:

1. The middle partition wall divides the oxygen-enriched side-blown double-zone molten pool smelting furnace into a smelting zone and a smoke zone, and the height of the bottom of the partition wall is 0-350mm lower than the primary tuyere.

2. The bottom of the smelting area and the common hearth of the fuming area should be flush with the bottom, and the depth of the hearth should be 1000mm to 1400mm lower than the primary tuyere. It is not necessary to keep the bottom of the furnace too deep. The amount of copper matte stored too shallow is too small, which is inconvenient to operate.

3. A slag discharge port is set up on the copper water jacket of the front wall of the smoke zone, and the height of its center line is 450±200mm higher than that of the primary air outlet.

4. The matte siphon is released. The siphon hole can be set on the side or at the end according to the needs of the process. Multiple siphon matte holes can be opened.

5. The upper part of the two-zone furnace is connected, and the flue gas in the fuming zone passes through the upper part of the smelting zone, and enters the waste heat boiler together with the electric dust collector and then sends it to acid production.

6 The inner and outer height of the matte siphon hole is based on the 600mm matte surface in the furnace; the design size of the smelting area is 600m ³ /m ² , and the slag residence time is 1.5-2 hours for the smoke area.

(2) By controlling the ratio of the amount of coal and oxygen, the weak reducing atmosphere in the smelting area and the fuming area is controlled. The Fe ₃ O ₄ in the slag is reduced to FeO, and the SnO ₂ is reduced to SnO. The reactions (1) to (4), (17) and (18) are promoted to the right.

(3) In the smelting zone, the iron-silicon ratio of the raw material is controlled to be 0.8-1.2, and limestone is added to control the calcium-silicon ratio to be 0.15-0.3, so as to maintain better fluidity of the slag. Increasing the content of SiO ₂ in the slag is beneficial to the reduction of Fe ₃ O ₄ within a certain range. With the increase of the content of SiO ₂ in the slag, the copper content of the slag decreases continuously. Reactions (19), (20), (23) are driven to the right.

(4) Add an appropriate amount of pyrite in the smelting area to control the grade of copper matte coexisting with the slag in the smelting area, so as to promote the sulfide fuming of stannous oxide, and the sulfide of copper oxide into cuprous sulfide. At the same time, the concentration of SO ₂ in the flue gas is increased.

FeS produced by the decomposition of pyrite at high temperature promotes the reactions (5) to (16) (20) (21) (22) (23) to proceed to the right, which reduces the Fe ₃ O ₄ content in the slag and reduces the formation of the diaphragm layer. It is beneficial to the sedimentation of the inclusion matte, and makes part of the oxidized copper in the slag sulfide into the matte phase. By controlling the amount of pyrite added and the ratio of copper in the tin-containing material added, the lower grade of matte coexisting with the slag is controlled, thereby reducing the copper content of the waste slag.

(5) Add an appropriate amount of low-grade matte to the smelting area

The added low-grade matte increases the concentration of ferrous sulfide in the slag, promotes the volatilization of stannous oxide, and reacts with Fe ₃ O ₄ to form FeO, which promotes the reactions (5)～(16)(20)(21)(22)( 23) Go right. The unreacted larger-sized pyrite and matte will condense the small matte particles suspended in the slag during sedimentation, so that the sedimentation is accelerated, and the matte particles are separated from the slag. FeS is not only a vulcanizing agent, but also an excellent solvent for matte, so it can be considered that the vulcanizing agent can not only reduce the loss of copper oxide in the slag, but also reduce the number of matte particles included in the slag, and play a good role in depletion.

In addition, the copper content in the tin-containing material is low, and the amount of matte produced is relatively small. The matte temperature at the bottom of the furnace decreases after heat dissipation, which is easy to cause the matte at the bottom of the furnace to freeze and not be released. After appropriately increasing the amount of matte entering the furnace, the output of matte increases accordingly, the heat of the matte increases, the temperature decreases slowly, the matte at the bottom of the furnace is not easy to freeze, and the production is smoother.

(6) Continue to add coal and pyrite in the smoked area

The strong reducing atmosphere in the fuming zone is controlled, and pyrite is added at the same time to fumigate the tin-containing slag again, reduce the amount of tin in the slag, and improve the recovery rate of tin. The main reactions are shown in (1) to (25). Controlling the coexistence of the slag and the slag in the fuming zone is of lower matte grade. According to the equilibrium concentration of copper in the slag and the matte, following the distribution law, the copper content in the slag can be controlled to a lower level.

In addition, Pb, PbO, and PbS are volatile under high temperature conditions. In the reducing and sulfurizing atmosphere, lead is mainly volatilized in the form of lead sulfide; ZnO is reduced to metal zinc and volatilized, and is oxidized to oxidized by the secondary oxygen-enriched air in the furnace. zinc. See (24)(25) for the main reactions.

In the smelting area and the fuming area, the main chemical reactions in the sulfide fuming process of tin-containing materials are:

C+O ₂ =CO ₂ (1)

C(s)+1/2O ₂ =CO (2)

C(s)+CO ₂ =2CO (3)

CO+1/2O ₂ =CO ₂ (4)

FeS ₂ (s)=(FeS)+1/2S ₂ (5)

(FeS)+3/2O ₂ =(FeO)+O ₂ (6)

1/2S ₂ +O ₂ =SO ₂ (7)

[Sn]+1/2S ₂ =SnS(g) (8)

2(SnO)+3/2S ₂ =2SnS(g)+SO ₂ (9)

(SnO ₂ )+S ₂ =SnS(g)+SO ₂ (10)

[Sn]+(FeS)+1/2O ₂ =SnS(g)+(FeO) (11)

(SnO)+(FeS)=SnS(g)+(FeO) (12)

3(SnO ₂ )+4(FeS)=3SnS(g)+4(FeO)+SO ₂ (13)

[Sn]+SO ₂ +2CO=SnS(g)+2CO ₂ (14)

(SnO)+SO ₂ +3CO=SnS(g)+3CO ₂ (15)

(SnO ₂ )+SO ₂ +4CO=SnS(g)+4(FeO)+4CO ₂ (16)

C+Fe ₃ O ₄ =CO ₂ +FeO (17)

C+SnO ₂ =CO ₂ +SnO (18)

2FeO+SiO ₂ =2FeO·SiO ₂ (19)

3Fe ₃ O ₄ +FeS+5SiO ₂ =5(2FeO·SiO ₂ )+SO ₂ (20)

3Fe ₃ O ₄ +FeS=10FeO+SO ₂ (21)

2CuO+FeS=Cu ₂ S+FeO (22)

2FeS+2SnO+SiO ₂ =2SnS+SO ₂ +2FeO·SiO ₂ (23)

ZnO+C=Zn(g)+CO (24)

2Zn(g)+O ₂ =2ZnO (25)

Description of drawings

Fig. 1 is the process flow diagram of the present invention

Detailed ways

The technical solutions in the embodiments of the invention will be clearly and completely described below in conjunction with the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

As can be seen from Fig. 1, the technology of the present invention mainly comprises the main processes such as raw material warehouse and batching, smelting in the smelting zone of the oxygen-enriched side-blowing dual-zone furnace, and slag fuming and smelting in the fuming zone of the oxygen-enriched side-blowing dual-zone furnace, and the concrete steps are as follows:

(1) Batching of tin ore and tin slag After batching, the Fe:SiO ₂ is controlled at 0.8 to 1.2, and the processing capacity is 20t/h. The main ingredients after ingredients are as follows:

Table 1 Main components of tin-containing materials after batching

element Sn Cu Fe As S Al₂O₃ MgO SiO₂ CaO Pb Zn Element% 2.9 0.55 26 0.3 0.45 5.5 0.9 25 7.75 1.3 0.9

(2) Other basic conditions:

Smelting zone: Fe/SiO ₂ =0.95CaO/SiO ₂ =0.25 The ratio of carbon dioxide to carbon monoxide generated from the coal added is 9, the primary air oxygen concentration is 85%, the secondary air oxygen concentration is 30%, and the primary flue gas temperature is 1250 ℃, the secondary flue gas temperature is 1250℃, the matte temperature is 1150℃, and the slag temperature is 1200℃. Coal fixes 78% of carbon. Quartz sand contains 86% _SiO2 . Pyrite contains 42% iron and 38% sulfur.

(3) Through the calculation of heat balance, the main results are as follows: 1. The bill of materials to be added is (the amount of the material on a dry basis): pyrite 5t/h, quartz sand 1.23t/h, limestone 0.47t/h, coal 2.19t/h . 2 The oxygen concentration of the primary air is 85%, and the mixed gas volume is 4200 m ³ /h; the oxygen concentration of the secondary air is 30%, and the mixed gas volume is 3000 m ³ /h.

3 The main data of the output of the smelting area are as follows:

K=0.020, the flow rate of matte is: 3.47t/h, and the main components of matte are:

Table 2 The main components of matte in the smelting area

element Cu Fe S Element% 4.57 54.29 29.34

The slag flow is 24.31t/h, and the main components of the slag are:

Table 3 Main components of slag in smelting area

element Sn Cu Fe S A₂O₃ MgO SiO₂ CaO Element% 0.48 0.09 25.79 0.41 4.51 0.74 27.14 7.87

The amount of soot is 1.34t/h, and the main components of soot are:

Table 4 Main components of soot in smelting area

element Sn As S Pb Zn Element% 34.52 3.55 5.50 14.66 2.07

The main components of smoke are:

Table 5 The main components of the flue gas in the smelting area

Element SO₂ SO₃ CO₂ O₂ CO N₂ H₂O total Flow m³/h 862.97 26.69 3313.80 260.57 15.94 3000.00 2311.24 6963.47 % 8.8137 0.27 33.84 2.66 0.16 30.64 23.61 100.00

4. The bill of materials in the fuming zone is: pyrite 1.0t/h, coal 0.72t/h.

5 The oxygen concentration of the primary air in the fuming area is 60%, and the mixture volume is 1800m ³ /h; the oxygen concentration of the secondary air is 30%, and the mixture volume is 1200m ³ /h.

6 The main data of the output of the tobaccoization area are as follows:

The flow rate of matte is 0.84t/h, and the main components of matte are:

Table 6 The main components of matte in the smoked area

element Cu Fe S Element% 1.42 53.78 28.29

K=0.0148, the slag flow rate is 24.43t/h, and the main components of the slag are:

Table 7 The main components of the slag in the fumigation zone

element Sn Cu Fe S A₂O₃ MgO SiO₂ CaO Element% 0.12 0.05 25.59 0.08 4.48 0.73 28.12 8.15

The flue gas flow in the fuming area is 0.25t/h, and the main components of the fumes in the fuming area are:

Table 8 The main elements of the smoke in the fuming area

element Sn As S Pb Zn Element% 34.52 3.55 5.50 14.66 2.07

The smoke composition is:

Table 9 The main components of the flue gas in the smoking area

Element SO₂ SO₃ CO₂ O₂ CO N₂ H₂O total Flow m³/h 148.26 4.59 1046.56 187.76 7.86 1560.00 152.98 3108.00 % 4.7704 0.15 33.67 6.04 0.25 50.19 4.92 100.00

7 The amount of matte produced in the smelting zone and the fuming zone is 4.31t/h, and the main elements of the combined matte are:

Table 10 The main element composition of the combined matte

element Cu Fe S Element% 3.96 54.19 29.14

8 The combined amount of soot generated in the smelting zone and the fume zone is 1.6t/h, and the soot composition:

Table 11 The main element composition of the combined smoke and dust

element Sn As S Pb Zn Element% 34.47 3.29 5.54 13.56 3.14

9 The combined flue gas composition is:

Table 12 The main components of the combined flue gas

Element SO₂ SO₃ CO₂ O₂ CO N₂ H₂O total Flow m³/h 1011.23 31.28 4360.35 448.32 23.80 4560.00 2464.22 12899.21 % 7.84 0.24 33.80 3.48 0.18 35.35 19.10 100.00

10 Implement the main technical and economic indicators of the technology of the present invention as follows:

Low matte grade copper content 4-20% (depending on the copper content of tin-containing materials)

Slag composition: 0.05-0.3% tin, 0.05-0.2% copper

Oxygen-enriched concentration 50～90%

Bed energy rate 60～100t/(m ² .d)

Coal burning rate is about 10-20%

Flux rate 5～15%

Curing agent rate 20～35%

Oxygen unit consumption 220～260m ³ /t

Soot rate ～5% (depending on the content of tin, lead and other volatile metals in tin-containing materials)

Direct yield: Tin 93～98% Copper 92～96%

Flue gas SO ₂ concentration 6 ~ 9%

The above description of the embodiments is for the convenience of those skilled in the art to understand and use the present invention, and it is obvious that those skilled in the art can easily make various modifications to the embodiments and apply the general principles described herein. into other embodiments without creative effort. Therefore, the present invention is not limited to the above-mentioned embodiments, and improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should all fall within the protection scope of the present invention.

Claims (3)

1. The process adopts oxygen-enriched side-blown double-zone furnace fuming to smelt the tin-containing material, produces tin-containing smoke dust, low-grade matte, furnace slag and flue gas, and sends the flue gas to prepare acid.

2. An oxygen-enriched side-blown dual zone smelting furnace as claimed in claim 1, characterized in that: the middle partition wall divides the oxygen-enriched side-blown double-area molten pool smelting furnace into a smelting area and a fuming area, and the bottom of the partition wall is 0-350 mm lower than the primary air port; the bottom of the common hearth of the smelting zone and the fuming zone is flush, and the depth of the hearth is 1000-1400 mm lower than that of the primary air port; a slag discharge port is arranged on a copper water jacket on the front end wall of the fuming area, and the height of the central line of the slag discharge port is 450 +/-200 mm higher than that of the primary air port; copper matte is discharged in a siphoning way, and the siphoning hole can be arranged on the side surface or the end part according to the process requirement and can be provided with a plurality of siphoning copper matte holes; the upper parts of the double-zone furnaces are communicated, and fume in the fuming zone passes through the upper part of the smelting zone and is conveyed with the fume in the smelting zone to produce acid after passing through a waste heat boiler and electric dust collection; the internal and external heights of the copper matte siphon holes are calculated according to the 600mm of the copper matte surface in the furnace; the area of the melting zone is 600m³/m²The size is preferably designed, and the slag retention time is preferably 1.5-2 hours in the fuming area.

3. The fuming metallurgical process of claim 1, wherein: adding crushed coal, raw materials, pyrite, low-grade matte and flux in a smelting area according to the amount required by the process, improving the activity of ferrous sulfide in slag, and ensuring good fuming effect of tin, so that Fe in the slag₃O₄The content is reduced, the formation of a diaphragm layer is reduced, the sedimentation of mixed copper matte is facilitated, and part of oxidized copper in the slag is sulfurized and enters a copper matte phase; ferrous sulfide in pyrite and low-grade matte can increase the possibility that micro-fine particle matte in a slag layer is absorbed into large particles, and the sedimentation speed is higher after the matte particles become larger; controlling the smelting zone to be in a weak reducing atmosphere to remove Fe in the material₃O₄Reducing to FeO to obtain SnO in the material₂Reducing the reaction product into SnO; controlling Fe to SiO of the slag₂In the range of 0.6 to 1.0; adding coal and pyrite into the fuming zone according to the amount of technological requirements, and controlling the fuming zone to be stronger reducing gasAn atmosphere; the stannous oxide continues to be subjected to sulfuration fuming in the fuming area, so that the tin content of the waste slag is reduced; controlling the grade of the matte coexisting with the slag in the fuming area to be reduced to less than 10 percent, thereby reducing the copper content in the waste slag; discharging SO-containing gases from smelting and dilution zones₂The reducing gas and the monomer sulfur in the high-temperature flue gas are oxidized by the blown secondary oxygen-enriched air in the hearth space, cooled by a waste heat boiler, purified and dedusted by an electric dust collector, and then sent to a sulfuric acid workshop for acid production.

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