Summary of lead anode mud smelting technology and feasibility of electrothermal continuous smelting Zhou Hongwu Beijing Nonferrous Metals Research Institute, Beijing 100088) The wet process has been applied and developed in several domestic lead plants, but the technical status and basic objectives of the technology are still There is a certain gap. The fire method has been greatly developed. Some foreign smelters have adopted molten pool smelting and oxygen-enriched injection oxidative refining technology, which greatly improved production efficiency.
The paper introduces the main points of the feasibility of the lead anode mud electrothermal continuous melting technology scheme, and believes that the technology has good applicability.
1 The general composition and characteristics of lead anode mud are extremely muddy. Almost all of the gold, silver and antimony contained in the crude lead anode enter the anode slime, while some or most of the arsenic, antimony, copper, etc. enter the anode slime. The composition of the anode mud is mainly determined by the coarse lead anode plate used, and the various components have a large fluctuation range, but the total content of elements such as silver, lead, antimony, bismuth and copper and arsenic generally reaches 70. The elemental state of the newly produced lead anode mud is mostly a metal state or an intermetallic compound. Silver is basically free of elemental matter, a small part exists in AgCl, and most of it exists in the state of Ag3Sb and Ag-Sb. The gold content is generally low, and the gold particles are very finely embedded. The accumulated lead anode mud can be heated up to 70 7 or more. After 10 days, the anode mud water can be reduced to about 10. The lead, bismuth and antimony in the anode mud can basically exist in the form of oxide. . This provides a good basis for the reduction smelting or wet acid leaching of lead anode mud. However, lead anode mud does not require a very complete degree of oxidation during fire smelting.
2 Basic Process and Characteristics of Lead Anode Sludge Treatment At present, there are basically three ways to treat lead anode mud: one is fire-electrolysis treatment, and some factories mix and smelt lead anode mud and copper anode mud; Wet process; third is the wet-fire combined process.
There are many lead smelters in China. The process of treating lead anode mud should be selected according to the specific situation. The fire law processing flow was introduced to Zhou Hongwu 1940-), male, Changzhou, Jiangsu, senior engineer, engaged in nonferrous metallurgy research.
The process still has the characteristics of simple process and equipment; the combination of wet or wet-fire method also has its advantages.
2.1 Wet treatment process of lead anode mud The principle flow of the whole wet process of M treatment lead anode mud is: lead anode mud is first leached with acid to make impurities, so that Bi, Sb, Cu, A; etc. all enter the leachate; then chlorine The gold is reduced, and the gold powder is reduced from the gold liquid; the silver powder is removed from the slag by sodium sulfite or ammonia, and the silver powder is reduced from the solution; the gold and silver powder are melt-cast to obtain the gold ingot and the silver ingot; The method further obtains intermediate products such as ruthenium and osmium from the acid leaching solution, and obtains the product after treatment to realize comprehensive recycling. For lead anode muds with low gold content, it is also studied in the wet process to extract gold by means of extraction or by ion exchange resin.
The lead electrolytic refining produced by a certain smelter in Henan has a high anode niobium and adopts the traditional fire treatment process. The process has the disadvantages of low metal recovery rate, long operation time of blowing volatiles, high fuel consumption, large metal loss, short furnace life and poor working environment. In order to overcome the above shortcomings and shorten the gold and silver production cycle, in 1984, the plant cooperated with a southern industrial university to carry out the wet process test. In 1986, the lead anode mud wet process was first used for production. After nearly 10 years of Improvement and expansion, the annual treatment of lead anode mud increased from the original 721 to 500t. Several domestic factories have gradually adopted the wet process.
It is generally believed that the main advantage of wet production is the shortening of the production cycle of gold and silver. When the fire production process was used, it took 3 months for the anode mud to get out of the gold and silver products. Now, as long as 20 days, the product can be taken out, which accelerates the capital turnover of the factory. The basic objectives of the wet process technology are: 1 step acid leaching to enrich gold and silver, most heavy non-ferrous metal impurities enter the leachate; 2 recover valuable metals such as barium and strontium from the leaching solution of the leachate, from the leaching residue Recycling lead, arsenic into the neutralization slag of the waste liquid; 3 can directly obtain gold and silver products from the wet process; 4 eliminate pollution.
In the past 10 years, the wet-processed lead anode mud has been greatly improved, and it has been widely used in domestic lead plants. However, there are still some major problems in the wet process, so that it still has a long distance from the basic target: 1 The purity of gold powder and silver powder produced by the wet process is low, and it is still necessary to carry out electrolytic refining to become the final product; The slag, slag, lead slag, etc. are still a mixed primary product mainly composed of a metal and a chloride, and contain high silver, which is difficult to form a product in a wet process; 3 requires a large amount of , a variety of chemical raw materials; 4 more processes, large amount of intermediate solution, gold and silver slag and valuable metal compound slag variety; 5 more varieties of equipment, high anti-corrosion requirements, high maintenance and renewal costs; 6 still have environmental pollution The problem is that there are many waste gas and waste water, and the arsenic-containing waste residue needs to be stored. 7 The direct yield index of gold and silver is lower than expected; 8 the adaptability to raw materials is poor, such as the high demand for gold and silver in lead anode mud.
For example, wet processing of lead anode mud requires about 4.4 of raw materials, of which 2.8t of hydrochloric acid, 0.7t of salt, 0.5t of liquid ammonia, 0.2t of ammonium bicarbonate, 60kg of hydrazine hydrate, etc., and calcium carbonate 1.2 and water 28. The product still needs to be smelted and electrolytically processed to obtain the final product, which requires about 1 000 kW*h, as well as steam and filter cloth. In general, the processing cost of lead anode mud is relatively high.
According to some sources, if the wet process can make a breakthrough in stabilizing the quality of gold and silver, and the valuable elements such as bismuth can be produced in ready-to-use finished products, the wet process will have universal conditions, but still More difficult.
2.2 Wet method of the lead anode mud - fire process generally the wet method - fire process is also classified into the wet process, or the wet process - fire process. The main point of the process is the controlled chlorination of lead anode mud by bismuth metal, silver chloride base de-lead-melting, silver anode plate electrolysis, and silver electrolysis anode mud extraction of gold. Some domestic smelters have used this process to technically reform or construct a new production line for the original lead anode slime process. It has been reported that the process is suitable for anode mud with low gold content.
The key process of the process is controlled chlorination and base conversion. Controlled chlorination is to remove impurities and lead in the lead anode mud, so that gold and silver are enriched. The gold and silver enrichment in this process are all more than 3 times, and the leaching rate of main impurities of bismuth, antimony and copper can reach 97% or more, achieving the effect of one-step impurity removal. The alkali conversion is to convert silver chloride in the leaching slag into silver oxide, and perform fire smelting and oxidative refining on the silver oxide to obtain a crude silver anode plate. The base metal in the solution is recovered as a semi-finished product by a stepwise hydrolysis precipitation method or the like.
Controlled chlorination requires that the anode mud has sufficient oxidation degree. The design requires that the lead anode mud must undergo natural oxidation for more than 15 days. The anode mud with insufficient oxidation will increase the reaction temperature when the chlorine is passed, the solubility of silver will increase, and the selection of equipment materials will be more difficult. The residual silicate in the anode mud is more, when the lead anode mud is abrasived. It will increase the corrosion of the ball mill; excessive silicic acid and animal glue in the anode mud will cause a large amount of bubbles when leaching, making filtration difficult.
The particle size of the raw material also has an effect on the controlled chlorination. The lead anode mud will agglomerate after natural oxidation. In order to obtain a higher leaching rate, the lead anode mud must pass through the abrasive to make the particle size of about 250)m, and the ideal leaching rate can be obtained.
The reduction potential of chlorination directly affects the recovery of gold and silver. The potential is lower than 400mV, the impurity leaching is incomplete; the potential is higher than 450mV, and the loss of gold and silver is increased. The process potential is required to be stable, and finally the potential is stabilized at 420-450 mV for 1 h. The degree of conversion of the silver chloride-containing leaching slag will directly affect the smelting condition and the recovery rate of silver. The main control conditions of the alkali conversion process are the addition of alkali amount and temperature, and the addition of alkali should be completed once. The degree of complete conversion of the base can be judged from the color of the conversion slag.
There are many types of equipment required for the wet-fire process, high corrosion resistance requirements, and large maintenance workload; both wet process equipment and fire smelting equipment are required. There are ball mills or rod mills, filter press pumps, reaction tanks and storage tanks, filters, etc., as well as a large number of instruments, a large number of pipes and valves. The silver oxide after alkali conversion still needs to be smelted and oxidized and refined by a converter to obtain a qualified crude silver anode plate.
It is then transferred to a conventional electrolysis process to produce qualified gold and silver products.
It is said that the direct yield of gold and silver in this process is about 102 higher than that of the traditional fire process, and the recovery rate of leaching of bismuth, antimony and copper is also high. However, the one-time investment, reagent consumption, labor quota, and equipment maintenance are all larger than the traditional fire method, the total cost is relatively high, and the operating environment needs to be improved.
The process is economically superior to the pyrotechnic process, and the output of the slag, slag, and copper slag can at least offset the consumption of the portion of the fire process, rather than being sold as an intermediate product. However, it is still technically difficult to make 最终, 铋, etc. form the final product in the process.
2.3 Fire method of lead anode mud - electrolytic refining process The conventional method of lead anode mud metallurgy is fire method smelting-oxidation refining-electrolysis method. For selenium and niobium-containing lead anodes, the selenium and niobium are usually removed before the smelting process, and the copper is also included when the copper is high. The precious lead produced by smelting is subjected to drum air oxidation refining to obtain gold and silver alloy, and the silver grade is above 962. Silver and gold products are obtained by electrolytic refining.
With the development of smelting technology, lead anode mud, or copper and lead anode mud mixture reduction smelting, generally use converter or electric furnace, but also use small open hearth furnace. In addition to electric furnaces, heavy fuel or diesel fuel is used for fuel, and gas can be used in places where conditions permit. For the precious lead alloy produced by smelting, the total amount of silver should generally be above 30%~40%. The lead-free silver furnace is smelted, and the converter is generally used, and the small open hearth furnace and the reverberatory furnace are less used.
The smelting-oxidation refining technology of anode slime including lead anode mud and the technology of dust collection and soot treatment have been greatly developed. Oxygen-rich smelting technology and molten pool smelting technology, bottom-blowing and top-blowing converter technology, and new electrolytic refining technology have been applied in production and achieved great results.
Electric furnace smelting of anode mud 12. In order to improve the direct yield of gold and silver, reduce the intermediate products, shorten the working hours and reduce the backlog of liquidity, the Japanese mining company Hitachi smelter changed to leaching after de-coppering by electric furnace smelting anode mud in 1967. Slag. In 1968, the lead was smelted in an oxidizing furnace, and the crude silver produced was re-smelted into a silver furnace for refining.
In the initial stage of electric furnace production, the operating conditions of the original smelting furnace were followed, and the amount of matte and slag to be returned for treatment was large, and the lead oxide produced by the oxidizing furnace was returned to a large amount of gold and silver raw materials. In order to reduce the slag containing gold, silver and reduce the output of intermediate products, in December 1969, the new electric furnace ingredients were replaced. The main intermediate products to be returned from the electric furnace to the silver furnace are reduced from 6 to 3, and the gold and silver contents of various intermediate products are greatly reduced.
The recovery rates of gold and silver in the lead of electric furnace were 98.64% and 97.36%, respectively. The distribution ratios of gold and silver in slag were 0.64% and 1.36%, respectively. The distribution rates in soot were 0.08% and 0.58%, respectively. At the time, the total recovery rates of gold and silver were 99.36% and 99.30%, respectively. It can be seen that the fire treatment process also has high gold and silver yields and total recovery rates.
The test and production practice after improving the electric furnace batching proves that the advantages of using the new electric furnace ingredients are as follows: (1) Since the reducing agent is reduced, most of the lead in the leaching residue and the lead oxide enters the slag, so that the fluidity of the slag becomes good; 2 almost no formation of matte; 3 reduced the lead content in the precious lead of the electric furnace, gold and silver are enriched, thereby increasing the direct yield; 4 reducing the number of intermediate products, reducing the gold and silver content. These indicate that the improved electric furnace and its oxidizing furnace smelting precious lead have achieved remarkable effects in anode mud treatment.
The anode mud and the flux are simultaneously added by the mechanical ore feeder. After the roasting process for 12 hours, the amount of heavy oil combustion is increased and transferred to the smelting process. After the smelting time 101, the slag containing 40% and 50% of the lead is placed in a steamer, conveyed by a forklift, and then cooled to a slag block to be sent to a lead smelting workshop. The precious lead is also put into the steamed buns, and the precious lead is poured into the silver furnace with a 5t electric hoist and an electric tilt loader.
The silver furnace is a rotary furnace with internal heating by heavy oil. The outer diameter is 2.3m and the length is 3.0m. The chrome-magnesia brick is lined. The soda ash and sodium nitrate pass through the movable flue on the flue side, and are transported into the silver furnace through the air flow of the stainless steel tube, and the oxidation reaction is forcibly performed, and the inclined rotary kiln can continuously discharge the soda slag. The oxidation reaction time is about 20h. The biggest reason for the oxidizing refining time is greatly shortened is that the plant can use 0280% oxygen in the oxygen station, and the stainless steel tube with high alumina coating is used for stirring and spraying in the molten pool, and the oxidation refining efficiency is remarkable. improve. The refining end point is judged by rapidly analyzing the copper in the crude silver, and then the crude silver is cast into a large silver anode plate. Each anode plate is about to be cast on a silver furnace, and the oxygen-rich refining and bismuth recovery of the lead-anode mud lead in the monthly production of silver anode plate 14. Nissan of Japan's fine warehouse lead refinery The electric lead is 1800t, the crude silver is 10.2t, the electric sputum is 5.5t, and the antimony trioxide is 25t. The lead anode mud is washed and dehydrated by a centrifuge, and then smelted and reduced into noble lead in the reduction furnace. The precious lead is subjected to arsenic removal treatment in a refining pot, and then volatilized in a volatilization furnace, and the soot is made into cerium oxide. The lead-free lead is melted in an oxidizing furnace, and the ash is blown by the oxygen produced by the oxygen generator, and the lead and the bismuth are separately oxidized and released separately.
The lead oxide is returned to the blast furnace, and the cerium oxide is used as the raw material of the electric sputum, and then further refined, and the grade is determined, and then the crude silver anode plate is cast and sent to the Naoshima smelting plant for electrolysis. Oxidative refining using oxygen enrichment increases processing capacity. Beginning in July 1992, the lead electrolysis anode mud purchased at the Naoshima Smelter, the treatment volume of lead anode mud increased by about one time.
The bottom blowing oxygen converter treats the precious metal material. 15. The cerium oxide is reduced, refined, and cast into a rough anode by a reduction furnace, and electrolytically refined with a fluorosilicic acid electrolyte. The plate was changed once in 20~30d, and the obtained cathode was melted in a special pot and refined into four 9-purity electric sputum.
Bottom Blowing Oxygen Converter (BB0C) is a kind of converting furnace for the processing of precious metal-containing materials developed by British Refining Metal Company of MIM Group of Australia. It consists of furnace body, spray gun, hood, bracket and tilting device. The top of the top of the furnace is equipped with a burner, which uses natural gas, diesel oil or the like as a fuel for melting materials and the like.
Oxygen is injected into the melt from the bottom of the melt through an lance. The oxygen lance is a consumable spray gun protected by nitrogen. It is made of stainless steel pipe and inserted into the furnace through the refractory material of the furnace bottom. When used, the head of the spray gun is kept higher than the refractory material. The spray gun is equipped with a hydraulic automatic jacking device. When the spray gun head is partially consumed during the blowing, the spray gun will automatically push in, and the moving distance is 5 ~ 10mm each time. A thermocouple is installed in the gun to measure the consumption of the spray gun, which is measured according to the thermocouple. The temperature determines whether the gun is pushed up. The top hood is fixed on the mouth of the furnace and the sealing effect is good.
BBOC technology has been transferred to 10 companies including the United States, India, South Africa, Japan, and South Korea for the treatment of silver-zinc shells, copper anode mud or lead anode mud. Since oxygen is sprayed from the bottom of the furnace to the molten pool, the reaction speed can be greatly improved, the oxygen utilization rate and thermal efficiency are improved, and the materials are well adapted. Can produce Au+Ag! 99% of products. The BBOC method has the following advantages over the traditional ash blowing method: 1 the reaction speed is 15-20 times higher, the reaction vessel is greatly reduced, thereby reducing the backlog of precious metals, shortening the smelting cycle and saving manpower; 2 process strengthening, process self-heating, saving A large amount of fuel, fuel consumption is only 20% of the traditional ash blowing method; 3 due to oxygen supply from the bottom of the furnace, the thickness of the slag layer does not affect the oxygen transfer, improve the separation of metal and slag, improve the recovery rate of precious metals, avoid the slag The thickness of the layer affects the control of the process; 4 the method of immersing oxygen is used to make the oxygen utilization rate close to 100%; 5 due to the enhanced smelting, the amount of smoke is small, and the hood is well sealed, which greatly improves the sanitary condition. It reduces the consumption of flue gas treatment equipment and electricity; 6 products can be directly cast into anode plates without passing through tundish or holding furnace.
Japan's Niihama refinery precious metal operation replaces the traditional ash blowing process with BBOC process. Its BBOC type ash blowing furnace has an effective volume of 0.36m3, the fuel is liquefied petroleum gas, and the spray gun is double-casing type, and the oxygen utilization rate is increased from 8% to 85%. Each furnace melts 4.5t of precious lead, which is 1.5 times that of the old furnace, and the production efficiency is doubled; the smoke rate is reduced from 15% to the buckle%; the slag contains high enthalpy, which improves the recovery rate of strontium.
MIM company personnel have gone to some copper and lead smelters in China to carry out technical exchanges, promote BBOC technology, and make a preliminary discussion on the use of BBOC technology to transform existing ash-blowing furnaces in a factory. The calculation results show that the cost of savings and efficiency can be quickly recovered. Technical transformation investment. The BBOC process has been improved day by day. It is attractive to factories that still use the fire process to treat anode slime in China, especially for manufacturers with convenient oxygen supply.
Caldo converter treatment of anode mud technology 16. Caldo furnace is a top-blown converter TBRC with oxygen-rich spray gun, Politon uses Caldo converter to smelt copper and lead, and is now used in Longskar precious metal smelters. The Caldo furnace for precious metal smelting has a small volume, and the furnace is equipped with a material nozzle, including a combustion lance and a blowing lance. Several reactions in several stages, such as smelting, slag reduction, blowing and refining, are carried out in the same furnace. The furnace is completely sealed to avoid smoke escape. The technical features are: short operating time, low metal backlog, low energy consumption, small amount of flue gas, high recovery rate and good operating environment.
The prepreg anode mud produced by the copper refinery is first dried, mixed with the return material and flux, and then added to the Caldo converter. The furnace heats and smelts the material during the rotation to produce a silver alloy and slag. This is the first step of the operation.
The second step is to add a coke reduction to reduce the silver content of the slag to less than 0.3%, and then release the slag. The slag is injected into the slag package, and the metallic silver contained in the slag is deposited on the bottom of the slag package after the slag is cooled. The Brokk pulse crusher is used to crush the slag, and the separated silver particles are “returned to the Caldo furnace, and the slag is sent to the copper smelting plant for recycling. The remaining various slag and intermediate products are recycled in the precious metal plant.
The third step is blowing and refining. Oxygen-enriched air is blown directly onto the surface of the rough metal by a spray gun. Selenium, lead and copper are oxidized. Selenium dioxide is volatilized and absorbed in the venturi of the purified flue gas. Lead and copper enter the blowing during the Caldo furnace blowing. Slag.
After refining, the impurity content of the gold-silver alloy is very low, and it is cast into a gold-silver anode plate by a casting machine.
Three-stage treatment of low-grade anode mud 17. The original Shenyang smelter comprehensively recovers gold and silver from copper and lead anode mud, using the traditional two-stage smelting process. In response to the problem of the two-stage method, a blowing furnace was added between the melting furnace and the refining furnace. In the blowing furnace, the low-grade precious lead is concentrated into high-grade precious lead and then transferred to the refining furnace for deep oxidative refining. The whole process of gold and silver smelting is divided into anode smelting reduction smelting and low-grade precious lead primary. Oxidation blowing and high-grade precious lead deep oxidation refining three stages, so it is called three-stage melting method. The low-grade copper and lead anode mud can be treated monthly for about 200t. Compared with the two-stage method, the melting capacity of the melting furnace and the refining furnace is increased by 140% and 46%, respectively, and the capacity of the original melting furnace is 4.29t/furnace* ( !); The comprehensive production capacity of gold and silver increased by more than 50%, the enrichment recovery rate of lanthanum and cerium increased by 8% and 7%, respectively, and the heavy oil consumption decreased by 24%. This is a partial improvement of the traditional process.
(7) Electric furnace smelting of sorghum low silver anode mud 18. Composition of sorghum anode mud): Bi30~40, Pb20~33, Sb4~7, Cu2~6, Ag0.2~0.8. The original process uses oxidative roasting After ball milling, chlorination (hydrochloric acid and chlorine F leaching, bismuth oxychloride produced by hydrolysis of the leaching solution is dried in a reverberatory furnace and then subjected to electric arc furnace reduction and smelting to produce coarse enthalpy. Then a series of fire removal methods are performed on the rough enthalpy. After the silver is fine, the process has a long production cycle and low recovery rate.
The improved new process cancels the chlorinated leaching part, and the sorghum anode mud is dried by the reverberatory furnace and H2O10%) directly reduced by the electric arc furnace to produce coarse é“‹, which has a mass fraction of %): Bi silver and a series of Produce fine after the impurity removal operation.
After the improved process, the straightening yield increased from 64.06% to 69.58%, and the hydrazine recovery rate reached 76.75%, which was basically the same. Each 1t of refined sputum can save 10t of hydrochloric acid, 526kg of chlorine, and 2900kW*h of electricity. It can be seen that the amount of chemical reagents is greatly reduced or no longer used.
(8) Improvement of fire refining of Gaoqigui lead 19. The lead lanthanum content of lead smelting mud in Shandong Yimeng smelting plant is relatively high, its composition%): Au 0.14. The high lead content of noble lead is too high for fire refining and electrolytic refining A series of problems, such as the fire method refining furnace is too long, ton of alloys need to use 136h, diesel consumption of 5~6t; and the output of silver alloy plate containing bismuth is still greater than 4.2 times the allowable value; electrolyte depletion is fast, need Frequently replenishing new liquid; the quality of silver powder is poor, the silver grade is only 99.8%c; the amount of black gold powder is large, and the silver content is as high as 50%~70%, which increases the difficulty of recovering gold.
In order to reduce the strontium content of the crude silver alloy, in the improved operation, the pre-stage furnace temperature is controlled at 850~9000C oxidized lead slag. When a thin layer of oily slag appears on the surface of the alloy melt in the molten pool, it indicates that The lead slag phase is coming to an end. Then step down or increase the temperature slightly, and blow the oxidation to make the first slag and the second slag. When the amount of slag in the furnace is very small, and the alloy contains silver grade of more than 85%, it can be heated to 1000~11000C. When the alloy contains more than 97% of silver, the furnace temperature is raised to 12000 C, and a small amount of potassium nitrate is added for refining. When the Au+Ag content in the coarse silver alloy is greater than 98%, the furnace temperature is lowered to 1000-11000 C, and the alloy plate is cast.
The main effect of the process improvement is that the average furnace time is shortened by nearly 9 hours, the average yield of silver refining is increased by 2.63%, the unit consumption of tons of alloy diesel is reduced by 333kg, and the content of rhodium in the coarse silver alloy sheet is reduced to less than 0.3%. The quality of electrolytic silver powder is good. The direct yield of electrolysis is increased by 1.86%; 90%~97% of niobium in precious lead is enriched in cerium oxide slag, which is beneficial to the recovery of hydrazine.
3 lead anode mud electrothermal continuous melting technical program In general, lead anode mud and copper anode mud, silver grade is basically close, but lead anode mud gold and copper content is low, lead grade is higher, and 锑, 铋The content is much higher, and the content of selenium and tellurium is low. As mentioned above, after about ten days of storage, the lead anode mud has a water content of about 10%, and the heavy ferrous metal is basically in an oxide state.
The value of lead anode mud is lower than that of copper anode mud; but the wet treatment also requires that the amount of chemical raw materials required for lead anode mud is much higher than that of copper anode mud, and the complete separation of lead, bismuth and bismuth chloride and its further treatment It is more difficult to become a single product. In the selection of lead anode mud treatment technology, we should make full use of the characteristics of lead anode mud, improve and improve the recycling technology of gold, silver and valuable metals in lead anode mud.
In general, lead anode mud is a material that is well suited for processing by fire smelting techniques. This includes: 1 the composition of the lead anode mud and the presence of the element indicate that it is easy to be smelted by fire, the preparation and the ingredients are simple, the enrichment, reduction, slagging, volatilization of different elements and the process and degree of the difference are obvious; 2 smelting Oxidation and refining of precious lead only consumes heat and oxygen in the air, and requires fewer varieties and quantities of chemical reagents. 3 The application of oxygen-enriched injection and molten pool smelting technology and control technology greatly improves production efficiency and equipment efficiency. Conducive to eliminating pollution and improving the production environment; 4 adaptability to raw materials and scale, 5 low production cost; 6 silver alloy plate electrolysis is beneficial to ensure the quality of silver and gold products; 7 recycling of valuable elements in slag and soot The chloride is convenient, the intermediate product can be returned to the main process or treated separately; 8 for the difference of lead anode mud composition, different process combinations and corresponding operating conditions can be used before and after smelting.
In order to facilitate the comprehensive recovery of lead anode mud, this paper proposes a lead anode mud electrothermal continuous melting technology scheme, combined with the practice and development of lead anode mud smelting technology, the technical points are briefly described as follows: lead anode mud is naturally dried and oxidized for electric heating Continuous smelting, furnace capacity greater than 12t / (m2, d), 1kW, h can melt lead anode mud 1 ~ 1.5kg. Daily treatment 1t lead anode mud, the bed area is 0.14m2. The furnace has precious lead and oxidation The molten pool formed by the slag controls a certain layering height, and feeds and discharges at regular intervals to realize the continuation of the smelting process. The melting furnace has high efficiency and good environmental protection conditions.
0.013%, the direct yield of silver is greater than 98%, the silver enrichment ratio is 3-4. The distribution ratio of other elements in precious lead is %): Bi is close to 3, most of arsenic enters the dust, most of the strontium enters the slag, and a large amount of lead Also involved in slagging.
The precious lead oxidizing refining adopts the molten pool smelting technology to carry out the oxidative spraying in the molten pool, and the oxygen-enriched blowing is used in the condition to improve the oxidation efficiency and the equipment efficiency. If the lead is 330kg per furnace, the volume of precious lead is about 0.033m3. The effective volume of the required refining furnace is relatively small, the furnace is about 0.30m, the height is about 0.75m. The oxygen utilization rate is higher than 85%. The degree of oxidative blowing is selected according to the composition characteristics of the lead anode mud and the requirements of the product. The precious lead can be directly oxidized and refined into a crude silver anode plate, and gold and silver products can be obtained by electrolysis. Lead and lead are enriched and recovered in by-products. Or the production of lead-bismuth alloy by acid-soluble step-by-step precipitation and conversion treatment, respectively, can obtain silver oxide and bismuth oxychloride until the final product is obtained.
If there is a change in the data of page 44), there is a problem with the scale.
3.2 Execution unit failure and processing When the proportional valve fails, the casting package does not work properly or does not work. This is also the case when the return solenoid valve fails. Check if the input signal of the proportional valve is normal and check the circuit of the proportional valve itself. The electrical components of the proportional valve work at a higher temperature. Pay attention to the temperature and check whether the output signal is normal. Also, check if the oil line is clogged.
3.3 control unit failure and processing components, faults can be divided into hardware and software. When the hardware fails, the casting cannot be performed; the software failure is generally inappropriate for the casting curve and affects the accuracy of the anode copper.
When the hardware fails, the hardware should be replaced. The casting curve should be adjusted according to the following principles: adjust the setting value of the casting package according to the amount of bonded copper water in the casting package, adjust the casting speed setting value of the casting package according to the temperature of the casting copper water, and adjust the pouring control voltage according to the casting curve, etc. For example, the casting pouring speed Vbp, the intermediate pouring speed Vmp, the ending speed Vep, and the respective flow rates Fmax, Fmp, and the like. 3.4 Other reasons The material selection and operation of the casting machine also affect the quality of the anode plate, such as (Continued from page 11). The technical solution has low investment and production cost, small equipment specifications, high efficiency and easy maintenance.
As described above, the technical solution has good feasibility, basically has the basis of successful application, can effectively realize the comprehensive utilization of lead anode mud, and can currently carry out small-scale trial production, and has a good prospect for industrial production. , Khao Li Weifeng, Zhao Zhanchao. Summary of wet treatment of lead anode mud heavy smelting, Li Weifeng, Jiang Lihua, Yang Anguo, Sun Zhongsen. Improvement of lead anode mud wet process research Tan Guangqing. New process test and production practice of lead anode mud treatment I. Heavy Metal Section Zhang Yu. Anode mud wet treatment process and application I. Hunan Nonferrous Metals, 1992, Lei Xingguo. Discussion on the choice of lead mud treatment process I. Non-ferrous metal smelting part), Gong Guiying. Hydrochloric acid leaching method to treat lead anode mud to extract gold and silver I. Non-ferrous metal Yi Wu Keli. Wet pretreatment with low arsenic and lead anode mud I. Selection and masonry of cast refractory materials for non-ferrous metal refining parts, cooling water volume selection for casting molds, selection of spray materials, etc. Inappropriate spray materials cause bubbles and flash on the anode plate. In addition, the condition of the thimble and the mold position, the sulfur content in the copper water, the oxygen content, the installation level of the casting mold, the copper water temperature, and the appropriate mold temperature all affect the quality of the anode. Controlling these links is beneficial to improve the quality of the anode plate.
4 Conclusion By strengthening the prevention and protection of key electrical equipment components, such as regularly checking the casting proportional valve, weighing sensor; regularly replacing the cutting edge of the detection unit, the tool holder; regularly performing the electronic scale verification; etc.; and adjusting the setting of the casting curve in a timely manner, The disc casting machine is now operating normally, the quality of the produced anode plate is gradually improved, and the pass rate of the anode plate is increased from 70A to over 95A. The number of system failures has decreased year by year, and the processing at the time of failure is also faster and more accurate than before. In view of the relatively high number of electronic scale failures, Jinlong Copper Co., Ltd. has introduced the new electronic scale device newly developed by Outokumpu of Finland to improve the system performance of the entire disc casting machine, and the quality of the anode plate will be further improved. . , Kao Peng Rongqiu. Handbook of Nonferrous Metals Extraction Metallurgy M. Beijing: Metallurgical Industry Press, Chen Boshi. Automatic Control System M. Beijing: Mechanical Industry Press, 1986. Inner Mongolia Metallurgical Institute. Gold-containing heavy sand aqueous phase chlorination liquid-liquid extraction gold extraction I. Non-ferrous metal smelting), 1976, 3): Seal four.
Yang Maocai. Progress in the technology of comprehensive utilization of lead anode mud I. Precious metals, 1998, 19 Xu Qingxin. Summary of wet anode treatment design of lead anode mud I. Nonferrous smelting, 1999, 28 Deng Feng translation. New precious metal refinery I. Sun Wei of Nolanda Mining Company CC3 Branch. Gold and silver metallurgy. Beijing: Metallurgical Industry Press, 1986, 286-289. translated by Wang Ruimei. Precious metal smelting at Naoshima Smelter I. Nonferrous smelting, 1997, 1): Xu Yuru translated. Lead smelting in the Shougang smelter I. Nonferrous smelting, 1997, (2): 16-Shi Xueqian. Treatment of precious metal-containing materials with a bottom-blowing oxygen converter I. Non-ferrous smelting, translated by Wang Shikun. The new precious metal smelting plant of the Polish Copper Mine Mining and Metallurgy Co., Ltd. I. Nonferrous Liu Hongwei. Study and practice of three-stage treatment of low-grade anode slime I. Non-ferrous ore Ruhr. New technology for sorghum anode slimming. I. Nonferrous Metals, 998, 5): Wang Jianzhi. Gao Qigui lead fire refining practice I. Non-ferrous metal refining part),
Baby accessory
Breast pump, bell toy, door cabinet, drawer lock, nasal aspirator, baby scissor, medicine feeder, baby brush, baby comb, cotton swab, bath sponge, thermometer, plastic tweezer are all in baby accessory series. You may find many baby related tools and other necessities here, important for baby daily use.
Howawa is top baby products manufacturer in China, provide OEM & ODM service, all products are made of safe and food grade material, get CE and ISO9001, pass European tests. Howawa cares baby as own baby, we try our best to provide best products, we keep developing ourselves and designing new items to enjoy baby the newest.
Baby Accessories,Baby Care Accessory,Infant Accessory,Baby Safety Lock
​Taizhou Howawa Baby Products Co., Ltd. , https://www.howawa.com