CN116103507B

CN116103507B - Cooperative treatment method for zinc concentrate and industrial sodium sulfate waste salt

Info

Publication number: CN116103507B
Application number: CN202211607018.9A
Authority: CN
Inventors: 刘维; 李琛; 彭红葵; 张力攀; 张立; 何东祥; 沈煌; 蔡汉阳; 黎奥博
Original assignee: Hunan Ruiyi Zihuan Technology Co ltd
Current assignee: Hunan Ruiyi Zihuan Technology Co ltd
Priority date: 2022-12-14
Filing date: 2022-12-14
Publication date: 2024-07-02
Anticipated expiration: 2042-12-14
Also published as: CN116103507A

Abstract

The invention relates to a cooperative treatment method of zinc concentrate and industrial sodium sulfate waste salt, which comprises the following steps: uniformly mixing zinc sulfide concentrate, industrial sodium sulfate waste salt and flux according to the mass ratio of 100:1-30:1-20, adding into an oxidation furnace, introducing oxygen-enriched air, and carrying out oxidation smelting to obtain molten high zinc slag and first flue gas rich in SO ₂; adding the molten high zinc slag and the reducing agent into a reducing furnace, introducing oxygen-enriched air, and carrying out reduction smelting to obtain pig iron, reducing slag and second flue gas rich in metal zinc steam; the addition amount of the reducing agent is 30-80wt% of the molten high zinc slag; the reduction smelting temperature is 1400-1600 ℃; the reducing atmosphere in the reducing furnace satisfies the following conditions: the molar ratio of CO to CO ₂ is 1.2-2.5:1; condensing and layering the second flue gas to obtain the metallic zinc. The invention not only effectively reduces zinc smelting cost, but also effectively eliminates industrial sodium sulfate waste salt which is difficult to dispose, and the organic matters in the waste salt are burnt out, thereby realizing harmless disposal.

Description

Cooperative treatment method for zinc concentrate and industrial sodium sulfate waste salt

Technical Field

The invention relates to a cooperative treatment method of zinc concentrate and industrial sodium sulfate waste salt, belonging to the field of metallurgy.

Background

The conventional zinc smelting technology needs to perform oxidation roasting desulfurization on zinc sulfide concentrate to obtain zinc calcine, and then performs wet leaching or pyrogenic reduction, but the process causes that the heat energy generated by the oxidation reaction of the sulfide ore cannot be fully utilized. The existing blast furnace zinc smelting technology must sinter the charged material and must use coke as a heat source and a reducing agent, so that a large amount of coal needs to be added as a reducing agent and a heat source, thereby discharging a large amount of carbon dioxide.

The Chinese patent application CN201310310891.6 discloses a flash smelting method and equipment for lead-zinc-containing materials, which comprises the steps of mixing dry powder materials containing lead and zinc in proportion, spraying the mixture and oxygen into smelting equipment from the top of a reaction tower, wherein the smelting equipment mainly comprises a reaction tower area, a reduction area and a clarification area which are communicated with each other at the bottom, the zinc-containing materials complete oxidation desulfurization reaction in the air of the reaction tower to generate high zinc slag melt with proper melting point and float in the reaction tower area, the liquid high zinc slag melt enters the reduction area, zinc in the high zinc slag melt is reduced to generate zinc steam and is collected, lead is reduced to metallic lead, precious metals such as gold, silver and the like in raw materials are captured, and the precipitate is discharged from a lead discharge port at the bottom of a molten pool. The reduced slag is discharged through a slag discharge port, and is discarded or further fuming treatment is carried out according to the content of lead and zinc. However, the method has higher requirements on the lead content in the zinc concentrate, so that high lead slag is needed to be prepared to reduce the melting point of the system, and meanwhile, the noble metal in the raw ore needs to be trapped by lead. Only suitable for treating lead and zinc mixed sulfide ores but not low-lead-zinc concentrate.

The chemical waste salt refers to byproduct crystalline salt generated in the chemical production process. The fine chemical industry such as medicine synthesis is often accompanied by the generation of a large amount of waste salt, and waste salt generated in various basic chemical pharmaceutical processes is definitely listed as dangerous waste in the national dangerous waste directory. Due to high disposal cost and insufficient disposal capacity, a large amount of waste salt is piled up in a warehouse, and the development of enterprises is severely limited. Therefore, there is a need to develop an economical and efficient waste salt treatment process. Industrial sodium sulfate waste salt is one of common chemical waste salt, mainly contains sodium sulfate, sodium chloride and organic matters, and is mainly piled up because the value of sodium sulfate is low and the value of extracting pure sodium sulfate from the industrial sodium sulfate waste salt through complex procedures is not high.

Therefore, aiming at the current situation, the invention provides the method for constructing ZnO-Na ₂O-SiO₂ -CaO-FeO low-melting-point high-zinc slag by taking low lead-containing zinc concentrate as a raw material and carrying out collaborative smelting with industrial waste salt, meanwhile, iron is taken as a metallographic phase to replace rare noble metals in zinc concentrate which are captured by lead as the metallographic phase in the traditional process, lead and zinc are volatilized together and enter smoke to be captured through a lead rain capturing system, lead volatilization can supplement lead lost in a lead liquid pool, and extra lead supplement is not needed.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a cooperative treatment method of zinc concentrate and industrial sodium sulfate waste salt so as to realize low-cost smelting of zinc and to eliminate industrial sodium sulfate waste salt which is difficult to treat.

In order to solve the technical problems, the technical scheme of the invention is as follows:

A cooperative treatment method of zinc concentrate and industrial sodium sulfate waste salt comprises the following steps:

S1, uniformly mixing zinc sulfide concentrate, industrial sodium sulfate waste salt and flux according to the mass ratio of 100:1-30:1-20, adding into an oxidation furnace, introducing oxygen-enriched air, and carrying out oxidation smelting to obtain molten high-zinc slag (oxide slag) and first flue gas rich in SO ₂;

s2, adding the molten high-zinc slag and the reducing agent into a reducing furnace, and introducing oxygen-enriched air for reduction smelting to obtain pig iron, reducing slag and second flue gas rich in metal zinc steam;

wherein the addition amount of the reducing agent is 10-50wt%, further 10-40wt%, and further 15-30wt% of molten high zinc slag; the reduction smelting temperature is 1400-1600 ℃; the reducing atmosphere in the reducing furnace satisfies the following conditions: the mole ratio of CO to CO ₂ is 0.5-2.0:1, further 1-1.5:1;

and S3, condensing the second flue gas, and layering to obtain the metal zinc.

Thus, the invention creates ZnO-Na ₂O-SiO₂ -CaO-FeO high zinc slag with low melting point and better fluidity through S1, and ensures that S in zinc sulfide concentrate and industrial sodium sulfate waste salt enters smoke, zinc is converted into ZnO and forms molten state high zinc slag with SiO ₂, feO and the like; then carrying out reduction smelting on the high zinc slag, and controlling the reduction atmosphere to enable zinc to enter the second flue gas in the form of metallic zinc steam, wherein iron is reduced to form pig iron; and further condensing and layering the second flue gas to obtain elemental metal zinc.

Further, in S1, the mass ratio of the zinc sulfide concentrate to the industrial sodium sulfate waste salt to the flux is 100:5-25:5-15, and further 100:10-20:8-12.

Further, in S1, the temperature of the oxidation smelting is 1400-1600 ℃, preferably 1450-1550 ℃.

Further, in S1, in the molten high zinc slag, the mass ratio of FeO to SiO ₂ is 0.4-1.6:1, the mass ratio of CaO to SiO ₂ is 0.4-1.4:1, and the mass ratio of ZnO to the total mass of SiO ₂, feO, caO and ZnO is 0.4-0.8:1.

Further, in S1, the flux includes quartz stone and limestone in a proportion such that a mass ratio of FeO to SiO ₂ in the molten state high zinc dross is 0.4 to 1.6:1, the mass ratio of CaO to SiO ₂ is 0.4-1.4:1, and the mass ratio of ZnO to the total mass of SiO ₂, feO, caO and ZnO is 0.4-0.8:1 is the right.

Further, in S1, the flux includes quartz stone and limestone in a proportion such that a mass ratio of FeO to SiO ₂ in the molten state high zinc dross is 0.6 to 1.4:1, the mass ratio of CaO to SiO ₂ is 0.6-1.2:1, and the mass ratio of ZnO to the total mass of SiO ₂, feO, caO and ZnO is 0.5-0.7:1 is the right.

Optionally, the flux is composed of quartz stone and limestone.

Further, in S1 and/or S2, the oxygen concentration in the oxygen-enriched air is 40 to 80vol%, preferably 60 to 70vol%.

Further, in S1, the concentration of oxygen in the flue gas at the outlet of the oxidation furnace is 0.1-3 vol%, and further 0.3-2.5vol%, so that the iron peroxidation in the marmatite can be avoided to generate ferric oxide while the complete combustion of sulfur is ensured.

The higher oxygen concentration in the oxygen-enriched air is controlled, SO that the flue gas amount is reduced, the heat taken away by the flue gas is reduced, the smelting temperature is ensured, the concentration of SO ₂ is increased, and the acid production cost is reduced. Simultaneously, the stirring action of the oxygen-enriched air on the molten pool can accelerate the reaction.

Alternatively, the first flue gas is used for the preparation of sulfuric acid.

Further, the first flue gas is treated by a waste heat boiler, a quenching tower, a dust collector and a flue gas acid making system in sequence and then discharged after reaching standards.

Further, the oxidation furnace and the reduction furnace are communicated through a chute, so that molten high zinc slag in the oxidation furnace is input into the reduction furnace through the chute. In this way, the mobility of the molten high zinc slag can be utilized to conveniently realize the transfer of the high zinc slag between the oxidation furnace and the reduction furnace.

Further, in the zinc sulfide concentrate, the Zn content is 30-55wt%, the S content is 15-35wt%, the Fe content is less than 10wt%, the Si content is less than 5wt%, the Pb content is less than 3wt%, and the Cl content is less than 0.2wt%.

Further, in the zinc sulfide concentrate, the Zn content is 35-50wt%, the S content is 20-30wt%, the Fe content is 2-8wt%, the Si content is 1-4wt%, the Pb content is 1-2wt%, and the Cl content is 0.05-0.15wt%.

Further, in the industrial sodium sulfate waste salt, the content of Na is 15-25wt%, the content of S is 10-18wt%, the content of Cl is less than 2wt%, the content of C is 2-10wt%, the content of H is 1-5wt%, the content of O is 30-50wt%, and the content of N is less than 5wt%.

Further, the reducing agent is one or more of pulverized coal, anthracite and coke.

In the invention, sodium sulfate in the added industrial sodium sulfate waste salt can be decomposed into sodium oxide and SO ₂, and the sodium oxide and other components in slag construct a ZnO-Na ₂O-SiO₂ -CaO-FeO multi-element low smelting system, thereby reducing the melting point of the system and enhancing the fluidity of slag; SO ₂ enters the flue gas, SO ₂ concentration in the first flue gas is improved, and acid production cost is reduced. In addition, the industrial sodium sulfate waste salt contains a large amount of organic matters, and can thoroughly decompose organic components through high-temperature oxidation smelting, and meanwhile, the industrial sodium sulfate waste salt has a certain heat value, and can also supplement heat for a smelting system, so that the heat requirement of oxidation smelting is ensured.

By controlling the oxidation smelting temperature to 1400-1600 ℃, the materials in the hearth can fully form a molten state, so that the high reaction rate is ensured, the fluidity of oxidized high zinc slag is improved, and the high zinc slag is convenient to flow into a reduction furnace. Meanwhile, as the zinc concentrate has higher calorific value, the smelting temperature requirement can be met under the condition of no need of adding extra fuel.

The main reactions in the oxidation smelting process are as follows:

C_nH_xO_yN_z+O₂＝CO₂+H₂O+NO_x

2ZnS+3O₂＝2ZnO+2SO₂

(Zn,Fe)S+2O₂＝ZnO+FeO+SO₂

ZnS+2O₂＝ZnO+SO₃

2ZnS+6Na₂SO₄+6SiO₂＝6Na₂SiO₃+8SO₂(g)+2ZnO

ZnO+Fe₂O₃＝ZnFe₂O₄

2ZnO+SiO₂＝Zn₂SiO₄

CaO+Fe₂O₃＝CaO*Fe₂O₃

CaO+SiO₂＝CaO·SiO₂

In the reduction smelting process, the reducing atmosphere in the reducing furnace is controlled to be CO/CO ₂ =0.5-2.0, and zinc and iron oxides can be fully reduced.

Optionally, the second flue gas is input into a lead rain condensing system, heat exchange is carried out on the second flue gas and then the temperature is reduced to 550 ℃, zinc vapor is condensed into zinc liquid, the zinc liquid is captured into the lead liquid, a product zinc ingot is obtained through precipitation and layering, and the residual flue gas is purified by flue gas purification procedures such as a surface cooler, a cloth bag dust collector and the like to obtain clean gas.

Optionally, water quenching is carried out on the reducing slag to obtain water quenched slag.

Part of the reaction in the reduction smelting process is as follows:

2C+O₂＝2CO

ZnFe₂O₄+2C＝Zn(g)+2FeO+CO(g)

Zn₂SiO₄+2C＝2Zn(g)+SiO₂+2CO(g)

*2FeO*SiO₂+CaO＝2FeO+CaSiO₃

*2FeO*SiO₂+Na₂O＝2FeO+Na₂SiO₃

ZnO+CO＝Zn+CO₂

Fe₂O₃+CO＝2FeO+CO₂

FeO+CO＝Fe+CO₂

2CaO*Fe₂O₃+3C＝2CaO+3CO₂(g)+2Fe

Zn₂SiO₄+CaO+2C＝2Zn+CaSiO₃+2CO(g)

CaO+SiO₂＝CaO·SiO₂

Fe+C＝Fe₃C

the invention adopts industrial sodium sulfate waste salt to construct a multi-element smelting system, reduces the melting point of high zinc slag, can directly treat low lead-zinc concentrate, and simultaneously captures noble metals such as gold, silver and the like by iron, thereby having higher economic benefit.

Compared with the prior art, the invention has the following beneficial effects:

(1) According to the invention, through the cooperative treatment of the industrial sodium sulfate waste salt and the zinc concentrate, not only is the redundant heat in the oxidation smelting effectively utilized, the energy conservation and consumption reduction are facilitated, the zinc smelting cost is reduced, but also the industrial sodium sulfate waste salt which is difficult to dispose is effectively consumed, the organic matters in the industrial sodium sulfate waste salt are completely burnt, and the harmless disposal is realized. Meanwhile, the active ingredients in the industrial sodium sulfate waste salt are utilized to construct a ZnO-Na ₂O-SiO₂ -CaO-FeO multi-element smelting system, so that the melting point of high zinc slag is reduced, and continuous smelting is possible; in addition, S element in the industrial sodium sulfate waste salt is converted into sulfur dioxide to participate in acid production, and the recycling utilization is also obtained.

(2) According to the invention, continuous oxygen-enriched smelting is carried out on zinc concentrate, the heat in the whole system is basically from the high heat value of the zinc sulfide concentrate, and the added reducing agent only needs to play a role in reduction, and does not need to be used for additional heat supply, so that the purposes of energy conservation and carbon reduction are achieved.

(3) Compared with the conventional process, the treatment method fully utilizes the heat value in the zinc concentrate and the effective components in the industrial sodium sulfate waste salt, and generates pig iron and zinc ingots by one step of continuous smelting, thereby greatly reducing the energy consumption, shortening the process flow and being beneficial to improving the treatment efficiency.

(4) Compared with the conventional process, the treatment method fully utilizes the capability of capturing rare noble metals by iron, replaces the conventional process and adopts copper sulfur or lead as metallographic capturing rare noble metals. The treatment method provided by the invention has the advantages of strong trapping capacity and extremely high universality, and provides a method for enriching rare noble metals in lead-free and copper-free materials.

(5) The invention replaces the traditional zinc concentrate pyrogenic process treatment process and adopts a lead-zinc combined smelting mode, replaces the traditional PbO-ZnO-SiO2-CaO slag type by constructing a low-melting point ZnO-Na ₂O-SiO₂ -CaO-FeO slag type, replaces lead with iron, and recovers rare noble metals, thereby being applicable to the treatment of lead-zinc mixed ores, zinc concentrates, high-iron zinc concentrates and the like.

Drawings

FIG. 1 is a flow chart of a co-processing method of the present invention.

Detailed Description

The present invention will be described in detail with reference to examples. It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other. The relevant percentages refer to mass percentages unless otherwise indicated.

Example 1

The cooperative treatment method of zinc concentrate and industrial sodium sulfate waste salt of the embodiment comprises the following steps:

S1, uniformly mixing zinc sulfide concentrate, industrial sodium sulfate waste salt, quartz stone and limestone according to the mass ratio of 100:15:3:6, adding the mixture into an oxidation furnace, introducing oxygen-enriched air with the oxygen concentration of 80vol% for oxidation smelting, and obtaining molten high zinc slag and first flue gas with the SO ₂ concentration of 55vol% and the O ₂ concentration of 0.5 vol%;

Wherein the temperature of the oxidation smelting is 1500 ℃; the main chemical compositions of zinc sulfide concentrate and industrial sodium sulfate waste salt are shown in tables 1 and 2 respectively. In the molten state high zinc slag, the mass ratio of FeO to SiO ₂ is 1.2:1, a mass ratio of CaO to SiO ₂ of 0.8:1, a mass ratio of ZnO to a total mass of SiO ₂, feO, caO and ZnO of 0.6:1.

TABLE 1 main chemical composition of Zinc sulfide concentrate

Element(s)	Zn	Fe	Si	S	H2O	Pb	Cl
								Content/wt%	48.2	8.8	2.3	23.2	8.3	3.6	0.1

TABLE 2 main chemical composition of industrial sodium sulfate waste salt

Element(s)	Na	S	Cl	C	H	O	N
								Content/wt%	24.5	18.1	1.2	6.4	3.2	42.3	3.2

S2, inputting molten high-zinc slag in an oxidation furnace into a reduction furnace through a chute, adding a reducing agent into the reduction furnace, and introducing oxygen-enriched air with the oxygen concentration of 80vol% for reduction smelting to obtain pig iron, reduction slag and second flue gas rich in metal zinc steam;

Wherein the addition amount of the reducing agent is 20wt% of the molten high zinc slag; the reduction smelting temperature is 1450 ℃; the reducing atmosphere in the reducing furnace satisfies the following conditions: the molar ratio of CO to CO ₂ is 1.2:1; the reducing agent is anthracite.

S3, condensing the second flue gas, layering, and obtaining metal zinc;

And carrying out water quenching on the reducing slag to obtain water quenching slag.

Through detection, the obtained pig iron contains 95wt% of iron and 4.5wt% of carbon, the iron recovery rate reaches 96wt%, and the trapping rates of rare noble metals such as tin, bismuth, antimony, gold, silver and the like are 95%, 98%, 97%, 99% and 99% respectively. The zinc content in the metallic zinc is 98.9wt percent, and the zinc recovery rate reaches 99wt percent. The zinc content in the water quenching slag is 0.4wt% and the iron content is 1.2wt%.

Example 2

S1, uniformly mixing zinc sulfide concentrate, industrial sodium sulfate waste salt, quartz stone and limestone according to the mass ratio of 100:10:2:3, adding the mixture into an oxidation furnace, and introducing oxygen-enriched air with the oxygen concentration of 80vol% for oxidation smelting to obtain molten high zinc slag and first flue gas with the SO ₂ concentration of 60vol% and the O ₂ concentration of 1.2 vol%;

Wherein the temperature of the oxidation smelting is 1550 ℃; the main chemical compositions of zinc sulfide concentrate and industrial sodium sulfate waste salt are shown in tables 3 and 4 respectively. In the molten state high zinc slag, the mass ratio of FeO to SiO ₂ is 1.2:1, a mass ratio of CaO to SiO ₂ of 0.6:1, and a mass ratio of ZnO to a total mass of SiO ₂, feO, caO and ZnO of 0.7:1.

TABLE 3 principal chemical composition of Zinc sulfide concentrate

Element(s)	Zn	Fe	Si	S	H₂O	Pb	Cl
								Content/wt%	51	5.7	3.4	28.2	5.8	4.3	0

TABLE 4 main chemical composition of industrial sodium sulfate waste salt

Element(s)	Na	S	Cl	C	H	O	N
								Content/wt%	17.8	19.8	1.2	4.2	2.5	48.2	2.4

Wherein the addition amount of the reducing agent is 18wt% of the molten high zinc slag; the reduction smelting temperature is 1500 ℃; the reducing atmosphere in the reducing furnace satisfies the following conditions: the molar ratio of CO to CO ₂ is 1.4:1; the reducing agent is anthracite.

S3, condensing the second flue gas, layering, and obtaining metal zinc;

Through detection, the obtained pig iron contains 96wt% of iron and 3.2wt% of carbon, the iron recovery rate reaches 96wt%, and the rare noble metal trapping rates of tin, bismuth, antimony, gold, silver and the like are 93%, 97%, 95%, 99% and 99% respectively. The zinc content in the metal zinc is 99.2wt%, and the zinc recovery rate reaches 99wt%. The zinc content in the water quenching slag is 0.3wt% and the iron content is 1.3wt%.

Comparative example 1

Example 1 was repeated, with the only difference that: no industrial sodium sulfate waste salt is added.

Through detection, materials in the oxidation furnace cannot be melted, slag is difficult to transfer into the reduction furnace, the reaction process is unstable in temperature and incomplete in reaction, the concentration of SO ₂ in flue gas fluctuates greatly, and acid cannot be produced. After 10% of industrial waste salt is added into the furnace, the slag is obviously improved and smoothly discharged into the reduction furnace.

Comparative example 2

Example 1 was repeated, with the only difference that: the adding amount of industrial sodium sulfate waste salt is 1% of the mass of zinc sulfide concentrate.

Through detection, the materials in the oxidation furnace are difficult to melt, and the sintering of the materials is obvious. After 10% of industrial waste salt is added into the furnace, the slag is obviously improved and smoothly discharged into the reduction furnace.

Comparative example 3

Example 1 was repeated, with the only difference that: the addition amount of the industrial sodium sulfate waste salt is 5 percent of the mass of the zinc sulfide concentrate.

Through detection, the materials in the oxidation furnace are completely melted, but the viscosity is higher, the fluidity of slag is poorer, and the slag can still be smoothly discharged into the reduction furnace. The smelting effect in the reduction furnace is good, the obtained pig iron contains 92wt% of iron, 2.8wt% of carbon, the iron recovery rate reaches 88wt%, and the capture rates of rare noble metals such as tin, bismuth, antimony, gold, silver and the like are 89%, 91%, 88%, 92% and 90%, respectively. The zinc content in the metal zinc is 99.5wt%, and the zinc recovery rate reaches 99wt%. The zinc content in the water quenching slag is 0.4wt% and the iron content is 2.3wt%.

Example 3

Example 1 was repeated, with the only difference that: the addition amount of the industrial sodium sulfate waste salt is 25% of the mass of the zinc sulfide concentrate.

Through detection, the materials in the oxidation furnace are completely melted, the fluidity is good, the flue gas condition is stable, and the materials can be smoothly discharged into the reduction furnace. However, this slag type causes corrosion of the refractory bricks in the reduction furnace to some extent, and the temperature in the reduction furnace is difficult to increase, resulting in a decrease in iron recovery rate. The obtained pig iron contains 93wt% of iron and 3.6wt% of carbon, the iron recovery rate reaches 85wt%, and the trapping rates of rare noble metals such as tin, bismuth, antimony, gold, silver and the like are 88%, 82%, 81%, 90% and 89% respectively. The zinc content in the metal zinc is 99.3wt%, and the zinc recovery rate reaches 95wt%. The zinc content in the water quenching slag is 5.3wt% and the iron content is 2.8wt%.

Comparative example 4

Example 1 was repeated, with the only difference that: the addition amount of the industrial sodium sulfate waste salt is 38% of the mass of the zinc sulfide concentrate.

Through detection, the materials in the oxidation furnace are completely melted, the fluidity is good, the flue gas condition is stable, and the materials can be smoothly discharged into the reduction furnace. However, the slag type re-reduction furnace is internally smelted to cause serious corrosion of refractory bricks, and the temperature of slag is difficult to rise to cause difficult generation of molten iron. After adding a large amount of quartz stone, the conditions are improved.

Comparative example 5

Example 2 was repeated, with the only difference that: and controlling the oxygen concentration of the flue gas at the outlet of the oxidizing furnace in the step S1 to be 0%.

Through detection, sulfur in the slag is not completely removed, and partial mixed slag of the iron sulfide metallographic phase and the high zinc slag exists in the discharged slag. Smelting in a reducing furnace to obtain pig iron with iron content of 87wt%, carbon content of 2.1wt%, iron recovery rate of 94wt% and trapping rates of 97%, 98%, 99% and 99% of rare noble metals such as tin, bismuth, antimony, gold, silver, etc. The zinc content in the metal zinc is 99.3wt%, and the zinc recovery rate reaches 99wt%. The zinc content in the water quenching slag is 0.2wt% and the iron content is 1.3wt%. However, the sulfur content of the pig iron is 4.5%, which cannot meet the standard of pig iron for casting, and further desulfurization is required.

Example 4

Example 2 was repeated, with the only difference that: the oxygen concentration of the flue gas at the outlet of the oxidizing furnace in the step S1 is controlled to be 0.1vol percent.

Through detection, sulfur in slag is almost removed, the viscosity of slag is still good, the fluidity is good, and the concentration of SO ₂ in flue gas is stable. Smelting in a reducing furnace to obtain pig iron with iron content of 94wt%, carbon content of 3.1wt%, iron recovery rate of 97wt% and trapping rates of rare noble metals such as tin, bismuth, antimony, gold, silver and the like of 95%, 94%, 96%, 98% and 99% respectively. The zinc content in the metal zinc is 99.6wt%, and the zinc recovery rate reaches 99wt%. The zinc content in the water quenching slag is 0.4wt% and the iron content is 1.0wt%.

Example 5

Example 2 was repeated, with the only difference that: the oxygen concentration of the flue gas at the outlet of the oxidizing furnace in the step S1 is controlled to be 3vol percent.

Through detection, sulfur in slag is almost removed, slag fluidity is poor, and SO ₂ concentration in flue gas is stable. Smelting in a reducing furnace to obtain pig iron with iron content of 94wt%, carbon content of 3.1wt%, iron recovery rate of 97wt% and trapping rates of rare noble metals such as tin, bismuth, antimony, gold, silver and the like of 95%, 94%, 96%, 98% and 99% respectively. The zinc content in the metal zinc is 99.6wt%, and the zinc recovery rate reaches 99wt%. The zinc content in the water quenching slag is 0.4wt% and the iron content is 1.0wt%.

Comparative example 6

Example 2 was repeated, with the only difference that: and controlling the oxygen concentration of the flue gas at the outlet of the oxidizing furnace in the step S1 to be 5vol%.

Through detection, sulfur in the slag is almost removed, but the viscosity of the slag is too high, so that the slag is difficult to smoothly discharge into the next stage of process. After a certain amount of reduced coal is fed, the furnace condition is improved.

Comparative example 7

Example 2 was repeated, with the only difference that: the reducing atmosphere in the reducing furnace is controlled to satisfy the following conditions: the molar ratio of CO to CO ₂ was 0.2:1.

As a result, it was found that iron carburization was insufficient in the reduction furnace, iron was incompletely reduced into the molten iron, and the direct iron yield was reduced to 78.4%. And the direct yield of zinc is reduced to 84.3%, and a large amount of zinc oxide scum is generated in the lead liquid pool, which indicates that zinc is greatly oxidized in the condensation process.

Example 6

Example 2 was repeated, with the only difference that: the reducing atmosphere in the reducing furnace is controlled to satisfy the following conditions: the molar ratio of CO to CO ₂ was 0.5:1.

The obtained pig iron contains 95wt% of iron and 2.1wt% of carbon, the iron recovery rate reaches 87wt%, and the trapping rates of rare noble metals such as tin, bismuth, antimony, gold, silver and the like are 82%, 83%, 86%, 79% and 89%, respectively. The zinc content in the metallic zinc is 99.6wt percent, and the direct zinc yield is 89wt percent. The zinc content in the water quenching slag is 1.2wt% and the iron content is 3.2wt%. The recovery rate of iron and the direct recovery rate of zinc are all reduced due to the weak reducing atmosphere.

Example 7

Example 2 was repeated, with the only difference that: the reducing atmosphere in the reducing furnace is controlled to satisfy the following conditions: the molar ratio of CO to CO ₂ was 2.0:1.

The obtained pig iron contains 92wt% of iron and 4.2wt% of carbon, the iron recovery rate reaches 97wt%, and the trapping rates of rare noble metals such as tin, bismuth, antimony, gold, silver and the like are 92%, 95%, 96%, 99% and 99% respectively. The zinc content in the metallic zinc is 99.2wt percent, and the zinc direct yield is 92wt percent. The zinc content in the water quenching slag is 0.2wt% and the iron content is 0.7wt%. The working condition is not changed greatly, but the coal consumption is obviously increased, and the carbon content of pig iron is obviously increased.

Comparative example 8

Example 2 was repeated, with the only difference that: the reducing atmosphere in the reducing furnace is controlled to satisfy the following conditions: the molar ratio of CO to CO ₂ was 2.5:1.

The experimental conditions and the above examples are not changed greatly, but the coal consumption is obviously increased, and the CO concentration is too high at the moment, so that no obvious further benefit is generated, and the method is not suitable for further improving the CO concentration.

Comparative example 9

Example 1 was repeated, with the only difference that: the ratio of the mass of ZnO to the total mass of SiO ₂, feO, caO and ZnO was 0.3:1.

Through detection, the production index of the condition is not changed greatly, but the energy consumption of zinc and iron is obviously increased, and the method has no economic benefit basically, and is not suitable for treatment by adopting the method.

Example 8

Example 1 was repeated, with the only difference that: the ratio of the mass of ZnO to the total mass of SiO ₂, feO, caO and ZnO was 0.4:1.

Through detection, the production index change is not large under the condition, the energy consumption per ton of zinc and iron is higher, and the economic value is lower.

Example 9

Example 1 was repeated, with the only difference that: the ratio of the mass of ZnO to the total mass of SiO ₂, feO, caO and ZnO was 0.8:1.

Through detection, the production index is good in the condition, the energy consumption of zinc and iron is low, but the viscosity of slag in an oxidation furnace is high, and the zinc oxide proportion is not suitable to be further improved.

Comparative example 10

Example 1 was repeated, with the only difference that: the ratio of the mass of ZnO to the total mass of SiO ₂, feO, caO and ZnO was 0.9:1.

Through detection, the viscosity of the oxidized slag is too high, the oxidized slag cannot be smoothly discharged into a reduction furnace, and the furnace condition is normal by adding a certain amount of SiO ₂.

The foregoing examples are set forth in order to provide a more thorough description of the present application and are not intended to limit the scope of the application, and various modifications of the application, which are equivalent to those skilled in the art upon reading the present application, will fall within the scope of the application as defined in the appended claims.

Claims

1. A cooperative treatment method of zinc concentrate and industrial sodium sulfate waste salt is characterized by comprising the following steps:

S1, uniformly mixing zinc sulfide concentrate, industrial sodium sulfate waste salt and flux according to the mass ratio of 100:5-30:1-20, adding into an oxidation furnace, introducing oxygen-enriched air, and carrying out oxidation smelting to obtain molten high zinc slag and first flue gas rich in SO ₂; in the molten state high zinc slag, the mass ratio of FeO to SiO ₂ is 0.4-1.6:1, the mass ratio of CaO to SiO ₂ is 0.4-1.4:1, and the mass ratio of ZnO to the total mass of SiO ₂, feO, caO and ZnO is 0.4-0.8: 1, a step of; the concentration of oxygen in the flue gas at the outlet of the oxidation furnace is 0.1-3vol%;

Wherein the addition amount of the reducing agent is 10-50wt% of the molten high zinc slag; the reduction smelting temperature is 1400-1600 ℃; the reducing atmosphere in the reducing furnace satisfies the following conditions: the mole ratio of CO to CO ₂ is 0.5-2.0:1, a step of;

and S3, condensing the second flue gas, and layering to obtain the metal zinc.

2. The cooperative processing method according to claim 1, wherein in S1, the temperature of the oxidation smelting is 1400-1600 ℃.

3. The co-processing method according to claim 2, wherein the temperature of the oxidative smelting is 1450-1550 ℃.

4. The co-processing method according to claim 1, wherein in S1, the flux includes quartz stone and limestone in such a ratio that a mass ratio of FeO to SiO ₂ in the molten state high zinc dross is 0.4 to 1.6:1, the mass ratio of CaO to SiO ₂ is 0.4-1.4:1, and the mass ratio of ZnO to the total mass of SiO ₂, feO, caO and ZnO is 0.4-0.8:1.

5. The co-processing method according to claim 1, wherein the oxygen concentration in the oxygen-enriched air in S1 and/or S2 is 40 to 80vol%.

6. A co-processing method according to any one of claims 1 to 5, wherein the oxidation furnace and the reduction furnace are communicated with each other through a chute to input molten high zinc slag in the oxidation furnace into the reduction furnace through the chute.

7. A co-processing method according to any one of claims 1-5, characterized in that in the zinc sulphide concentrate the Zn content is 30-55wt%, the S content is 15-35wt%, the Fe content is < 10wt%, the Si content is < 5wt%, the Pb content is < 3 wt%, and the Cl content is < 0.2wt%.

8. The co-processing method according to any one of claims 1 to 5, wherein in the industrial sodium sulfate waste salt, the content of Na is 15 to 25wt%, the content of S is 10 to 18 wt wt%, the content of Cl is < 2 wt%, the content of C is2 to 10 wt%, the content of H is1 to 5wt%, the content of O is 30 to 50wt%, and the content of N is < 5 wt%.

9. The synergistic process of any one of claims 1 to 5, wherein the reducing agent is one or more of pulverized coal, anthracite coal, coke.