CN114774710A

CN114774710A - Smelting process of copper concentrate

Info

Publication number: CN114774710A
Application number: CN202210274659.0A
Authority: CN
Inventors: 贺毅林
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-03-21
Filing date: 2022-03-21
Publication date: 2022-07-22

Abstract

The invention aims to provide the smelting process for treating the copper concentrate by the oxygen-enriched side-blown double-zone furnace, which has the advantages of high recovery rate, short process flow, simple material preparation and good environmental protection. And (3) metering and conveying materials such as copper concentrate, flux, granulated coal and the like to a smelting area. Oxygen-enriched air is blown into the smelting zone. Precipitating and separating matte generated by smelting and slag, and discharging the generated matte from a siphon port after the generated matte is precipitated; the hot slag is discharged through the lower space of the intermediate wall and flows into the depletion zone. Discharging SO from the furnace₂Cooling and dedusting the high-temperature flue gas, and then sending the flue gas to prepare acid. Materials such as flux, pyrite, coal granules and the like are conveyed into a dilution area after being metered. Oxygen-enriched air is blown into the depletion zone. And precipitating and separating the low-grade matte generated in the dilution area from the slag, and discharging the low-grade matte from a siphon port after the low-grade matte is mixed with the matte in the smelting area after being settled. The barren slag water is piled up or sold for sale. From poverty of povertySO-containing products of chemical zones₂The high-temperature flue gas is mixed with the flue gas in the smelting zone, cooled, dedusted and then sent to prepare acid.

Description

Smelting process of copper concentrate

Technical Field

The invention relates to a copper concentrate smelting process in the non-ferrous metal metallurgy industry, in particular to a process for producing matte by adopting an oxygen-enriched side-blown double-zone molten pool furnace smelting process for copper concentrate.

Background

Copper concentrates are usually processed by bath smelting or flash smelting, the slag is high in copper content and requires electric furnace depletion or slow cooling beneficiation to recover the copper.

Disclosure of Invention

The invention aims to provide the oxygen-enriched side-blown double-zone copper concentrate treatment process which is high in recovery rate, short in flow, high in automation degree, obvious in energy-saving effect and good in environmental protection.

The process for smelting copper concentrate by the oxygen-enriched side-blown double-zone molten pool smelting method comprises the following steps:

1) ingredients

Materials such as copper concentrate, pyrite, quartz sand, limestone, crushed coal and other cold materials are transported to a raw material warehouse by an automobile or other transportation modes, and various materials are grabbed into a proportioning bin for standby application by a grab bucket.

After copper concentrate, quartz sand, limestone, crushed coal and other cold burden are measured according to the process requirements, the copper concentrate, the quartz sand, the limestone, the crushed coal and other cold burden are transferred by a belt and added into a smelting area of an oxygen-enriched side-blown double-area furnace, and oxygen-enriched matte smelting is carried out in the smelting area; after being measured according to the technological requirements, pyrite, flux, crushed coal and other cold materials are transferred by a belt and added into a dilution zone of an oxygen-enriched side-blown double-zone furnace, and dilution smelting is carried out in the dilution zone. The electronic belt scale can be used for instantaneous metering and accumulation, and the feeding amount can be adjusted in time according to the production requirement.

2) Oxygen-enriched side-blown smelting zone:

the furnace burden mainly comprises copper concentrate, flux and coal particles, which are measured by a belt weigher and then conveyed to a smelting area of the oxygen-enriched side-blown double-area furnace by an adhesive tape machine. Blowing oxygen-enriched air from the tuyere at two sides of the smelting zone. The blown oxygen-enriched air is intensively stirred to generate a bubbling layer, the added furnace burden is quickly melted and is intensively reacted with fuel, copper concentrate and a fusing agent to generate high-grade matte and furnace slag, and the heat required in the smelting process mainly comes from sulfide oxidation reaction heat, crushed coal combustion heat and slagging reaction heat. The matte and the slag generated by smelting are precipitated and separated in a static slag layer below the tuyere, the matte is settled at the bottom layer of the hearth, and the slag with lower copper content floats on the upper layer of the melt. Slag is discharged through the lower space of the partition wall in the double-zone furnace and flows into a depletion zone; the copper matte is discharged from siphon ports at two sides or furnace end and sent to be blown.

In addition, SO-containing gas discharged from the furnace₂The reducing gas and the monomer sulfur in the high-temperature flue gas are oxidized by blown oxygen-enriched air in a hearth space, and the high-temperature flue gas is cooled by a waste heat boiler after being discharged from a furnace, purified and dedusted by an electric dust collector and sent to a sulfuric acid workshop for acid production;

3) oxygen-enriched side-blown dilution zone: high-temperature smelting slag is discharged through the lower space of the partition wall in the double-zone furnace and flows into a depletion zone; other furnace materials mainly comprise pyrite, a fusing agent, granular coal and other cold materials, are measured by a belt weigher, are conveyed to the upper part of a depletion region of the oxygen-enriched side-blown double-zone furnace by an adhesive tape machine, and enter the furnace through a feeding hole on a furnace top cover plate. Blowing oxygen-enriched air from the air ports on two sides of the body of the dilution zone. The blown oxygen-enriched air is intensively stirred to generate a bubbling layer, the added furnace burden is quickly melted and is intensively reacted with fuel, reducing agent and pyrite to generate lower-grade matte and slag. The heat required in the smelting process mainly comes from physical heat brought by hot slag and the combustion heat of crushed coal. The low copper matte generated by smelting and the slag are precipitated and separated in a static slag layer below a tuyere, the copper matte is settled at the bottom layer of a hearth, and the slag with lower copper content floats on the upper layer of the melt. The low copper matte generated in the depletion area is mixed with the copper matte generated in the smelting area and then discharged from siphon ports at two sides or the furnace end for blowing. Discharging water from slag holes at the end wall of the dilution zone to crush the slag; piling up the water slag or selling the water slag.

SO-containing gas produced from the lean zone furnace₂The reducing gas and the monomer sulfur in the high-temperature flue gas are oxidized by blown oxygen-enriched air in the hearth space, then the high-temperature flue gas is mixed with the flue gas in the smelting zone through the upper part of the smelting zone and then is cooled by a waste heat boiler, and the high-temperature flue gas is purified and dedusted by an electric dust collector and then is sent to a sulfuric acid workshop for acid production.

The process of the invention is characterized in that:

the invention adopts an oxygen-enriched side-blown double-area furnace to smelt copper concentrate to produce matte, depleted slag, smoke dust and SO-containing slag₂Flue gas, the flue gas is sent to acid making. The intermediate partition wall with a double-zone structure for smelting the oxygen-enriched side-blown molten pool in the process divides the oxygen-enriched side-blown furnace molten pool into two zones, namely a smelting zone and a depletion zone.

The invention can fully utilize the physical heat of the high-temperature smelting slag generated in the smelting zone, so that only a small amount of coal needs to be supplemented during dilution, the energy-saving effect is very obvious, and the production cost is low. Meanwhile, the conventional slag-discharging operation from smelting to a depletion electric furnace is reduced, the labor intensity is low, and the environment is protected well.

In the smelting zone, the Fe to SiO ratio in the slag is controlled₂The ratio of Fe to Fe is 0.8-1, and Fe in the slag is reduced₃O₄The content; and controlling the weak oxidizing atmosphere to obtain a higher coexistent matte grade. The grade of the produced matte is within the range of 35-55%. Controlling a stronger reducing atmosphere in a depletion region, and simultaneously adding a proper amount of pyrite to control depletionThe melting zone has a lower coexisting matte grade, depleted slag contains low copper and has a high copper recovery rate, and precious metals such as gold and silver are enriched in the matte and also have a high precious metal recovery rate. And simultaneously blowing oxygen-enriched air from air inlets at two sides of the smelting zone and the dilution zone, and strongly stirring to promote collision, aggregation and sedimentation of suspended matte particles.

The furnace burden is simple to prepare, and because oxygen concentration of oxygen-enriched air blown into the furnace burden is high in the smelting process, the produced flue gas contains SO₂The concentration is high, the flue gas can be used for preparing acid, the recycling of sulfur in the raw materials is facilitated, and the problem of environmental pollution is well solved.

The main characteristics of the process of the invention are as follows:

the process adopts an oxygen-enriched side-blown double-zone furnace to dilute the tin-containing furnace slag, and the double-zone furnace is mainly characterized in that: 1 the middle partition wall divides the oxygen-enriched side-blown double-zone molten pool smelting furnace into a smelting zone and a dilution zone, and the bottom of the partition wall is 0-350 mm lower than a primary air port.

2 the bottom of the smelting zone is flush with the bottom of the common hearth of the depletion zone. The depth of the furnace hearth is 1000 mm-1400 mm lower than the primary tuyere. The heat preservation is difficult at the bottom of the furnace, and is unnecessary; too shallow to store too little matte for convenient handling.

A slag discharge port is arranged on a copper water jacket on the front end wall of the 3 dilution zone, and the height of the central line of the slag discharge port is 450 +/-200 mm higher than that of the primary air port.

4, discharging copper matte through siphoning, wherein the siphoning hole can be arranged on the side surface or the end part of the oxygen-enriched side-blown converter according to the process requirement, and a plurality of siphoning copper matte holes can be arranged according to the process requirement.

5, the upper parts of the double-zone furnaces are communicated, and flue gas of a dilution zone passes through the upper part of a smelting zone, enters a waste heat boiler together with electric dust collection and is then sent to prepare acid.

6, calculating the internal and external heights of the copper matte siphon holes by taking the 600mm of the copper matte surface in the furnace as a basis; the area of the melting zone is 600m³/m²The size is preferably designed, and the slag retention time in the depletion region is preferably 1.5-2 hours.

Secondly, adding a proper amount of flux into the smelting zone, and controlling the iron-silicon ratio of the smelting slag to be 0.8-1.0; increase SiO in slag₂In a certain range in favor of Fe₃O₄And (4) reducing. Adding limestoneAnd controlling the calcium-silicon ratio to be 0.15-0.3 so as to keep better fluidity of the slag. The smelting zone belongs to conventional matte smelting, and in order to control the waste slag to contain copper, the smelting zone is controlled to be in a weak oxidizing atmosphere, and the iron-silicon ratio is controlled to be low. The main combustion reactions are (1) to (4), the main decomposition reactions are (5) to (8), the main oxidation reactions are (10) to (14), and the reactions (15) to (17) are mainly used for inhibiting the triiron tetroxide.

(III) adding proper amount of coal and pyrite continuously in the depletion area

The grade of the matte coexisting with the slag in the depletion area is controlled, and the lower copper content in the slag can be obtained according to the equilibrium concentration of copper in the slag and the matte and following the distribution law. Controlling a stronger reducing atmosphere to promote the reaction (15) to be carried out rightwards; FeS generated by high-temperature decomposition of pyrite promotes reactions (9), (17) and (18) to proceed to the right, so that Fe in 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 vulcanized and enters into a copper matte phase. The lower grade of matte coexisting with slag is controlled by controlling the proportion of the added pyrite amount and the added slag copper content, thereby reducing the copper content of the waste slag.

The unreacted pyrite with larger granularity coagulates the small matte particles suspended in the slag during the 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 flux of copper matte, so that the vulcanizing agent can reduce the loss of copper oxide in slag, reduce the quantity of copper matte particles in the slag and play a good dilution role.

In the smelting zone and the depletion zone, the main chemical reactions of the smelting process are as follows:

C+O₂＝CO₂ (1)

C(s)+1/2O₂＝CO (2)

C(s)+CO₂＝2CO (3)

CO+1/2O₂＝CO₂ (4)

2CuFeS₂＝Cu₂S+2FeS+1/2S₂ (5)

2CuS＝Cu2S+1/2S₂ (6)

2Cu₃FeS₃＝3Cu₂S+2FeS+1/2S₂ (7)

2CuFeS₂+5/2O₂＝Cu₂S·FeS+FeO+2SO₂ (8)

FeS₂(s)＝FeS+1/2S₂ (9)

3FeS₂+8O₂＝Fe₃O₄+6SO₂ (10)

2CuS+O₂＝Cu₂S+SO₂ (11)

3Cu₂S+3O₂＝2Cu₂O+2SO₂ (12)

FeS+3/2O₂＝FeO+O₂ (13)

1/2S₂+O₂＝SO₂ (14)

C+Fe₃O₄＝CO₂+FeO (15)

2FeO+SiO₂＝2FeO·SiO₂ (16)

3Fe₃O₄+FeS+5SiO₂＝5(2FeO·SiO₂)+SO₂ (17)

Cu₂O+FeS＝Cu₂S+FeO (18)

drawings

FIG. 1 is a process flow diagram of the present invention

Detailed description of the invention

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be obtained by a person skilled in the art without making creative efforts based on the embodiments in the present invention, belong to the protection scope of the present invention.

As can be seen from the figure 1, the process mainly comprises the main processes of raw material storage and proportioning, smelting in a smelting area of the oxygen-enriched side-blown double-area furnace, slag depleted smelting in a depleted area of the oxygen-enriched side-blown double-area furnace and the like, and comprises the following specific steps:

and (I) batching the copper concentrate, wherein the processing capacity is 50 t/h. The main components after the ingredients are as follows:

table 1 table of main components of copper concentrate of examples

Element(s)	Cu	Fe	As	S	SiO₂	CaO
							The ingredients are%	18.00	30.00	0.300	28.00	10.00	2.00

(II) other basic conditions:

a smelting zone: Fe/SiO₂＝0.95CaO/SiO₂The ratio of carbon dioxide generated by coal added is 0.25 to carbon monoxide is 9, the primary air is 85% in oxygen concentration, the secondary air is 30% in oxygen concentration, the primary flue gas temperature is 1250 ℃, the secondary flue gas temperature is 1250 ℃, the matte temperature is 1100 ℃ and the slag temperature is 1200 ℃. Coal fixed carbon 78%. The quartz sand contains SiO₂The content was 86%. The pyrite contains 42% of iron and 38% of sulfur.

(III) through heat balance calculation, the main results are as follows: 1 adding the materials (the materials are dry basis): 50t/h of copper concentrate, 7.19t/h of quartz sand, 3.38t/h of limestone and 2.14t/h of coal.

2 primary air with oxygen concentration of 85 percent and mixed gas amount of 11100m³H; the oxygen concentration of the secondary air is 30 percent, and the gas mixture amount is 10500m³/h。

3 the main data for the output of the melting zone are as follows:

k is 0.016, the matte flow rate in the smelting zone is 17.58t/h, and the main components of the matte are as follows:

TABLE 2 melting zone matte main element composition table

Element(s)	Cu	Fe	S
				The ingredients are%	49.51	23.85	24.77

The slag flow in the smelting zone is 34.55t/h, and the slag comprises the following main components:

TABLE 3 melting zone slag principal Components Table

Element(s)	Cu	Fe	S	SiO₂	CaO
						The ingredients are%	0.78	31.33	1.62	32.98	8.25

The main components and flow of the flue gas in the smelting zone are as follows:

TABLE 4 main ingredient Table of flue gas in melting zone

Composition (A)	SO₂	SO₃	CO₂	O₂	CO	N₂	H₂O	Total up to
									Flow rate m³/h	5905.69	182.65	4230.39	822.02	15.56	9960.00	5550.58	26666.88
％	22.15	0.68	15.86	3.08	0.06	37.35	20.81	100.00

4 the feed list in the depletion zone is: 2.0t/h of pyrite, 0.25t/h of quartz sand, 0.12t/h of limestone and 0.94t/h of coal.

The oxygen concentration of the primary air in the 5 depletion region is 60 percent, and the gas mixture amount is 2000m³H; the oxygen concentration of the secondary air is 30 percent, and the gas mixture amount is 1600m³/h。

The main data for the 6 depletion zone output are as follows: the flow rate of the copper matte in the depletion area is 2.8t/h, and the main components of the copper matte are as follows:

TABLE 5 list of major elements of matte in depletion region

Element(s)	Cu	Fe	S
				The ingredients are%	5.86	58.18	31.69

K is 0.056, the slag flow in the depletion area is 33.57t/h, and the slag comprises the following main components:

TABLE 6 list of principal constituents of slag in depletion region

Element(s)	Cu	Fe	S	SiO₂	CaO
						Composition%	0.33	29.95	0.16	35.24	8.81

The main components and flow of the flue gas in the dilution zone are as follows:

TABLE 7 list of main constituents of flue gas in depletion region

Composition (I)	SO₂	SO₃	CO₂	O₂	CO	N₂	H₂O	Is totaled
									Flow rate m³/h	242.17	7.49	1363.45	187.74	10.22	1920.00	274.65	4005.71
％	6.05	0.19	34.04	4.69	0.26	47.93	6.86	100.00

7, the flow rate of the matte after the melting zone and the depletion zone are combined is 20.38t/h, and the components are as follows:

TABLE 8 Table of the combined major elements of matte

Element(s)	Cu	Fe	S
				The ingredients are%	43.52	28.57	25.72

8, the combined components of the smelting zone flue gas and the dilution zone flue gas are as follows:

TABLE 9 Table of the main constituents of the flue gas after combination

Composition (I)	SO₂	SO₃	CO₂	O₂	CO	N₂	H₂O	Is totaled
									Flow rate m³/h	6147.86	190.14	5593.84	1009.76	25.77	11880.00	5825.23	30672.60
％	20.04	0.62	18.24	3.29	0.08	38.73	18.99	100.00

9 the main technical and economic indexes of the process are as follows:

the foregoing description of the embodiments is provided to facilitate an understanding and use of the invention and it will be apparent to those skilled in the art that various modifications to the embodiments and the generic principles defined herein may be applied to other embodiments without the use of inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. The process adopts an oxygen-enriched side-blown double-zone furnace to dilute and smelt copper concentrate, mainly produces matte, dilute slag, smoke dust and flue gas, and the flue gas is sent to produce 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, smoke in the fuming zone passes through the upper part of the smelting zone, and is conveyed with the smoke in the smelting zone to be made into 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 smelting 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 copper concentrate smelting process of claim 1, wherein: adding crushed coal, copper concentrate and a flux into a smelting area, and controlling Fe: SiO 2₂The ratio is 0.8-1.0, the calcium-silicon ratio is controlled to be 0.15-0.3, and the grade of matte coexisting with slag in a smelting area is controlled to be 35-55%. Adding coal, pyrite and a flux into a dilution zone, and controlling the dilution zone to be in a stronger reducing atmosphere; controlling the grade of matte coexisting with slag in a dilution area to be less than 10%, controlling the Fe content in the dilution area: SiO 2₂The ratio is 0.6 to 0.95. Mixing the flue gas of the dilution zone and the flue gas of the smelting zone, then sending the mixed flue gas to a waste heat boiler for cooling, and sending the cooled flue gas to acid production after electric dust collection.