A process for treating copper dust with oxygen-enriched side-blowing oxidation

Abstract

The present invention relates to the technical field of comprehensive utilization of metallurgical solid waste, and provides an oxygen-enriched side-blowing oxidation treatment process for copper smoke. The mixed smoke includes: side-blowing smelting boiler ash, side-blowing smelting electrostatic dust ash, bottom-blowing smelting boiler ash, bottom-blowing smelting electrostatic dust ash, side-blowing converter blowing ash and bottom-blowing converter blowing ash; the mixed smoke is directly put into the oxygen-enriched side-blowing furnace for treatment without acid leaching and desulfurization, the copper matte produced is sent to the converter blowing section of the copper smelting system, the crude lead produced is sent to the lead system for refining, the side-blowing smelting smoke is returned to the side-blowing furnace, the side-blowing smelting slag is sent to the ore dressing workshop, and the flue gas is quenched to collect arsenic before acid production. The treatment process of the present invention is simple, the comprehensive recovery efficiency of valuable metals is high, the energy consumption is low, and the treatment cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive utilization of metallurgical solid waste, in particular to an oxygen-enriched side-blowing oxidation treatment process for copper smoke. Background Art

[0002] The copper smelting process will produce copper dust such as smelting boiler ash, smelting electrostatic dust ash, converter blowing boiler ash and converter blowing electrostatic dust ash. Copper dust contains a large amount of valuable metals such as gold, silver, copper and lead, with complex chemical composition and difficult to handle. It is a typical hazardous solid waste. Traditional treatment of copper dust is divided into two categories: one is wet treatment and the other is pyrotreatment. Wet treatment generally adopts dilute sulfuric acid leaching - copper precipitation - oxidation neutralization to remove iron and arsenic or reduction precipitation of arsenic - evaporation concentration crystallization to produce zinc sulfate and other processes. Wet treatment has problems such as long process, low recovery rate and high wastewater treatment cost.

[0003] If copper smoke is directly returned to the copper smelting system, it will not only greatly increase the impurity content of the raw materials entering the furnace, deteriorate the furnace condition, reduce the processing capacity of the furnace, but also affect the quality of the final product. A method for treating copper smoke by combining wet and pyrometallurgical methods: the copper smoke is first acid-leached, the oxides in the smoke react with the acid to form metal salts, and the metal salts and sulfides in the copper smoke react with a reducing agent under a high-temperature reducing atmosphere to recover valuable metals. For example, CN 108707756 B discloses a method for comprehensively treating copper smoke with an oxygen-enriched side-blown reduction smelting furnace, wherein the acid-leached residue of the copper smoke is batched to make bricks that meet the requirements of smelting in an oxygen-enriched side-blown reduction smelting furnace, and is directly put into an oxygen-enriched side-blown reduction smelting furnace for reduction smelting to obtain primary crude lead, primary lead matte, slag and dusty flue gas; the primary lead matte obtained by reduction smelting is enriched and smelted in an oxygen-enriched side-blown reduction smelting furnace to obtain secondary crude lead, secondary lead matte, slag and dusty flue gas. On the one hand, this technology requires acid leaching before treating copper fume, and on the other hand, it requires two reduction smeltings to recover the valuable metals in the copper fume. The treatment cost is high and the process flow is complicated.

[0004] When copper dust is treated, it is generally necessary to first perform a roasting step for desulfurization or acid leaching before treatment. The existing technology has some problems: 1. The comprehensive recovery rate of valuable elements is low and the recovery cost is high; 2. The process is cumbersome and the energy consumption is high; 3. There are potential environmental hazards. Therefore, it is urgent to develop a copper dust treatment process. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a copper fume oxygen-enriched side-blowing oxidation treatment process, which has high valuable metal recovery rate, low energy consumption and short process flow.

[0006] The technical solution of the present invention is achieved as follows: a copper fume oxygen-enriched side-blowing oxidation treatment process, comprising the following process steps:

[0007] (1) Granulation: Copper dust is a mixture of side-blown smelting boiler ash, side-blown smelting electrostatic dust ash, bottom-blown smelting boiler ash, bottom-blown smelting electrostatic dust ash, side-blown converter blowing ash and bottom-blown converter blowing ash. The mixed dust is granulated by a disc granulator. The moisture content of the pellets is 8%~10%, the particle size of the pellets is 5mm~15mm, the pelletization rate is ≥85%, and the pellets fall freely from a height of 1m without breaking.

[0008] (2) Batching: The mixed smoke particles prepared in (1) are transported to the belt of the belt conveyor by a quantitative feeder, calcium sulfate slag, soda ash, borax, iron filings, quartz stone, and pyrite, and then transported to the discharge port of the oxygen-enriched side-blown furnace. The calcium sulfate slag, soda ash, borax, iron filings, and quartz stone are added in a ratio of 5-8:10-12:3-5:25-30:15-20;

[0009] (3) Oxygen-enriched side-blowing smelting: Copper dust and auxiliary materials react physically and chemically with oxygen-enriched air blown into the two sides of the side-blowing furnace at a high temperature of 1100°C to 1200°C to produce liquid slag, copper matte, crude lead and flue gas. The slag has the smallest specific gravity and the crude lead has the largest specific gravity. The side-blowing furnace is divided into three layers, namely slag, copper matte and crude lead from top to bottom, which are discharged from the slag outlet, copper matte outlet and lead slag outlet respectively. The slag is discharged continuously, and the copper matte and crude lead are discharged intermittently. The flue gas produced is sent to the sulfuric acid workshop for acid production after the waste heat is recovered by the waste heat boiler and the dust is collected by the electric precipitator. After the arsenic is collected by quenching, it is sent to the sulfuric acid workshop for acid production.

[0010] Preferably, the copper fume and auxiliary materials mainly undergo the following reactions at a high temperature of 1100°C to 1200°C:

[0011] (1) Slag-forming reaction

[0012] Under high temperature conditions, soda ash decomposes into sodium oxide and carbon dioxide. Sodium oxide reacts with quartz to form sodium silicate. Calcium sulfate slag reacts with sodium oxide to form sodium sulfate and calcium oxide. Calcium oxide reacts with quartz to form calcium silicate. Iron filings react with oxygen to form ferrous oxide or ferroferric oxide, which react with iron oxide in the smoke and quartz to form ferric silicate. The main components of slag are Na2SiO3, CaO∙SiO2, and FeO∙SiO2:

[0013] Na2CO3=Na2O+CO2

[0014] Na2O+SiO2=Na2SiO3

[0015] CaSO4+Na2O=Na2SO4+CaO

[0016] CaO+SiO2=CaO∙SiO2

[0017] 2Fe+O2=2FeO

[0018] 6FeO+O2=2Fe3O4

[0019] 2FeO+SiO2=2FeO∙SiO2

[0020] FeS+3Fe3O4+5SiO2=5(2FeO∙SiO2)+SO2

[0021] (2) Copper matte reaction

[0022] The copper oxide in the copper fume decomposes into cuprous oxide and oxygen at high temperature. Copper sulfide reacts with oxygen to form cuprous oxide and sulfur dioxide. Cuprous oxide reacts with ferrous sulfide (FeS) in pyrite to form a eutectic copper matte mainly composed of Cu2S∙FeS, and containing precious metals such as gold and silver, a small amount of other metal sulfides (such as ZnS, PbS) and trace amounts of iron oxides (FeO, Fe3O4):

[0023] 4CuO=2Cu2O+O2

[0024] CuS+O2=Cu2O+2SO2

[0025] FeS+Cu2O=FeO+Cu2S

[0026] FeS+Cu2S=Cu2S∙FeS

[0027] (3) Lead-making reaction

[0028] Lead in copper fume mainly exists in the form of lead oxide, lead sulfate and lead sulfide. At high temperature, lead sulfate reacts with lead sulfide to form lead oxide and sulfur dioxide. Some lead sulfide reacts with oxygen to form lead oxide and sulfur dioxide. Lead sulfide reacts with lead oxide to form crude lead and sulfur dioxide.

[0029] PbSO4+PbS=PbO+SO2

[0030] 2PbS+3O2=2PbO+2SO2

[0031] PbS+2PbO=3Pb+SO2

[0032] (4) Other reactions

[0033] Arsenic in copper fume mainly exists in the form of arsenate, arsenic oxide and arsenic sulfide. Arsenic trioxide enters the gas phase directly in gaseous form at high temperature. Arsenate and arsenic sulfide undergo redox reaction at high temperature to generate arsenic trioxide and sulfur dioxide. Arsenic trioxide enters the gas phase and is recovered as powdered arsenic trioxide by quenching. In the following reaction formula, Me is a metal element such as Ca, Mg, Zn, Fe, etc.:

[0034] 4As2S3+18Me3(AsO4)2=22As2O3+12SO2+54MeO

[0035] Preferably, the mixed smoke granulated by the disc granulator has a copper content of 5% to 15%, a lead content of 30% to 45%, and a sulfur content of 10% to 30%;

[0036] The oxygen enrichment concentration is 75%~85%, the copper content in the slag is ≤1.5%, and the lead content in the slag is ≤2.0%; the copper content in the copper matte is ≥40.0%, and the lead content in the copper matte is ≤3.5%; the lead content in the crude lead is ≥60.0%, and the copper content in the crude lead is ≤2.5%.

[0037] The beneficial effects of the present invention are:

[0038] The present invention provides a copper dust oxygen-enriched side-blowing oxidation treatment process, which has the following beneficial effects:

[0039] 1. Copper dust does not require acid leaching or desulfurization, and valuable metals can be directly recovered with high recovery rate;

[0040] 2. Using sulfur self-heating smelting, no need to add fuel, low energy consumption;

[0041] 3. The process flow is short, the technology is mature and reliable, energy-saving, safe, environmentally friendly, and has a high level of automation. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0043] For better understanding and implementation, a copper fume oxygen-enriched side-blowing oxidation treatment process is described in detail below:

[0044] Embodiment 1:

[0045] (1) Granulation: The copper dust is a mixture of side-blown smelting boiler ash, side-blown smelting electrostatic dust ash, bottom-blown smelting boiler ash, bottom-blown smelting electrostatic dust ash, side-blown converter blowing ash and bottom-blown converter blowing ash. The mixed dust is granulated by a disc granulator. The ball material has a moisture content of 8%, a particle size of 7 mm, a ball formation rate of 85%, and the ball material falls freely from a height of 1 m without breaking. The copper content is 8.2%, the lead content is 35.4%, and the sulfur content is 11.2%;

[0046] (2) Batching: The mixed dust particles prepared in (1) are conveyed to the belt of the belt conveyor by a quantitative feeder, calcium sulfate slag, soda ash, borax, iron filings, quartz stone, and pyrite, and then conveyed to the discharge port of the oxygen-enriched side-blown furnace. The calcium sulfate slag, soda ash, borax, iron filings, and quartz stone are added in a ratio of 5:10:3:25:15;

[0047] (3) Oxygen-enriched side-blowing smelting: Copper dust and auxiliary materials react physically and chemically with the oxygen-enriched air blown into the two sides of the side-blowing furnace at a high temperature of 1100°C to produce liquid slag, copper matte, crude lead and flue gas. The slag has the smallest specific gravity, while the crude lead has the largest specific gravity. The side-blowing furnace is divided into three layers, namely slag, copper matte and crude lead from top to bottom, which are discharged from the slag outlet, copper matte outlet and lead slag outlet respectively. The slag is discharged continuously, while copper matte and crude lead are discharged intermittently. The flue gas produced is sent to the sulfuric acid workshop for acid production after the waste heat is recovered by the waste heat boiler and the dust is collected by the electrostatic precipitator. After quenching and arsenic collection, it is sent to the sulfuric acid workshop for acid production.

[0048] Embodiment 2:

[0049] (1) Granulation: The copper dust is a mixture of side-blown smelting boiler ash, side-blown smelting electrostatic dust ash, bottom-blown smelting boiler ash, bottom-blown smelting electrostatic dust ash, side-blown converter blowing ash and bottom-blown converter blowing ash. The mixed dust is granulated by a disc granulator. The ball material has a moisture content of 10%, a particle size of 15 mm, a ball formation rate of 85%, and the ball material falls freely from a height of 1 m without breaking. The copper content is 8.3%, the lead content is 38.6%, and the sulfur content is 14.2%;

[0050] (2) Batching: The mixed smoke particles prepared in (1) are conveyed to the belt of the belt conveyor by a quantitative feeder, calcium sulfate slag, soda ash, borax, iron filings, quartz stone, and pyrite, and then conveyed to the discharge port of the oxygen-enriched side-blown furnace. The calcium sulfate slag, soda ash, borax, iron filings, and quartz stone are added in a ratio of 8:12:5:30:20;

[0051] (3) Oxygen-enriched side-blowing smelting: Copper dust and auxiliary materials react physically and chemically with the oxygen-enriched air blown into the two sides of the side-blowing furnace at a high temperature of 1200°C to produce liquid slag, copper matte, crude lead and flue gas. The slag has the smallest specific gravity, while the crude lead has the largest specific gravity. The side-blowing furnace is divided into three layers, namely slag, copper matte and crude lead from top to bottom, which are discharged from the slag outlet, copper matte outlet and lead slag outlet respectively. The slag is discharged continuously, while copper matte and crude lead are discharged intermittently. The flue gas produced is sent to the sulfuric acid workshop for acid production after the waste heat is recovered by the waste heat boiler and the dust is collected by the electric precipitator. After quenching and arsenic collection, it is sent to the sulfuric acid workshop for acid production.

[0052] Embodiment 3:

[0053] (1) Granulation: The copper dust is a mixture of side-blown smelting boiler ash, side-blown smelting electrostatic dust ash, bottom-blown smelting boiler ash, bottom-blown smelting electrostatic dust ash, side-blown converter blowing ash and bottom-blown converter blowing ash. The mixed dust is granulated by a disc granulator. The ball material has a moisture content of 9%, a particle size of 12 mm, a ball formation rate of 88%, and the ball material falls freely from a height of 1 m without breaking. The copper content is 7.9%, the lead content is 30.5%, and the sulfur content is 10.3%;

[0054] (2) Batching: The mixed smoke particles prepared in (1) are conveyed to the belt of the belt conveyor by a quantitative feeder, calcium sulfate slag, soda ash, borax, iron filings, quartz stone, and pyrite, and then conveyed to the discharge port of the oxygen-enriched side-blown furnace. The calcium sulfate slag, soda ash, borax, iron filings, and quartz stone are added in a ratio of 7:11:4:27:18;

[0055] (3) Oxygen-enriched side-blowing smelting: Copper dust and auxiliary materials react physically and chemically with the oxygen-enriched air blown into the two sides of the side-blowing furnace at a high temperature of 1150°C to produce liquid slag, copper matte, crude lead and flue gas. The slag has the smallest specific gravity, while the crude lead has the largest specific gravity. The side-blowing furnace is divided into three layers, namely slag, copper matte and crude lead from top to bottom, which are discharged from the slag outlet, copper matte outlet and lead slag outlet respectively. The slag is discharged continuously, while copper matte and crude lead are discharged intermittently. The flue gas produced is sent to the sulfuric acid workshop for acid production after recovering waste heat through the waste heat boiler and collecting dust through the electric precipitator. After being quenched to collect arsenic, it is sent to the sulfuric acid workshop for acid production.

Claims

1. A copper dust oxygen-enriched side-blowing oxidation treatment process, characterized in that The process steps include: (1) Granulation: The copper dust is a mixed dust of side-blown smelting boiler ash, side-blown smelting electric dust ash, bottom-blown smelting boiler ash, bottom-blown smelting electric dust ash, side-blown converter blowing ash and bottom-blown converter blowing ash. The mixed dust is granulated by a disc granulator. The moisture content of the pellets is 8% to 10%, the particle size of the pellets is 5mm to 15mm, the pelletization rate is ≥85%, and the pellets fall freely at a height of 1m without breaking. The mixed dust granulated by the disc granulator has a copper content of 5% to 15%, a lead content of 30% to 45%, and a sulfur content of 10% to 30%; (2) Batching: The mixed smoke particles prepared in step (1) are respectively conveyed to the belt of the belt conveyor by a quantitative feeder, calcium sulfate slag, soda ash, borax, iron filings, quartz stone, and pyrite, and then uniformly conveyed to the discharge port of the oxygen-enriched side-blown furnace, wherein the calcium sulfate slag, soda ash, borax, iron filings, and quartz stone are added in a ratio of 5-8:10-12:3-5:25-30:15-20; (3) Oxygen-enriched side-blowing smelting: Copper dust and auxiliary materials react physically and chemically with oxygen-enriched air blown into the two sides of the side-blowing furnace at a high temperature of 1100°C to 1200°C to produce liquid slag, copper matte, crude lead and flue gas. The slag has the smallest specific gravity and the crude lead has the largest specific gravity. The side-blowing furnace is divided into three layers, namely slag, copper matte and crude lead from top to bottom, which are discharged from the slag outlet, copper matte outlet and lead slag outlet respectively. The slag is discharged continuously, and the copper matte and crude lead are discharged intermittently. The flue gas produced is sent to the sulfuric acid workshop for acid production after the waste heat is recovered by the waste heat boiler and the dust is collected by the electric precipitator. After the arsenic is collected by quenching, it is sent to the sulfuric acid workshop for acid production. The copper fume and auxiliary materials mainly undergo the following reactions at a high temperature of 1100°C to 1200°C: (1) Slag formation reaction Under high temperature conditions, soda ash decomposes into sodium oxide and carbon dioxide. Sodium oxide reacts with quartz to form sodium silicate. Calcium sulfate slag reacts with sodium oxide to form sodium sulfate and calcium oxide. Calcium oxide reacts with quartz to form calcium silicate. Iron filings react with oxygen to form ferrous oxide or ferroferric oxide, which react with iron oxide in the smoke and quartz to form ferric silicate. The main components of slag are Na2SiO3, CaO·SiO2, and FeO·SiO2: Na2CO3=Na2O+CO2 Na2O+SiO2=Na2SiO3 CaSO4+Na2O=Na2SO4+CaO CaO+SiO2=CaO·SiO2 2Fe+O2=2FeO 6FeO+O2=2Fe3O4 2FeO+SiO2=2FeO·SiO2 FeS+3Fe3O4+5SiO2=5(2FeO·SiO2)+SO2 (2) Copper matte reaction The copper oxide in the copper fume decomposes into cuprous oxide and oxygen at high temperature. Copper sulfide reacts with oxygen to generate cuprous oxide and sulfur dioxide. Cuprous oxide reacts with ferrous sulfide in pyrite to form a eutectic copper matte mainly composed of Cu2S·FeS, and containing precious metals such as gold and silver, a small amount of other metal sulfides and trace amounts of iron oxides: 4CuO=2Cu2O+O2 CuS+O2=Cu2O+2SO2 FeS+Cu2O=FeO+Cu2S FeS+Cu2S=Cu2S·FeS (3) Lead-making reaction Lead in copper fume mainly exists in the form of lead oxide, lead sulfate and lead sulfide. At high temperature, lead sulfate reacts with lead sulfide to form lead oxide and sulfur dioxide. Some lead sulfide reacts with oxygen to form lead oxide and sulfur dioxide. Lead sulfide reacts with lead oxide to form crude lead and sulfur dioxide. PbSO4+PbS=PbO+SO2 2PbS+3O2=2PbO+2SO2 PbS+2PbO=3Pb+SO2 (4) Other reactions Arsenic in copper dust mainly exists in the form of arsenate, arsenic oxide and arsenic sulfide. Arsenic trioxide enters the gas phase directly in gaseous form at high temperature. Arsenate and arsenic sulfide undergo redox reaction at high temperature to generate arsenic trioxide and sulfur dioxide. Arsenic trioxide enters the gas phase and is recovered as powdered arsenic trioxide through quenching: 4As2S3+18Me3(AsO4)2=22As2O3+12SO2+54MeO.

2. The copper fume oxygen-enriched side-blowing oxidation treatment process according to claim 1, characterized in that: The oxygen-enriched air concentration is 75% to 85%, the copper content of the slag is ≤1.5%, and the lead content of the slag is ≤2.0%; the copper content of the copper matte is ≥40.0%, and the lead content of the copper matte is ≤3.5%; the lead content of the crude lead is ≥60.0%, and the copper content of the crude lead is ≤2.5%.

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