Method for redox smelting of lead-zinc material

Abstract

The application discloses a kind of lead-zinc material oxidation reduction smelting method, it is related to pyrometallurgical technical field, comprising the following steps: step one: batching;Step two: granulation;Step three: oxidation smelting;Step four: reduction smelting, after desulfurization, lead-zinc oxide melt is added to side-blown furnace, add granular coal, granular coal accounts for 12% to 14% of the weight of lead-zinc oxide melt, and oxygen-enriched air is introduced to carry out reduction smelting, water gas is added in the upper space of furnace, and the volume ratio of furnace gas (H2+CO) / CO2 is controlled to be 1.5-2.0;Step five: fuming;Step six: condensation separation;Step seven: rectification.The application adds water gas in the upper space of reduction side-blown furnace, and the volume ratio of furnace gas (H2+CO) / CO2 is controlled to be 1.5-2.0, and oxygen-enriched air can be completely combusted, avoiding the possibility of zinc vapor generating zinc oxide.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pyrometallurgy, in particular to a method for oxidizing and reducing smelting of lead-zinc materials. BACKGROUND

[0002] Currently, there is only one method for simultaneously producing lead and zinc from lead-zinc materials, which is closed blast furnace zinc smelting. After sintering the lead-zinc materials, they are added to the blast furnace. Lead is produced in liquid form from the lower part of the furnace, and zinc is volatilized in vapor form from the upper part of the furnace into the condenser to produce crude zinc. This method has the characteristics of wide adaptability to raw materials and short process flow, but also has problems such as large sintering and crushing equipment, poor waste heat utilization, and consumption of coke for blast furnace.

[0003] With the development of oxygen-enriched side-blown smelting technology, metallurgical workers are also studying the use of this process to treat lead-zinc materials. However, during the reduction process, zinc vapor is easily oxidized to zinc oxide, resulting in a decrease in zinc recovery. At the same time, in the existing technology, it is often difficult to accurately control the proportioning of the materials and the smelting conditions, resulting in an imbalance in the recovery rates of lead and zinc during the smelting process, increasing the difficulty of subsequent separation. SUMMARY

[0004] The purpose of the present application is to provide a method for oxidizing and reducing smelting of lead-zinc materials to solve the problems raised in the background art.

[0005] In order to achieve the above-mentioned purpose, the present application provides the following technical solution: a method for oxidizing and reducing smelting of lead-zinc materials, which principle is to use oxygen in the air to oxidize and desulfurize the lead-zinc materials, and to reduce the desulfurized lead-zinc oxides into zinc vapor and liquid lead using carbon, the chemical reaction formula is as follows:

[0006] ZnS + 1.5O2 → ZnO + SO2

[0007] PbS + 1.5O2 → PbO + SO2

[0008] ZnO + CO → Zn (gas) + CO2

[0009] PbO + CO → Pb (liquid) + CO2

[0010] In order to prevent zinc vapor from being oxidized to zinc oxide, water gas is added to the upper space of the reduction side-blown furnace to maintain a stable reducing atmosphere, which specifically includes the following steps:

[0011] Step one: proportioning, the lead-zinc materials and flux are proportioned in the proportioning bin, the lead-zinc materials include lead concentrate, zinc concentrate, lead-zinc mixed ore, and lead-zinc containing miscellaneous materials, the Pb / Zn weight ratio is required to be 0.4-0.6, the total content of lead and zinc is 30%-60%, and the sulfur content of the mixed material is 18%-24%;

[0012] Step two: granulation, the prepared mixture is added into a cylindrical granulator for mixing and granulation, and the granulated material is required to have a particle size of 8-10 mm and a water content of 8%-10%;

[0013] Step three: oxidative smelting, the granulated material is added into a side-blown furnace with 5-10 mm particle coal, the 5-10 mm particle coal accounts for 6%-8% of the weight of the material, and oxygen-rich air is introduced for oxidative smelting, the produced dust-containing flue gas is sent to acid production after waste heat utilization and dust collection, and the produced lead-zinc oxide melt is sent to reduction smelting;

[0014] Step four: reduction smelting, the desulfurized lead-zinc oxide melt is added into a side-blown furnace with 5-10 mm particle coal, the 5-10 mm particle coal accounts for 12%-14% of the weight of the lead-zinc oxide melt, and oxygen-rich air with an oxygen concentration of 45-55 vol% is introduced for reduction smelting, the reduction flue gas has a composition of Zn: 10-15 vol%, CO: 8-12 vol%, and CO2: 20-26 vol%, water gas is added into the upper space of the furnace, the volume ratio of (H2+CO) / CO2 is controlled to be 1.5-2.0, the produced zinc vapor-containing furnace gas is sent to a lead rain condenser, the produced reduction slag is sent to a fuming furnace for blowing, and crude lead is produced by reduction, which is further refined to remove impurities;

[0015] Step five: fuming, the reduction slag is sent to a fuming furnace, and pulverized coal is sprayed into the furnace for fuming and blowing, and the pulverized coal accounts for 18%-20% of the weight of the reduction slag;

[0016] Step six: condensation and separation, the zinc vapor-containing flue gas produced from the reduction side-blown furnace is sent to a lead rain condenser for cooling, the condensing medium is lead liquid, the lead liquid captures the zinc vapor to form lead-zinc liquid which is sent to a separation system, the furnace gas is burned to recover heat value, and lead and zinc are separated by clarification due to different specific gravities;

[0017] Step seven: rectification, the crude zinc liquid separated from the lead rain condenser is sent to a rectification furnace.

[0018] Further, in step one, the lead-zinc-containing impurities are composed of dust and dross, and the fluxes include limestone, quartz, iron chips or iron sulfide.

[0019] Further, in step three, the oxygen concentration of the introduced oxygen-rich air is 70-80 vol%, the control temperature of the oxidative smelting is 1200-1250℃, and the time is 2-2.5 h.

[0020] Further, in step four, the control temperature of the reduction smelting is 1250-1300℃, and the time is 2-2.5 h.

[0021] Further, in the step four, the producer gas is a mixed gas generated by the reaction of solid fuel coal with gasification agent, water vapor under high temperature condition, and the volume ratio of the producer gas to the reducing flue gas is 40-60 vol%, the composition of the producer gas is H2: 40%-50 vol%, CO: 30%-40 vol%, CO2: 5%-10 vol%, and the temperature is 600-700℃.

[0022] Further, in the step five, the control temperature of the fuming and blowing is 1250-1300℃, and the time is 2-2.5h.

[0023] Further, in the step five, the dust-containing flue gas is sent to the flue gas treatment system after waste heat utilization and dust collection, and the obtained zinc oxide is returned to the batching device, and the obtained slag is sold after water quenching.

[0024] Further, in the step six, the lower lead liquid is returned to the lead rain condenser for recycling, and the upper zinc liquid is introduced into the zinc storage tank to obtain crude zinc liquid, and the high-temperature lead liquid in the separation system is cooled by water vapor to 100-120℃.

[0025] Further, in the step seven, the rectification furnace includes a lead tower and a cadmium tower, the zinc liquid flows into the lead tower, most of the zinc and the contained cadmium volatilize in vapor state at a temperature of 750-850℃, and the lead and other high-boiling-point impurities are discharged in liquid alloy for separation, the cadmium-containing zinc produced by the lead tower is introduced into the cadmium tower by a chute, and zinc and cadmium are separated at a temperature of 800-900℃, and the pure zinc liquid flows into the pure zinc tank from the lower part to obtain the rectified zinc.

[0026] In the above technical solution, the present application has the following technical effects and advantages:

[0027] 1. The steady-state reduction control technology is adopted, the producer gas is added to the upper space of the reduction side-blown furnace, the volume ratio of the furnace gas (H2+CO) / CO2 is controlled to be 1.5-2.0, the oxygen-enriched air can be completely combusted, and the possibility of zinc vapor generating zinc oxide is avoided.

[0028] 2. For the lead-zinc mixture, which includes lead concentrate, zinc concentrate, lead-zinc mixed ore, and lead-zinc-containing miscellaneous materials, the batching ratio is accurately controlled, the weight ratio of Pb / Zn is 0.4-0.6, the total content of lead and zinc is 30%-60%, and the sulfur content of the mixture is 18%-24%, so that the adaptability to different materials in the smelting process is ensured, and the recovery rate of lead and zinc is improved.

[0029] 3. The lead rain condenser is suitable for the fluctuation of the zinc vapor concentration in the furnace gas, can handle a large amount of furnace gas, and can be used for large-scale industrial production.

[0030] 4. The lead and zinc are smelted by side-blown furnace, the zinc is volatilized by steam and recovered by condensation, the lead is recovered by liquid, the lead and zinc are recovered in the same furnace, the lead recovery rate is >97%, and the zinc recovery rate is >95%. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art according to these drawings.

[0032] Figure 1 The process flow chart of the present application. DETAILED DESCRIPTION

[0033] In order to make those skilled in the art better understand the technical solutions of the present application, the present application will be further described in detail with reference to the drawings.

[0034] The water gas used in the present application is a mixed gas generated by the reaction of solid fuel coal with gasification agent and steam under high temperature conditions, and the main components are as follows: H2: 40-50vol%, CO: 30-40vol%, CO2: 5-10vol%.

[0035] The device used in the present application includes: a batching bin, a cylindrical granulator, an oxidation side-blown furnace, a reduction side-blown furnace, a fuming furnace, a lead rain condenser, a separation system, and a rectification furnace.

[0036] Example 1: Please refer to Figure 1 The present application provides a method for oxidizing and reducing smelting of lead and zinc materials, comprising the following steps:

[0037] Step 1: Batching, the lead and zinc materials and fluxes are batched through a batching bin, the lead and zinc materials include lead concentrate, zinc concentrate, lead-zinc mixed ore, and lead-zinc containing miscellaneous materials, the fluxes include limestone, quartz, iron chips or iron sulfide, the weight ratio of Pb / Zn is 0.4-0.6, the total content of lead and zinc is 30%-60%, and the sulfur content of the mixed material is 18%-24%;

[0038] Step 2: Granulation, the mixed material is mixed and granulated in a cylindrical granulator, the particle size of the granulated material is 8-10mm, and the water content is 8%-10%;

[0039] Step 3: Oxidation smelting, the granulated material is added into a side-blown furnace after being mixed with 5mm granular coal, the proportion of 5mm granular coal in the weight of the material is 6%, 70vol% oxygen-rich air is introduced for oxidation smelting, the temperature is controlled at 1200℃, the time is 2h, the produced dust-containing flue gas is sent to acid production after waste heat utilization and dust collection, and the produced lead and zinc oxide melt is sent to reduction smelting.

[0040] Step four: reduction smelting, the desulfurized lead-zinc oxide melt is added into the side-blown furnace, 5mm granular coal is added, the proportion of 5mm granular coal accounts for 12% of the weight of the lead-zinc oxide melt, 45vol% oxygen-rich air is introduced for reduction smelting, the temperature is controlled at 1250℃, the time is 2h, reduction flue gas is produced, the composition of the reduction flue gas is Zn: 10-15vol%, CO: 8-12vol%, CO2: 20-26vol%, water gas is added into the upper space of the furnace, the temperature is 600℃, the volume accounts for 40vol% of the amount of reduction flue gas, the volume ratio of (H2+CO) / CO2 of the furnace gas is controlled at 1.5-2.0, the zinc-containing vapor furnace gas produced is sent to the lead rain condenser, the reduction slag produced is sent to the fuming furnace for blowing, the reduction produced crude lead is recycled, and impurities are removed through further refining in the later stage;

[0041] Step five: fuming, the reduction slag is put into the fuming furnace, pulverized coal is sprayed into the furnace for fuming and blowing, the proportion of pulverized coal accounts for 18% of the mass of the reduction slag, the temperature is controlled at 1250℃, the time is 2h, the dust-containing flue gas produced is sent to the flue gas treatment system after waste heat utilization and dust collection, the zinc oxide collected by dust collection is returned to the batching, and the furnace slag produced is treated by water quenching;

[0042] Step six: condensation and separation, the zinc-containing vapor is put into the lead rain condenser for cooling, the condensing medium is lead liquid, the lead liquid traps the zinc vapor to form lead-zinc liquid which is put into the separation system, the lead and zinc are separated and clarified due to the difference in specific gravity, the lower layer of lead liquid is returned to the lead rain condenser for recycling, and the upper layer of zinc liquid is sent to the zinc storage tank to produce crude zinc liquid, and the high-temperature lead liquid in the separation system is cooled by water vapor to 100℃;

[0043] Step seven: rectification, the crude zinc liquid separated is put into the rectification furnace for rectification, the rectification furnace includes a lead tower and a cadmium tower, the zinc liquid flows into the lead tower, most of the zinc and the cadmium contained therein are volatilized in vapor state at a temperature of 750℃, while the lead and other high-boiling-point impurities are discharged in liquid alloy for separation, the cadmium-containing zinc produced by the lead tower is introduced into the cadmium tower by a chute, and zinc and cadmium are separated at a temperature of 800℃, and the pure zinc liquid is sent to a pure zinc tank from the lower part to obtain rectified zinc.

[0044] Example two: the weight ratio of lead and zinc in the lead-zinc material is 0.6, the total content of lead and zinc is 32%, and the sulfur content of the mixed material is 19%, the above steps of example one are carried out for oxidation and reduction smelting, the composition of the reduction flue gas produced is Zn: 9vol%, CO: 10vol%, CO2: 22vol%, the water gas produced in the upper space of the reduction furnace is 45vol% H2, 35vol% CO, and 8vol% CO2, the volume ratio of the mixed furnace gas (H2+CO) / CO2 is 1.7, the zinc-containing vapor furnace gas is put into the lead rain condenser to recover zinc, the reduction produced crude lead is blown in the fuming furnace. The final lead recovery rate is 97.2%, and the zinc recovery rate is 95.6%.

[0045] Example three: Pb / Zn weight ratio of lead-zinc material is 0.5, total content of lead and zinc is 45%, sulfur content of mixed material is 21%, the redox smelting is carried out according to the above steps of example one, the composition of reduction flue gas is Zn: 10vol%, CO: 9vol%, CO2: 23vol%, the producer gas with the composition of H2: 48vol%, CO: 34vol%, CO2: 9vol% is added into the upper space of reduction furnace, the mixed furnace gas (H2+CO) / CO2 volume ratio is 1.6, the zinc-containing vapor furnace gas enters into lead rain condenser to recover zinc, the reduction produces crude lead, the reduction slag enters into converter to be blown, the final lead recovery rate is 97.8%, and the zinc recovery rate is 96.1%.

[0046] Example four: Pb / Zn weight ratio of lead-zinc material is 0.4, total content of lead and zinc is 56%, sulfur content of mixed material is 23%, the redox smelting is carried out according to the above steps of example one, the composition of reduction flue gas is Zn: 11vol%, CO: 8vol%, CO2: 24vol%, the producer gas with the composition of H2: 44vol%, CO: 40vol%, CO2: 7vol% is added into the upper space of reduction furnace, the mixed furnace gas (H2+CO) / CO2 volume ratio is 1.6, the zinc-containing vapor furnace gas enters into lead rain condenser to recover zinc, the reduction produces crude lead, the reduction slag enters into converter to be blown, the final lead recovery rate is 98.1%, and the zinc recovery rate is 96.8%.

[0047] The above only describes certain exemplary embodiments of the present application by way of illustration, and it is needless to say that the described embodiments can be modified in various ways without departing from the spirit and scope of the present application for those skilled in the art. Therefore, the above figures and description are illustrative in nature and should not be understood as limiting the scope of protection of the claims of the present application.

Claims

1. A method for the oxidative and reductive smelting of lead-zinc material, characterized in that, The method comprises the following steps: Step one: batching, the lead-zinc material and flux are batched in a batching bin, the lead-zinc material comprises lead concentrate, zinc concentrate, lead-zinc mixed ore, lead-zinc containing miscellaneous material, the required Pb / Zn weight ratio is 0.4-0.6, the total content of lead and zinc is 30%-60%, and the sulfur content of the mixed material is 18%-24%; Step two: granulation, the mixed material is added into a cylindrical granulator for mixing and granulation, the particle size of the material after granulation is 8-10 mm, and the water content is 8%-10%; Step three: oxidation smelting, the granulated material is added into a side-blown furnace after being mixed with 5-10 mm granular coal, the proportion of the 5-10 mm granular coal in the weight of the material is 6%-8%, oxygen-rich air is introduced for oxidation smelting, the dust-containing flue gas generated is sent to an acid production system after waste heat utilization and dust collection, and the lead-zinc oxide melt generated is sent to a reduction smelting system; Step four: reduction smelting, the lead-zinc oxide melt after desulfurization is added into a side-blown furnace, 5-10 mm granular coal is added, the proportion of the 5-10 mm granular coal in the weight of the lead-zinc oxide melt is 12%-14%, oxygen-rich air with an oxygen concentration of 45-55 vol% is introduced for reduction smelting, reduction flue gas is generated, the composition of the reduction flue gas is Zn: 10-15 vol%, CO: 8-12 vol%, and CO2: 20-26 vol%, water gas is added into the upper space of the furnace, the volume ratio of H2+CO to CO2 in the furnace gas is controlled to be 1.5-2.0, the zinc-containing vapor furnace gas generated is sent to a lead rain condenser, the reduction slag generated is sent to a fuming furnace for blowing, and crude lead is generated by reduction, which is further refined to remove impurities; Step five: fuming, the reduction slag is sent to a fuming furnace, and pulverized coal is sprayed into the furnace for fuming and blowing, the proportion of the pulverized coal in the weight of the reduction slag is 18%-20%; Step six: condensation and separation, the zinc-containing vapor generated from the reduction side-blown furnace is sent to a lead rain condenser for cooling, the condensing medium is lead liquid, the lead liquid traps the zinc vapor to form lead-zinc liquid, which is sent to a separation system, the furnace gas is burned to recover heat value, and lead and zinc are separated by clarification due to different specific gravities; Step seven: rectification, the crude zinc liquid separated from the lead rain condenser is sent to a rectification furnace.

2. A method of redox smelting of lead-zinc material according to claim 1, characterized in that: In step one, the lead-zinc containing miscellaneous material is composed of dust and dross, and the flux comprises limestone, quartz, iron filings or iron sulfide.

3. A method of redox smelting of lead-zinc material according to claim 1, characterized in that: In step three, the oxygen concentration of the oxygen-rich air introduced is 70-80 vol%, the control temperature of the oxidation smelting is 1200-1250℃, and the time is 2-2.5 h.

4. A method of redox smelting of lead-zinc material according to claim 1, characterized in that: In step four, the control temperature of the reduction smelting is 1250-1300℃, and the time is 2-2.5 h.

5. A method of redox smelting of lead-zinc materials according to claim 1, characterized in that: In step four, the water gas generated by the solid fuel coal under high temperature conditions is a mixed gas generated by reacting with a gasification agent and steam, the volume ratio of the water gas to the reduction flue gas is 40-60 vol%, the composition of the water gas is H2: 40%-50 vol%, CO: 30%-40 vol%, and CO2: 5%-10 vol%, and the temperature is 600-700℃.

6. A method of lead-zinc material oxidation-reduction smelting according to claim 1, characterized in that: In step five, the control temperature of the fuming and blowing is 1250-1300℃, and the time is 2-2.5 h.

7. A method of redox smelting of lead-zinc materials according to claim 1, characterized in that: In the fifth step, the dust-containing flue gas is sent to the flue gas treatment system after waste heat utilization and dust collection, and the collected zinc oxide is returned to the batching system, and the produced slag is quenched in water and sold.

8. A method of redox smelting of lead-zinc materials according to claim 1, characterized in that: In the sixth step, the lower layer lead liquid is returned to the lead rain condenser for recycling, and the upper layer zinc liquid enters the zinc storage tank to produce crude zinc liquid, and the high-temperature lead liquid in the separation system is cooled to 100-120℃ by water vapor.

9. A method of redox smelting of lead-zinc materials according to claim 1, characterized in that: In the seventh step, the rectification furnace includes a lead tower and a cadmium tower, the zinc liquid flows into the lead tower, most of the zinc and the cadmium contained therein are volatilized in vapor state at a temperature of 750-850℃, while the lead and other high-boiling-point impurities are discharged in liquid alloy for separation, the cadmium-containing zinc produced by the lead tower is introduced into the cadmium tower by a chute, and at a temperature of 800-900℃, zinc and cadmium are separated, and the pure zinc liquid enters the pure zinc tank from the lower part to obtain the rectified zinc.

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