Low-carbon smelting method of lead

Abstract

The invention belongs to the technical field of metallurgy, and provides a low-carbon smelting method of lead aiming at the problems that the heat efficiency of equipment is reduced, the reaction between PbS and PbO is limited, and the volatilization smoke dust rate is high due to material accumulation at low temperature due to high moisture of materials fed into a furnace in traditional lead smelting. The method comprises the following steps: S1, material drying: drying lead sulfide concentrate, quartz sand and calcium carbonate (or calcium oxide); s2, mixing and grinding ore: mixing and grinding the dried lead concentrate with quartz sand and calcium carbonate (or calcium oxide) in proportion; s3, reacting, namely blowing mineral powder into the melt in the reaction furnace for reacting twice; s4, performing gas-phase reaction on the flue gas, namely mixing the flue gas generated by two times of reaction and performing gas-phase reaction; and S5, discharging and recycling the slag, enabling the slag in S2 to enter S3 for reaction, and feeding the slag in S3 for subsequent process treatment. The method effectively overcomes the defects of a traditional process and improves the metallurgical effect.

Description

TECHNICAL FIELD

[0001] The application relates to a low-carbon smelting method of lead. BACKGROUND

[0002] The traditional smelting process of lead sulfide concentrate is the sintering-blast furnace method, which has been completely eliminated in China. At present, the mainstream process is the advanced direct lead smelting method, and the representative processes are the Kivcet process invented by the Soviet Union and the domestic bath smelting method (three-in-one furnace process): top-blowing-reduction-fuming, bottom-blowing-reduction-fuming and side-blowing-reduction-fuming. The direct lead smelting method fully utilizes the chemical heat generated by the combustion of the sulfuration furnace and the oxygen enrichment technology, greatly reduces the smelting energy consumption (80-120 kgce / lead bullion), realizes SO2 acid production, and makes a major breakthrough in energy consumption and environmental protection.

[0003] The Kivcet process concentrates the oxidation and reduction of lead sulfide concentrate in one smelting device, dry materials are added into the furnace to complete the desulfurization reaction in the gas phase, and the incompletely reacted lead sulfide falls to the bottom of the device to complete the interactive reaction to produce part of the lead bullion and desulfurization. The molten slag containing PbO enters the reduction zone and is reduced to lead bullion by coke under the action of electric heating. The reaction process mainly strengthens the gas-solid reaction of the desulfurization process. Chinese patent CN 101260479B is a flash smelting method of lead. The dry powdered lead sulfide concentrate is sprayed into a high-temperature reaction tower space together with oxygen through a nozzle in a floating state. The input amount of oxygen is controlled so that the oxidation rate of lead sulfide is 60%-80%, and the oxidation process of lead sulfide is completed. The generated melt falls into the sedimentation tank below the reaction tower, and through the interactive reaction of lead oxide and lead sulfide and the reduction reaction, lead bullion and slag are continuously generated. After clarification and layering, they are discharged from the lead discharge port and the slag discharge port respectively. The slag containing low lead can be discarded or further treated. The main metallurgical reactions are: PbS+O2=Pb+SO2, 2PbS+3O2=2PbO+2SO2, 2PbO+PbS=3Pb+SO2. The characteristics of the above process are that the oxidation is carried out in the gas phase reaction zone, and the interactive reaction is carried out in the molten pool below the metallurgical furnace. The required PbS and PbO for the interactive reaction are difficult to accurately control, the molten slag contains relatively high lead, and a carbonaceous reducing agent is also needed. The three-in-one furnace process completes the melting and desulfurization of the materials in one bath smelting furnace, and the high (rich) slag obtained is introduced into the reduction equipment to reduce the lead bullion from the molten slag by adding carbon coal / pulverized coal. The reduced molten slag is introduced into the fuming furnace for comprehensive recovery by spraying pulverized coal.

[0004] The existing triple furnace main oxidation-reduction-and fuming three process composition, oxidation in a rich oxygen molten pool smelting furnace, through the rich oxygen smelting and adding fuel to complete the sulfide conversion to oxide, get the SO2 flue gas to meet the requirements of sulfuric acid production, process makes full use of the heat of sulfide oxidation combustion and rich oxygen air to reduce the flue gas volume to get the flue gas to meet the requirements of sulfuric acid production and reduce the heat carried away by flue gas to improve the thermal efficiency of metallurgical furnace. Oxidation process is mainly based on sulfide material combustion and sulfate decomposition desulfurization, mainly based on PbS+O2=Pb+SO2 reaction, through PbS combustion to generate SO2 and release heat to melt the material, at the same time, a small amount of carbon fuel is added to ensure the melting of the material and inhibit the foaming slag, in this process, due to the reduction of carbon (PbO+CO=Pb+CO2) and the interaction (2PbO+PbS=3Pb+SO2), industry can produce 10~20% crude lead, get liquid high lead slag containing lead 40~55%, S≤1.5% into the reduction process, add appropriate amount of carbon, get crude lead and lead containing zinc (≤2.0%), zinc~20% and other valuable elements in the carbon powder or pulverized coal reduction slag into fuming furnace, further adjust the slag type fuming volatilization to enrich lead, zinc and valuable elements. At present, the energy consumption of crude lead is 80~120kgcet / t.

[0005] In the actual production process, the top blowing process and the bottom blowing process of the oxidation process rarely produce crude lead, and some factories even do not produce lead for use, the side blowing furnace crude lead yield is 10~20%, the crude lead oxidation section should be the reduction of lead (PbO+C=Pb+CO) of the interaction (2PbO+PbS=3Pb+SO2) oxidation of lead.

[0006] The existing triple furnace process feeding method is uniformly wet feeding, the material into the furnace is mixed with water (containing water 10±2%) to make granules (particle size 3~8mm) and then added from the feeding port to ensure that the material can enter the molten pool and reduce the powder material taken away with the flue gas to reduce the dust rate. The wet material added into the furnace after granulation is easy to form accumulation below the feeding port, PbS cannot quickly and uniformly mix with the molten slag to carry out mutual reaction, 10~20% crude lead can be produced in the oxidation section, the rest of the lead finally enters the molten slag in the form of PbO to form lead-rich slag, enters the reduction process by adding reducing agent (coal / coke) to reduce and produce crude lead again, the energy consumption is relatively high; at the same time, the water in the material evaporates in the furnace, consumes heat, not only reduces the thermal efficiency of the metallurgical furnace (the temperature of the metallurgical furnace decreases), but also the water vapor film formed during evaporation hinders the contact of PbS with PbO and PbS and O2, reduces the metallurgical reaction process in the smelting furnace, and the smelting reaction efficiency decreases; and the particle size of the material entering the molten pool is large, the melting speed and chemical reaction speed are limited, the smelting process time increases, and the production cost is relatively high.

[0007] Because PbS has a high volatile vapor pressure above 850℃, the current bottom blowing and side blowing bath smelting method is easy to accumulate material below the discharge port, the water in the material is concentrated in the material adding area, which causes the temperature of the discharge port area to be relatively low, although the oxygen-rich is sprayed into the bath to stir the bath, but the stirring intensity below the feeding port is insufficient to quickly mix the material with PbO, the amount of PbS in the area below the feeding port is concentrated, the residence time of PbS in the furnace is long, which causes the volatilization of PbS to increase, the dust rate is 18~25%, the processing capacity of the metallurgical equipment is reduced, and the cost is increased. The top blowing bath smelting is small in bath area, strong in stirring, although the material will not accumulate in the furnace, but the space above the bath is high (12~18m), the temperature is high, part of PbS volatilizes during the descending process, the dust is also high, 18~25%, the operation rate of the smelting equipment is reduced, and the cost is increased.

[0008] Meanwhile, the existing triple furnace lead smelting process has different SO2 in the oxidation and reduction sections, and the SO2 in the reduction section is low and cannot be directly used for acid production, which is difficult to treat and high in cost; the oxidation section dust is mainly PbS, and the reduction section dust is mainly PbO, the two dusts cannot contact in the gas phase to react 2PbO+PbS=3Pb+SO2, and remain in the flue gas, which is cooled, dusted and returned to smelting, thereby reducing the operation rate of the smelting equipment and increasing the cost. SUMMARY

[0009] In view of the defects of the above-mentioned traditional method, the purpose of the present application is to provide a low-carbon smelting method of lead, which solves the problems in traditional smelting that the water content of the material into the furnace is low, which leads to the decrease of the thermal efficiency of the equipment, the obstruction of the contact between PbS and PbO, the accumulation of the material and the local low temperature, which further aggravates the volatilization of PbS and the increase of the dust rate, limits the mutual reaction, and part of the smelting flue gas cannot be directly used for acid production, thereby affecting the metallurgical effect.

[0010] The technical implementation scheme of the present application is:

[0011] A low-carbon smelting method of lead, characterized by comprising the following steps:

[0012] S1, material drying: drying lead sulfide concentrate, quartz sand and calcium carbonate (calcium oxide);

[0013] S2, mixed grinding: the lead concentrate obtained by drying in S1 is mixed and ground with quartz sand and calcium carbonate (calcium oxide) in proportion respectively;

[0014] S3, reaction: the mineral powder obtained in S2 is added into the bath inside the reaction furnace by gas to carry out the first reaction and the second reaction;

[0015] S4, gas phase reaction: the flue gas generated by the two reactions in the reaction furnace is mixed and subjected to gas phase reaction again;

[0016] S5, slag discharge and recovery: the slag in the reaction furnace is discharged and sent to subsequent processes for further treatment, and the flue gas generated is sent to sulfur recovery treatment.

[0017] Preferably, in the S2 step, the dry lead sulfide concentrate is mixed with dry quartz sand and calcium carbonate (calcium oxide) respectively, and the ratio of lead concentrate to quartz sand (molar ratio of lead to SiO2) is 1.6-2.2:1, and the ratio of lead sulfide concentrate to calcium carbonate (calcium oxide) (molar ratio of lead to CaO) is 0.8-1.2:2.

[0018] Preferably, in the S3 step, the first reaction includes: using a reaction furnace, lead sulfide concentrate powder and quartz sand powder are directly sprayed into high-temperature liquid slag from a nozzle by oxygen-enriched air, and the air supply port is sprayed into the high-temperature liquid PbO•SiO2 molten pool through the nozzle to stir the molten pool slag, and the first reaction occurs; the reaction formula is: PbO+SiO2=PbO•SiO2; PbO+PbS=Pb+SO2; the second reaction includes: using a reaction furnace, dry PbS and calcium carbonate powder / oxide are mixed in proportion, and are directly and uniformly added into the molten PbO•SiO2 from the nozzle by low-oxygen-containing gas, and PbS, PbO•SiO2 and CaO are fully stirred and mixed uniformly in the high-temperature molten pool to rapidly complete the mutual reaction; the reaction formula is: 2PbO•SiO2+PbS+2CaO=3Pb+2CaO•SiO2+SO2 to produce crude lead, and other metal sulfides in the PbS concentrate complete the oxidation reaction to produce slag.

[0019] Preferably, the flue gas generated by the first reaction is mixed with the flue gas generated by the second reaction in the gas phase reaction zone of the reaction furnace to realize gas phase reaction; the reaction formula is 2PbO+PbS=3Pb+SO2.

[0020] Preferably, the combustion reaction and melting of PbS and quartz sand in the molten liquid are completed in the nozzle flame, and the PbS is completely combusted in the flame; in the S3 step, PbO•SO2 is rapidly generated by simultaneously adding PbS and quartz powder mixture during the oxidation of lead sulfide to reduce the reaction temperature and inhibit the volatilization of PbO.

[0021] Preferably, PbS and calcium carbonate / oxide powder are transported and uniformly sprayed in the molten pool by low-oxygen-containing gas to reduce the combustion consumption of PbS, and the low-oxygen-containing gas is dry flue gas discharged in the acid-making process, nitrogen gas produced in the oxygen-making process, air, etc.; the flue gas generated by the reaction furnace is first subjected to heat energy recovery by a heat energy recovery mechanism to dry the raw materials in the S1 step, and then subjected to treatment by a purification device.

[0022] Preferably, the part of the flue gas in the gas phase reaction zone is pressurized to return to the gas reaction zone to stir and mix the flue gas of the reaction 1 zone and the reaction 2 zone, so as to strengthen the gas phase reaction.

[0023] Preferably, the reaction furnace comprises a support frame, a reaction furnace and a sealing cover, the reaction furnace is arranged in the inside of the support frame, the reaction furnace comprises a furnace body, a partition plate, a first zone nozzle, a second zone nozzle and an opening furnace gate, the reaction furnace is a rectangular cavity structure with an upper opening, and the inside of the reaction furnace is divided into a first reaction zone and a second reaction zone by the partition plate, and one side of the first reaction zone and the second reaction zone is respectively provided with a first zone nozzle and a second zone nozzle.

[0024] Preferably, the partition plate is provided with a flow guide hole, one side of the first reaction zone and the second reaction zone is respectively provided with a first copper matte discharge gate and a slag discharge gate, the lower part of the first zone nozzle is provided with a first slag discharge gate, the upper and lower parts of the second zone nozzle are respectively provided with a first slag inlet, a second copper matte discharge gate and a lead discharge gate, and the lead discharge gate is located at the oblique lower part of the second copper matte discharge gate, and the reaction furnace is provided with a sealing cover above.

[0025] The present application has the following advantages:

[0026] 1. Compared with the existing molten pool smelting, the smelting temperature of the present application is reduced, the interactive reaction is accurately controllable, the oxygen consumption is reduced, the comprehensive energy consumption is reduced by 15-20 kgce / t of crude lead compared with the existing molten pool smelting, the SO2 concentration of the flue gas is small, the acid production is stable, the material is directly added to the molten pool and rapidly captured by the liquid slag, the dust rate is reduced to 5-10%, the treatment capacity is increased by 15-20%, and the safety hidden danger caused by the sudden reaction of the material accumulation under the feeding port of the existing molten pool smelting is effectively eliminated.

[0027] 2. The present application adopts an independently designed smelting furnace, can realize twice reaction operation, and the flue gas generated by the twice reaction can be mixed and then subjected to gas phase reaction, so as to realize integrated operation of the reaction. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The present application is a process flow chart.

[0029] Figure 2 The present application is a process flow chart of the furnace body part.

[0030] Figure 3 The present application is a structural schematic diagram of the reaction furnace.

[0031] Figure 4 The present application is a structural schematic diagram of the inside of the reaction furnace.

[0032] Figure 5A reaction furnace main view of the present application.

[0033] Meaning of reference signs in the drawing: 1-support frame, 2-sealing cover, 3-reaction furnace, 301-furnace body, 302-isolation plate, 303-first reaction zone, 304-second reaction zone, 305-flow guide hole, 306-first reaction zone nozzle, 307-first slag outlet, 308-first matte outlet, 309-second reaction zone nozzle, 310-first slag inlet, 311-lead outlet, 312-slag outlet, 313-starting material outlet, 314-flue gas outlet, 315-second matte outlet, DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings. It is hereby declared that the up, down, left, right, front, back, inner and outer orientation words appearing or about to appear in the present application are only based on the drawings of the present application, and are not specific limitations on the present application.

[0035] Example 1:

[0036] A low-carbon smelting method of lead, comprising the following steps:

[0037] S1, material drying: dry lead sulfide concentrate, quartz sand and calcium carbonate (calcium oxide);

[0038] S2, mixed grinding: the dried lead concentrate in step S1 is mixed and ground with quartz sand and calcium carbonate (calcium oxide) in proportion respectively;

[0039] S3, reaction: the mineral powder obtained in step S2 is added to the inside of the reaction furnace for first reaction and second reaction;

[0040] S4, gas phase reaction: the flue gas generated by the two reactions in the reaction furnace is mixed and subjected to gas phase reaction again;

[0041] S5, slag discharge and recovery: the slag in the reaction furnace is discharged, and the slag is sent to the subsequent process for further treatment, and the generated flue gas is sent to sulfur recovery treatment.

[0042] In step S2, the dried lead sulfide concentrate is mixed with the dried quartz sand and calcium carbonate (calcium oxide), and the proportion of lead concentrate to quartz sand is (molar ratio of lead to SiO2) 2:1, and the proportion of lead sulfide concentrate to calcium carbonate (calcium oxide) is (molar ratio of lead to CaO) 1:2.

[0043] In the S3 step, the first reaction includes: using a reaction furnace, the lead sulfide concentrate powder, quartz sand powder is directly sprayed into the high-temperature liquid slag by the oxygen-rich air from the nozzle, and the air supply port is sprayed into the high-temperature liquid PbO•SiO2 molten pool through the nozzle to stir the molten pool slag, and the first reaction occurs; the reaction formula is: PbO+SiO2=PbO•SiO2; PbO+PbS=Pb+SO2; the second reaction includes: using a reaction furnace, dry PbS and calcium carbonate powder / oxidation are mixed in proportion, and are directly and uniformly added to the molten PbO•SiO2 from the nozzle by the gas containing low oxygen, and the PbS, PbO•SiO2 and CaO are fully stirred and mixed uniformly in the high-temperature molten pool, and the mutual reaction is rapidly completed; the reaction formula is: 2PbO•SiO2+PbS+2CaO=3Pb+2CaO•SiO2+SO2 to produce crude lead, and other metal sulfides in the PbS concentrate complete the oxidation reaction to produce slag.

[0044] It should be noted that compared with the traditional smelting method, the whole process uses a reaction furnace integrated reaction operation, the lead sulfide concentrate powder and quartz sand powder are directly sprayed into the high-temperature liquid slag by the oxygen-rich air from the nozzle, and the high-temperature liquid PbO•SiO2 molten pool is introduced into the molten pool to stir the molten pool, so that the first reaction is carried out, the flue gas formed flows upward and enters the gas phase reaction zone, and the slag formed enters the second reaction chamber and is fully stirred and mixed with PbS, PbO•SiO2 and CaO inside to complete the mutual reaction rapidly, the flue gas formed enters the gas phase reaction zone, and the two flue gases are reacted again in the gas phase, PbS+3PbO=3Pb+SO2, the lead pollutants in the converted flue gas are converted into crude lead, the PbS and PbO dust suspended in the gas phase are converted into crude lead, the lead loss is reduced, and the total lead recovery rate is improved. The flue gas after the reaction enters the heat energy recovery equipment to recover the heat energy contained in the flue gas, and the recovered heat energy can be used for drying the materials in the S1 step, and then the flue gas enters the purification equipment to realize the flue gas purification operation.

[0045] It needs to be further explained that through the series design of the first reaction zone, the second reaction zone and the gas phase reaction zone in the reaction furnace, the lead sulfide is first converted into lead silicate slag by oxygen-rich air combined with quartz sand, then reduced by calcium powder and low-oxygen gas to produce crude lead, and finally the PbS and PbO dust in the flue gas is recovered by the gas phase reaction, realizing multi-stage closed-loop recovery of lead resources, greatly improving the total recovery rate; the SO2 generated by all reactions is concentrated for subsequent recovery and treatment, the unorganized discharge of lead compounds is reduced, and the environmental protection treatment cost is low; at the same time, the process has high integration degree, no additional recovery equipment is needed, different grades of raw materials can be adapted by adjusting the oxygen concentration and the proportioning ratio, and the smelting slag has stable properties and can be comprehensively utilized, the energy consumption and solid waste treatment pressure are lower than those of the traditional process, and economic benefits, environmental protection and operation flexibility are considered.

[0046] Example 2:

[0047] An industrial experiment was carried out in a 1.2m 2 , 0.7m 2 , 0.5m 2 , and 80m 3 smelting furnace. The quartz sand, lead sulfide concentrate and calcium carbonate were dried to a moisture content of 0.45%, then the dried lead sulfide concentrate and quartz sand were mixed at a Pb to SiO2 ratio of 1:1, the dried lead sulfide concentrate and calcium carbonate were mixed at a Pb to CaO ratio of 1:2, and were finely ground to 200 mesh or more. The mixed powder of lead sulfide concentrate and quartz sand was sprayed into the reaction furnace by 4 nozzles containing 62% oxygen, and the lead sulfide was oxidized and reacted with quartz to generate a molten pool temperature of 1085°C. Then the mixed powder of lead sulfide concentrate and quartz sand was sprayed into the molten pool by air, and the molten pool temperature was 1020°C. The molten slag contained 2.47% lead, the lead direct recovery rate was 92.67, the dust was 8.72%, the process smoke SO2 concentration was 7.8~8.6%, and the crude lead energy consumption was 60.62kgce / t.

[0048] Example 3:

[0049] An industrial experiment was carried out in a 1.2m 2 , 0.7m 2 , 0.5m 2 , and 80m 3Industrial experiments were conducted in the smelting facility. Quartz sand, lead sulfide concentrate, and calcium carbonate were dried to a water content of 0.78%. The dried lead sulfide concentrate and quartz sand were then mixed at a Pb:SiO2 ratio of 1:1, and the dried lead sulfide concentrate and calcium carbonate were mixed at a Pb:CaO ratio of 0.9:2. Both were finely ground to 200 mesh to achieve a purity of over 80%. The mixed lead sulfide concentrate and quartz sand powder was injected into the molten pool of the reactor through four nozzles with oxygen containing 72% oxygen. The lead sulfide oxidized and reacted with the quartz sand to form a molten pool at a temperature of 1130℃. Then, the mixed lead sulfide concentrate and quartz sand powder was injected into the molten pool through acid production tail gas (containing 12.3% oxygen). The molten pool temperature was 1000~1050℃. The slag contained 1.56% lead, the lead recovery rate was 92.96%, the dust content was 6.36%, the process flue gas SO2 concentration was 8.0%, and the crude lead energy consumption was 60.58 kgce / t.

[0050] Example 4:

[0051] In a 1.2m 2 0.7m of reaction I 2 0.5m of reaction II 2 80m gas phase reaction zone 3 Industrial experiments were conducted in the smelting facility. Quartz sand, lead sulfide concentrate, and calcium carbonate were dried to a moisture content of 1.02%. The dried lead sulfide concentrate and quartz sand were then mixed at a Pb:SiO2 ratio of 1.2:1, and the dried lead sulfide concentrate and calcium carbonate were mixed at a Pb:CaO ratio of 1.5:2. Both mixtures were finely ground to 320 mesh, achieving a purity of over 80%. The mixed lead sulfide concentrate and quartz sand powder was injected into the molten pool of the reactor through four nozzles using oxygen containing 75% oxygen. The lead sulfide oxidized and reacted with the quartz sand to form a molten pool at a temperature of 1230℃. The mixed lead sulfide concentrate and quartz sand powder was then injected into the molten pool via oxygen-generating tail gas, resulting in a molten pool temperature of 1030℃. The slag contained 1.23% lead, the lead recovery rate was 93.42%, the dust content was 10.17%, the process flue gas SO2 concentration was 8.8%, and the crude lead energy consumption was 58.32 kgce / t.

[0052] Example 5:

[0053] In a 1.2m 2 0.7m of reaction I 2 0.5m of reaction II 2 , gas phase reaction zone 100m 3 The smelting chamber and a 0.8m 2Industrial experiments were conducted in a reduction side-blown furnace. Quartz sand, lead sulfide concentrate, and calcium carbonate were dried to a water content of 0.67%. The dried lead sulfide concentrate and quartz sand were then mixed at a Pb to SiO2 ratio of 1.2:1, and the dried lead sulfide concentrate and calcium carbonate were mixed at a Pb to CaO ratio of 1.5:2. The mixtures were then finely ground to 200 mesh to achieve a water content of over 50%. Lead sulfide concentrate and quartz sand mixed ore powder are injected into the molten pool of a side-blown oxidation furnace through four nozzles with oxygen containing 65% oxygen. The lead sulfide oxidizes and reacts with the quartz sand to form a molten pool with a temperature of 1090℃. The resulting slag is placed in a reduction side-blown furnace. Acid production tail gas (containing 15.6% oxygen) is injected into the molten pool through four nozzles. The molten pool temperature is 1055℃. The slag contains 1.53% lead, the lead recovery rate is 93.18%, the dust content is 6.15% (oxidation + reduction), the SO2 concentration in the mixed flue gas is 6.9%, and the crude lead energy consumption is 55.76 kgce / t.

[0054] Example 6:

[0055] In a 1.2m 2 0.7m of reaction I 2 0.5m of reaction II 2 , gas phase reaction zone 100m 3 The smelting chamber and a 0.8m 2 Industrial experiments were conducted in a reduction side-blown furnace. Quartz sand, lead sulfide concentrate, and calcium carbonate were dried to a water content of 0.67%. The dried lead sulfide concentrate and quartz sand were then mixed at a Pb to SiO2 ratio of 1.2:1, and the dried lead sulfide concentrate and calcium carbonate were mixed at a Pb to CaO ratio of 1.5:2. The mixtures were then finely ground to 200 mesh to achieve a purity of over 80%. Lead sulfide concentrate and quartz sand mixed ore powder are injected into the molten pool of a side-blown oxidation furnace through four nozzles with oxygen containing 65% oxygen. Lead sulfide oxidizes and reacts with quartz to form a molten pool at a temperature of 1200℃. The resulting slag is placed in a reduction side-blown furnace. Oxygen-generated tail gas is injected into the molten pool through four nozzles, where the temperature of the molten pool is 1060℃. The slag contains 1.53% lead, the lead recovery rate is 93.32%, and the dust content is 5.06% (oxidation + reduction). The SO2 concentration in the mixed flue gas is 7.7%, and the energy consumption for crude lead is 53.62 kgce / t.

[0056] As can be seen from the comparison of the five embodiments, in the lead sulfide smelting process, the improvement of the fineness of the raw material (200 mesh pass rate of 80% or more or 320 mesh of 80%), the ratio of Pb to SiO2 of 1.2:1, the ratio of Pb to CaO of 1.5:2 of the raw material combination, the expansion of the gas phase reaction zone volume to 100m³, and the "oxidation furnace + interactive reduction side-blown furnace" process and equipment can significantly optimize the smelting effect: compared with the basic scheme (such as Example One) with low fineness of raw material and single furnace configuration, the optimal combination (Example Five) realizes the reduction of the energy consumption of crude lead from 60.62kgce / t to 53.62kgce / t, the reduction of the dust rate from 8.72% to 5.06%, the improvement of the lead direct recovery rate from 92.67% to 93.32%, the stable lead content in the slag below 1.53%, and the strong adaptability of the process to the water content of the raw material. The gas matching of oxygen-rich oxidation + low-oxygen reduction and the temperature range of 1060°C meet the requirements of each reaction, fully verifying the rationality and superiority of the optimization of the process parameters and equipment configuration. Moreover, the SO2 concentration of the flue gas is 8%, which meets the requirements of the acid-making process, solves the problem of low-concentration SO2 treatment in the existing three-furnace reduction furnace, improves the utilization rate of sulfur resources, and reduces the production cost.

[0057] The working principle of the technical solution is as follows:

[0058] As shown in Figure 1 and Figure 2 , the limestone, aluminum sulfide concentrate, and quartz sand are dried first, and then the dried limestone and aluminum sulfide concentrate are ground, and the ground quartz sand is mixed with related dust and melted by blowing in oxygen-rich air, and then interactive smelting is performed to obtain crude lead and slag (comprehensive recovery). The flue gas is sequentially treated by waste heat recovery, acid making, dust collection, and the like, and the flue gas generated in the process of treating the quartz sand and the like is treated by environmental protection. In another line, the aluminum sulfide concentrate is mixed with dried dust, quartz sand, and the like after drying and is blown in the first and second reaction zones, and the generated flue gas is treated by waste heat boiler, dust collection, acid making, and waste heat power generation, and the slag and the like also participate in the corresponding process. Finally, crude lead extraction, flue gas, and waste slag are treated in accordance with the regulations and resources are recovered.

[0059] As shown in Figures 3-5 , the reaction furnace includes a support frame 1, a reaction furnace 3, and a sealing cover 2. The reaction furnace 3 is arranged in the interior of the support frame 1. The reaction furnace 3 includes a furnace body 301, a partition plate 302, a first zone nozzle 306, a second reaction zone nozzle 309, and an opening furnace material port 313. The reaction furnace 3 is a rectangular cavity structure with an upper opening. The interior of the reaction furnace 3 is divided into a first reaction zone 303 and a second reaction zone 304 by the partition plate 302. The first reaction zone 303 and the second reaction zone 304 are respectively provided with the first reaction zone nozzle 306 and the second reaction zone nozzle 309.

[0060] It should be noted that the reaction furnace 3 is arranged inside the support frame 1, so that the whole reaction furnace is supported on the ground, and is convenient to be connected with the feeding system and the discharging system. Moreover, the inside of the furnace body 301 is divided into the first reaction area 303 and the second reaction area 304 by the partition plate 302, so that the material can be reacted in the first reaction area to realize the first step of lead extraction, the generated flue gas enters the third reaction area, and the generated slag can be introduced into the second reaction area to realize the second reaction operation, and then the generated lead and lead material are discharged, and the generated flue gas enters the third reaction area.

[0061] It should be noted that the third reaction area is the chamber directly above the first reaction area 303, and the flue gas generated by the two reactions is mixed with each other during the upward rising process, so as to realize the gas phase reaction. In the gas phase reaction process, the flue gas generated by the two reactions needs to be mixed, so as to convert the lead pollutants in the converted flue gas, convert the PbS and PbO dust suspended in the gas phase into crude lead, reduce the lead loss, and improve the total lead recovery rate.

[0062] As shown in Figures 3-5 The partition plate 302 is provided with a flow guide hole 305; one side of the first reaction area 303 and the second reaction area 304 is respectively provided with a first lead outflow port 308 and a slag outflow port 312; the lower part of the first reaction area nozzle 306 is provided with a first slag outflow port 307, the upper and lower parts of the second reaction area nozzle 309 are respectively provided with a first slag inflow port 310, a second lead outflow port 315 and a lead outflow port 311, and the lead outflow port 311 is located at the obliquely lower part of the second lead outflow port 315; and the reaction furnace 3 is provided with a sealing cover 2 directly above.

[0063] It should be noted that the first lead outflow port 308 and the second lead outflow port 315 are respectively used for discharging the lead generated after the reaction, and the first reaction area nozzle 306 and the second reaction area nozzle 309 are used for introducing the material.

[0064] The lead sulfide and quartz sand mixed powder, oxygen-enriched air are introduced from the material feeding port and reacted in the molten slag in the first reaction zone 303, PbS+SiO2+O2=PbO•SiO2+SO2, the generated copper sulfide is discharged from the first copper matte discharge port 308, the generated PbO•SiO2 molten slag is introduced into the second reaction zone 304 through the flow guide hole 305 to perform the second reaction, the lead sulfide and calcium powder mixed powder, air are introduced from the second reaction zone spout 309 of the second reaction zone 304, the reaction formula is: 2PbO•SiO2+PbS+2CaO=3Pb+2CaO•SiO2+SO2, the crude lead is discharged from the lead discharge port 311, the smelting slag is discharged from the slag discharge port 312, the flue gas generated in the second reaction zone 304 is introduced into the third reaction zone and reacted with the PbO flue dust generated in the first reaction of the first reaction zone 303, the reaction formula is: PbS+3PbO=3Pb+SO2; the smelting flue gas is recovered by the heat energy recovery equipment and the flue gas purification equipment.

[0065] The embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application.

Claims

1. A low-carbon smelting method for lead, characterized in that, Includes the following steps: S1. Material drying: Dry lead sulfide concentrate, quartz sand, and calcium carbonate (calcium oxide); S2. Mixed grinding: The lead concentrate obtained from drying in step S1 is mixed and ground with quartz sand and calcium carbonate (calcium oxide) in proportion. S3, Reaction: The mineral powder obtained in step S2 is added to the molten pool inside the reactor via gas to carry out the first and second reactions; S4, Gas-phase reaction: The flue gas produced by the two reactions in the reactor is mixed and then subjected to a gas-phase reaction again; S5. Slag Discharge and Recovery: The slag in the reactor is discharged and sent to subsequent processes for further treatment. The generated flue gas is sent for sulfur recovery treatment.

2. A low-carbon lead smelting method according to claim 1, characterized in that, In step 2, the dried lead sulfide concentrate is mixed with dried quartz sand and calcium carbonate (calcium oxide) respectively, and the ratio of lead concentrate to quartz sand (lead to SiO2 ratio) is 1.6-2.2:1, and the ratio of lead sulfide concentrate to calcium carbonate (calcium oxide) is 0.8-1.2:2 (lead to CaO ratio).

3. A low-carbon lead smelting method according to claim 1, characterized in that, In step S3, the first reaction includes: using a reactor, lead sulfide concentrate powder and quartz sand powder are directly injected into the high-temperature liquid slag through a nozzle using oxygen-enriched air, while at the same time, air is injected into the high-temperature liquid PbO•SiO2 molten pool through a nozzle to stir the molten pool slag, and the first reaction occurs. The chemical formulas for the reactions are: PbO + SiO2 = PbO•SiO2; PbO + PbS = Pb + SO2; The second reaction involves: using a reactor, mixing dry PbS with calcium carbonate powder / oxidation in a certain proportion, and directly and uniformly adding low-oxygen gas from the nozzle into molten PbO•SiO2. In the high-temperature molten pool, PbS, PbO•SiO2 and CaO are thoroughly stirred and mixed evenly to quickly complete the interactive reaction. The chemical formula of the reaction is: 2PbO•SiO2+PbS+2CaO=3Pb+ 2CaO•SiO2+SO2, which produces crude lead, and the other metal sulfides in the PbS concentrate undergo oxidation and melt to produce slag.

4. A low-carbon lead smelting method according to claim 1, characterized in that, The flue gas produced by the first reaction and the flue gas produced by the second reaction are mixed in the gas phase reaction zone of the reactor to achieve a gas phase reaction; the chemical formula of the reaction is 2PbO + PbS = 3Pb + SO2.

5. A low-carbon lead smelting method according to claim 1, characterized in that, PbS and sand complete the combustion reaction and melting in the nozzle flame within the molten liquid, and PbS is completely burned in the flame; In step S3, during the oxidation of lead sulfide, a mixture of PbS and quartz powder is added simultaneously to rapidly generate PbO•SO2, thereby lowering the reaction temperature and inhibiting the volatilization of PbO.

6. A low-carbon lead smelting method according to claim 1, characterized in that, PbS and calcium carbonate / oxide powder are transported and uniformly injected into the molten pool using a low-oxygen gas to reduce PbS combustion consumption. The low-oxygen gas includes the dried flue gas emitted from the acid production process, nitrogen produced from oxygen production, and air. The flue gas generated in the reactor is first recovered through a heat recovery mechanism to dry the raw materials in step S1, and then treated by a purification device.

7. A low-carbon lead smelting method according to claim 1, characterized in that, A portion of the flue gas from the gas phase reaction zone is pressurized and returned to the gas reaction zone to stir and mix the flue gas from reaction zone 1 and reaction zone 2, thereby enhancing the gas phase reaction.

8. A low-carbon lead smelting method according to claim 1, characterized in that, The reactor includes a support frame (1), a reactor (3) and a sealing cover (2). The reactor (3) is located inside the support frame (1). The reactor (3) includes a furnace body (301), an isolation plate (302), a first zone nozzle (306), a second zone nozzle (309) and a furnace opening port (313). The reactor (3) is a rectangular cavity structure with an opening at the top. The interior of the reactor (3) is divided into a first reaction zone (303) and a second reaction zone (304) by the isolation plate (302). The first reaction zone (303) and the second reaction zone (304) are respectively provided with a first reaction zone nozzle (306) and a second reaction zone nozzle (309) on their sides.

9. A low-carbon lead smelting method according to claim 8, characterized in that, The isolation plate (302) is provided with flow guide holes (305); A first matte outlet (308) and a slag outlet (312) are respectively provided on one side of the first reaction zone (303) and the second reaction zone (304). The first reaction zone nozzle (306) is provided with a first slag outlet (307) at its lower part, and the second reaction zone nozzle (309) is provided with a first slag inlet (310), a second copper matte outlet (315) and a lead outlet (311) at its upper and lower parts respectively, and the lead outlet (311) is located at the lower part of the second copper matte outlet (315); A sealing cover (2) is provided directly above the reactor (3).

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