Valuable metal enrichment method based on multi-source metallurgical solid waste sintering

Abstract

The invention belongs to the technical field of solid waste recycling, and provides a valuable metal enrichment method based on multi-source metallurgical solid waste sintering, which specifically comprises the steps of primary mixing of a bottom layer material, secondary mixing of the bottom layer material, primary mixing of a top layer material, secondary mixing of the top layer material, material distribution in batches, sintering enrichment and the like. Through reasonable compatibility of specific multi-source metallurgical solid waste, a two-stage mixing process of selecting powder from copper slag and preferentially combining copper tailings and gold tailings with chlorides, and a batch distribution mode, valuable metals such as gold, silver and titanium are promoted to generate metal chlorides which are low in melting point and easy to gasify in the sintering process, gasification separation of the valuable metals and other materials is achieved, and the production efficiency is improved. And the subsequent flue gas is naturally cooled, and dust is removed, so that the material containing the valuable metal forms an ash material, and finally sintered ore capable of being directly used as a blast furnace material and high-value valuable metal enriched powder taking gold, silver, titanium and the like as main components are synchronously obtained, so that the dual targets of solid waste co-processing and high-value resource recovery are achieved.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical solid waste resource utilization technology, specifically involving a method for enriching valuable metals based on the sintering of multi-source metallurgical solid waste, applicable to the co-processing of various metallurgical solid wastes such as copper slag, copper tailings, gold tailings, zinc-containing tailings, zinc-containing ash, and gas ash. Background Technology

[0002] Copper slag, copper tailings, gold tailings, zinc-containing tailings, and gas ash are solid wastes generated during the metallurgical industry. These solid wastes are conventionally used as roadbed materials or backfill materials, or directly landfilled. However, since these solid wastes actually contain relatively large amounts of valuable metals such as iron, copper, zinc, gold, silver, titanium, and lead, using them as roadbed materials or directly stockpiling or landfilling them would not only occupy a large amount of land resources, but could also lead to heavy metal leakage, polluting the soil, groundwater, and surrounding ecological environment. This would not only waste the valuable metals, but also turn them into harmful elements for the environment.

[0003] Currently, there are some methods for resource recovery of this type of metal slag solid waste. Copper slag and copper tailings are currently processed using flotation and other processes to extract residual copper, iron, and other materials; gold tailings are stabilized and then used to prepare autoclaved aerated concrete blocks; zinc-containing tailings are recovered using a rotary kiln volatilization method to recover secondary zinc oxide, and the residue after zinc removal can be used as sintering raw material or in building material production; gas ash is mainly recovered as a sintering auxiliary material. However, these recovery methods are either complex and costly, or have relatively low recovery rates, and they can only target one or two types of solid waste, failing to achieve comprehensive recycling and reuse of multi-source metallurgical solid waste.

[0004] Sintering is the mainstream technology for preparing sintered ore. Its core process involves crushing iron ore and placing it on a sintering machine trolley for high-temperature sintering to form sintered ore with specified particle size and strength. This sintered ore can effectively remove some harmful elements such as sulfur, arsenic, potassium, and sodium. The resulting porous sintered ore can be directly used as raw material for blast furnace smelting, making it a crucial link between raw material pretreatment and blast furnace ironmaking in the iron and steel smelting process. The core steps of the sintering method include raw material preparation, batching and mixing, charging and ignition, high-temperature sintering, and finished product processing. The high-temperature sintering process softens and melts the minerals in the mixture, causing them to agglomerate into blocks. Simultaneously, it removes some harmful elements and constructs a porous structure, ensuring efficient subsequent blast furnace smelting. Currently, industrial solid waste (such as gas ash and sludge) is also added during the sintering process. This type of solid waste is a secondary waste generated from iron and steel production, containing certain iron elements and valuable precious metals. However, it is currently only used as an auxiliary material, with an addition ratio not exceeding 20%, and large-scale, high-value-added recycling of solid waste has not yet been achieved. If all industrial solid waste is used as the main raw material for sintering, the valuable metals in it will re-enter the metal smelting process. Even worse, due to the enrichment of some elements, it will cause defects such as poor blast furnace operation.

[0005] Therefore, developing a method that enables the synergistic treatment of multi-source metallurgical solid waste, efficient enrichment of valuable metals, and is easy to implement industrially has become a pressing technical problem to be solved in the field of metallurgical solid waste resource utilization. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for enriching valuable metals based on the sintering of multi-source metallurgical solid waste. The core of this method is to rationally design the ratio of bottom and top materials, accurately add chloride additives, and optimize the mixing and distribution processes. High-temperature sintering allows chlorides to react with valuable metals such as gold, silver, and titanium in the solid waste to generate low-melting-point, easily gasified metal chlorides. During the sintering process, the valuable metals are effectively separated from other materials by gasification. After flue gas cooling and dust removal, high-value valuable metal enriched powder is obtained. At the same time, qualified sintered ore by-products that can be directly used as blast furnace feed are also produced. This method realizes the synergistic sintering treatment of multi-source metallurgical solid waste, improves the resource utilization rate of solid waste, reduces environmental pollution risks, and balances environmental and economic benefits.

[0007] The present invention is achieved through the following technical solution: A method for enriching valuable metals based on sintering of multi-source metallurgical solid waste includes the following steps: I. Bottom Material Mixing: 38-46 parts by weight of copper slag powder, 1.5-1.9 parts by weight of calcium chloride, 0.10-0.15 parts by weight of magnesium chloride, 0.05-0.12 parts by weight of ferric chloride, 0.10-0.20 parts by weight of calcium oxide, 3-9 parts by weight of copper tailings, 20-33 parts by weight of gold tailings, 1.2-3.2 parts by weight of carbon fuel, and 0.6-2.6 parts by weight of lime are mixed in a mixer, and 2.5-4.5 parts by weight of water are added during the mixing process. The mixture is continuously mixed for 1-2 minutes to obtain the bottom material mixing.

[0008] II. Second mixing of bottom layer material: The obtained bottom layer first mixture is placed into a granulator and mixed for 2-4 minutes while continuously adding 3-6 parts by weight of water to obtain the second bottom layer mixture.

[0009] III. Top layer material mixing: Mix 12-21 parts by weight of zinc-containing tailings, 5-12 parts by weight of zinc-containing ash, 5-10 parts by weight of gas ash, 0.6-1.6 parts by weight of carbon fuel and 0.3-1.3 parts by weight of lime in a mixer, and add 1.2-2.1 parts by weight of water during the mixing process, and continue mixing for 1-2 minutes to obtain the top layer material mixing.

[0010] IV. Second mixing of top layer material: The obtained top layer first mixture is placed into a granulator and mixed for 1 to 2 minutes while continuously adding 1.5 to 3 parts by weight of water to obtain the second top layer mixture.

[0011] V. Batch material distribution: A base material is laid on the sintering machine trolley. Two material distributors are set up in the direction of the sintering machine trolley's forward movement. The bottom layer of mixed material is distributed through the rear material distributor, and the top layer of mixed material is distributed through the front material distributor. As the sintering machine trolley moves forward, the bottom layer of mixed material is distributed on top of the base material, and the top layer of mixed material is distributed on top of the bottom layer of mixed material. The total thickness of the material layer is 500~800mm.

[0012] VI. Sintering and Enrichment: The sintering machine used in step V (material feeding) is ignited and sintered, and a top-down exhaust fan is simultaneously started. During the high-temperature sintering process, the chloride additives such as calcium chloride, magnesium chloride, and ferric chloride in the bottom layer react fully with valuable metals such as gold, silver, and titanium in the solid waste to generate metal chlorides with low melting points and easy gasification. These metal chlorides are then carried into the flue gas by the exhaust airflow. After continuous sintering, the remaining material cools and solidifies to form sintered ore with qualified iron content that can be directly used as blast furnace feed. At the same time, the sintering flue gas containing metal chlorides is continuously discharged into the main flue for cooling through the exhaust fan. During the cooling process, the gaseous metal chlorides cool and condense, combining with the dust in the flue gas to form ash containing high-value metals. The cooled flue gas is then discharged to the dust collector, where the cooled dust is collected to obtain high-value metal enriched powder with gold, silver, titanium, and other valuable metals as the main components.

[0013] Preferably, the carbon fuel is coke powder or anthracite powder; the lime material is one or more of quicklime, limestone, hydrated lime or dolomite.

[0014] Preferably, the lime, copper tailings and gold tailings in step (1) are all crushed before mixing, so that the particle size of the copper slag powder, calcium chloride, magnesium chloride, ferric chloride, calcium oxide, copper tailings, gold tailings, carbon fuel and lime are all less than 5 mm (where the particle size of lime, copper tailings and gold tailings is 1~4 mm, calcium chloride, magnesium chloride, ferric chloride, calcium oxide and copper slag powder are all 0.5~3 mm powder, and carbon fuel is powder with a particle size of less than 3 mm accounting for more than 90%).

[0015] Preferably, the lime and zinc-containing tailings in step (3) are crushed before mixing so that the particle size of the zinc-containing tailings, zinc-containing ash, gas ash, carbon fuel and lime are all below 4 mm (where the particle size of lime and zinc-containing tailings is 1~4 mm, the particle size of zinc-containing ash and gas ash is 0.5~3 mm powder, and the carbon fuel is powder with a particle size of less than 3 mm accounting for more than 90%). Preferably, in step V, the thickness of the bottom layer of the second mixture is 1.5 to 3.5 times that of the top layer of the second mixture.

[0016] Preferably, in step V, the sintering machine is a negative pressure belt-type exhaust sintering machine.

[0017] Preferably, in step VI, the ignition temperature for ignition sintering is 1050~1200℃, the exhaust velocity is 1.5~2.6m / s, the exhaust pressure in the main flue is 8~13kPa, and the temperature of the high-temperature combustion zone is 1360~1480℃.

[0018] Preferably, the moving speed of the sintering machine trolley is 1.2~2.0m / min.

[0019] Preferably, the sinter obtained in step VI has a drum strength of 70-78%, a drop strength of 85-90%, and a yield of 78-88%.

[0020] Preferably, the chemical composition of the valuable metal-enriched powder contains: TFe: 1.02~3.32 wt.%; Zn: 3.89~7.05 wt.%; K2O: 16.25~29.85 wt.%; Na2O: 11.06~18.21 wt.%; Au: 0.9~1.3 ppm; Ag: 150~180 ppm; Pb: 7.0~8.5 wt.%; Ti: 15.8~19.5 wt.%.

[0021] Preferably, in step VI, the mass of sinter obtained per ton of raw material is 0.9 to 0.99 tons (preferably 0.97 to 0.99 tons), and the mass of valuable metal-enriched powder obtained per ton of raw material is 0.01 to 0.1 tons (preferably 0.01 to 0.03 tons).

[0022] Solid wastes such as slag and ash have a very complex material composition with various coupled forms. Therefore, the composition is generally calculated based on oxides. For iron, the main element, it is generally calculated as total iron (T). Fe The calculation is performed in the form of (), which is not the actual form in which the material exists in the slag and ash.

[0023] Preferably, the copper slag powder contains T by mass percentage. Fe : 47.500~57.960wt.%, CaO: 0.950~2.070wt.%, MgO: 3.287~4.057wt.%, SiO2 : 9.700~19.334wt.%, K2O: 0.276~0.476wt.%, S: 0.010~0.052wt.%, Al2O3: 5. 710~7.276wt.%, P: 0.009~0.026wt.%, MnO: 0.295~0.621wt.%, TiO2: 0.665~ 0.942wt.%, Zn: 0.874~1.377wt.%, Au: 0.001~0.003ppm, Ag: 2.470~5.693ppm Industrial waste slag generated during pyrometallurgical copper smelting with Pb: 0.114~0.362 wt.%.

[0024] Preferably, the dust collector is a bag filter.

[0025] Preferably, the zinc-containing tailings contains T by weight percentage. Fe The residue remaining after smelting zinc concentrate, comprising: 47.380~54.855 wt.%, CaO: 9.785~11.592 wt.%, MgO: 4.141~5.392 wt.%, SiO2: 2.771~4.150 wt.%, Al2O3: 0.948~2.370 wt.%, MnO: 0.680~1.066 wt.%, P: 0.093~0.207 wt.%, S: 0.103~0.207 wt.%, TiO2: 0.103~0.331 wt.%, Zn: 4.965~6.189 wt.%, K2O: 0.103~0.321 wt.%, and Na2O: 1.051~2.391 wt.%.

[0026] Preferably, the copper tailings contain T by mass percentage. Fe: 36.860~44.100wt.%, CaO: 6.712~9.437wt.%, MgO: 0.834~1.970wt.%, SiO2: 5.054 ~7.801wt.%, P: 0.078~0.196wt.%, S: 2.929~4.596wt.%, Al2O3: 0.980~2.117wt.%, MnO: 0.495~1.235wt.%, TiO2: 0.107~0.608wt.%, Zn: 0.601~1.009wt.%, K2O: 2.454 ~3.900wt.%, Na2O: 0.097~0.304wt.%, Au: 0.126~0.931ppm, Ag: 18.624~33.222ppm Secondary tailings remaining after copper beneficiation of pyrometallurgical copper smelting slag with Pb: 1.261~2.940 wt.%

[0027] Preferably, the gold tailings contain T by weight percentage. Fe : 43.650~53.900wt.%, CaO: 2.503~3.900wt.%, MgO: 0.640~1.940wt.%, SiO2: 7.285 ~9.682wt.%, P: 0.029~0.088wt.%, S: 1.804~1.490wt.%, Al2O3: 1.950~3.087wt.%, MnO: 0.204~1.000wt.%, TiO2: 0.349~0.794wt.%, Zn: 0.611~1.029wt.%, K2O: 0.369 ~1.009wt.%, Na2O: 0.010~0.098wt.%, Au: 0.005~0.050ppm, Ag: 20.661~34.888ppm Solid waste generated during gold smelting with Pb: 0.078~0.245 wt.%.

[0028] Preferably, the zinc-containing ash contains T by weight percentage. FeZinc-containing solid waste generated during the iron and steel smelting process, comprising: 32.010~48.960 wt.%, Zn: 3.880~6.324 wt.%, SiO2: 4.375~7.324 wt.%, Al2O3: 4.860~6.171 wt.%, MgO: 3.550~5.059 wt.%, CaO: 2.532~4.090 wt.%, Na2O: 0.194~1.020 wt.%, TiO2: 0.417~0.928 wt.%, S: 0.689~0.928 wt.%, K2O: 0.126~0.867 wt.%, MnO: 0.107~0.694 wt.%, and P: 0.034~0.094 wt.%.

[0029] Preferably, the gas ash contains T by weight percentage. Fe Solid waste generated from blast furnace gas purification systems, comprising: 28.500~38.380 wt.%, SiO2: 6.184~7.252 wt.%, CaO: 3.430~6.919 wt.%, MgO: 3.610~4.949 wt.%, Al2O3: 2.480~5.060 wt.%, Zn: 1.007~3.151 wt.%, S: 0.770~1.525 wt.%, K2O: 0.504~1.061 wt.%, TiO2: 0.200~0.889 wt.%, MnO: 0.171~0.818 wt.%, and P: 0.040~0.103 wt.%.

[0030] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects: This invention involves mixing and granulating copper slag powder, copper tailings, and gold tailings rich in valuable metals such as gold, silver, and lead with specific proportions of calcium chloride, magnesium chloride, ferric chloride, calcium oxide, as well as fuel coal powder and lime. Because these solid wastes are rich in these valuable metals, they can strongly bind with chlorides, allowing these valuable metals to react more fully with the chlorides during sintering to form low-melting-point metal chlorides that enter the flue gas. Furthermore, because chlorides have a strong water-absorbing effect, this process... When materials are first mixed, they are more likely to form granulation nuclei. Then, during the second mixing and granulation, this material can form relatively large granules. By pre-distributing these materials, they can be more fully distributed at the bottom of the sintering machine trolley. The relatively higher temperature at the bottom facilitates the reaction and further enhances the separation of valuable metals. Furthermore, since the exhaust is from top to bottom, the reaction products from the bottom materials more easily enter the main flue, thus achieving precise and targeted recovery of valuable metals from these solid wastes. Zinc-containing tailings, zinc-containing ash, and gas ash contain elements such as gold, silver, and lead, as well as small amounts of chlorides (e.g., zinc chloride in zinc-containing ash, potassium chloride, sodium chloride, and zinc chloride in gas ash, and trace amounts of zinc chloride, basic zinc chloride, potassium chloride, and sodium chloride in zinc-containing tailings). These small amounts of chlorides will also react with valuable metals in the slag and ash during sintering and enter the flue gas. This invention employs a step-by-step mixing and distribution method based on the different properties of various solid wastes. It enables the specific addition of polychlorides to solid wastes with high-value metals, while solid wastes with relatively low-value metals are extracted using their own chlorides. This achieves refined and separate treatment, thereby maximizing the extraction of valuable metals from solid wastes while also producing sintered ore that meets the requirements. Utilizing the high-temperature reaction characteristics of chlorides with valuable metals, a differentiated ratio design for bottom and top materials is adopted. The bottom material is adapted to the occurrence characteristics of valuable metals such as copper, gold, silver, and titanium in copper slag, copper tailings, and gold tailings. Precise addition of chloride additives such as calcium chloride, magnesium chloride, and ferric chloride can efficiently promote the formation of metal chlorides with low melting points and easy gasification under high-temperature sintering conditions, achieving complete gasification separation of valuable metals from other materials. The top material is adapted to the occurrence characteristics of valuable metals such as zinc in zinc-containing tailings, zinc-containing ash, and gas ash. The ratio of carbon fuel and lime is optimized to ensure full volatilization of valuable metals. Combined with subsequent flue gas cooling and dust collection, it can not only efficiently enrich valuable metals, but also obtain high-value valuable metal enriched powder with gold, silver, and titanium as the main components. Compared with traditional single solid waste recycling methods, the recovery rate of valuable metals is significantly improved, and the added value of the products is greatly increased. At the same time, the quality of sintered ore is taken into account, achieving the dual benefits of "one process and two products".

[0031] This invention enables the synergistic treatment of multi-source metallurgical solid waste by separately mixing and distributing the waste according to its specific component characteristics. It rationally combines various metallurgical solid wastes, such as copper slag powder, copper tailings, gold tailings, zinc-containing tailings, zinc-containing ash, and gas ash, as sintering raw materials. This effectively solves the problems of difficult disposal and resource waste of single solid wastes, achieves solid waste reduction and resource utilization, reduces the environmental pollution risk caused by solid waste stockpiling, and meets the development needs of industrial solid waste resource utilization in the construction of "zero-waste cities". By employing a two-stage mixing process of "one mixing + two mixing" for the bottom material, adding an appropriate amount of water and controlling the mixing time, the uniformity and permeability of the bottom material can be improved (chlorides are highly hygroscopic and easily form large particles), ensuring that the chloride additives and valuable metals are in full contact and react completely. The top material also adopts a two-stage mixing process to ensure the looseness of the material layer and avoid the material layer from caking during sintering. The batch material distribution method makes the material layer structure uniform and the temperature field distribution during sintering reasonable, ensuring that the sintering reaction is sufficient. This not only yields sintered ore with qualified iron content that can be directly used as blast furnace feed, but also high-value enriched powder with valuable metals such as gold, silver, and titanium as the main components, achieving the resource utilization effect of "one to many", greatly increasing the added value of the product. At the same time, high-temperature sintering can degrade potentially harmful organic matter contained in solid waste, reducing the risk of secondary pollution.

[0032] This invention is simple to implement and easy to industrialize because it only uses existing sintering processes and changes the ingredients. The mixing, feeding, sintering and dust removal processes of this invention all use existing mature equipment, without the need for new complex equipment. The process parameters are clear and controllable, and the operation is simple, making it suitable for large-scale industrial application. In addition, the flue gas generated during the sintering process can reduce environmental pollution after cooling and dust removal, and the waste heat of the flue gas can be further recovered and utilized. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of the batch fabric of the present invention.

[0035] Figure 2 This is a physical image of the sintered ore obtained in Example 1 of the present invention.

[0036] Figure 3 This is a side view of the fabric feeder according to Embodiment 1 of the present invention.

[0037] Figure 4 This is a physical image of the powder conveying device obtained in Embodiment 1 of the present invention.

[0038] Wherein: 001-Top layer second mix; 002-Bottom layer second mix; 003-Laying base material; 004-Front material distributor; 005-Rear material distributor; 006-Exhaust direction. Figure 1 The straight arrow indicates the direction of movement of the sintering machine trolley; 101-Fabric roller; 102-Powder; 103-Dust collector powder discharge port; 104-Conveyor roller. Detailed Implementation

[0039] To better illustrate the objectives, technical solutions, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. The specific implementation methods, structures, features, and effects of the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art should understand that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0040] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0041] Unless otherwise specified, all raw materials used in this invention are commercially available.

[0042] The technical solution of the present invention will be further explained below with reference to specific embodiments.

[0043] This embodiment is used to illustrate the use of, for example Figure 1 A method for enriching valuable metals based on the sintering of multi-source metallurgical solid waste, as shown in the diagram, includes the following steps: I. Bottom layer mixture: Add 38 parts by weight of copper slag powder, 1.5 parts by weight of calcium chloride, 0.10 parts by weight of magnesium chloride, 0.05 parts by weight of ferric chloride, 0.10 parts by weight of calcium oxide, 3 parts by weight of copper tailings, 20 parts by weight of gold tailings, 1.2 parts by weight of coal powder and 0.6 parts by weight of quicklime into the mixer. Add 2.5 parts by weight of water during the mixing process and continue mixing for 1 minute to obtain the bottom layer mixture.

[0044] II. Second Mixing of the Bottom Layer: The first bottom layer mixture is fed into a granulator, and 3 parts by weight of water are continuously added and mixed for 2 minutes to obtain a second bottom layer mixture with uniform particle size and good air permeability. Because calcium chloride absorbs water, it is more likely to become the core material during the first mixing, and during the second mixing, it can grow into relatively larger granules. In this embodiment, the main body of the granules in this part is approximately 5-8 mm in size.

[0045] III. Top layer material mixing: Add 12 parts by weight of zinc-containing tailings, 5 parts by weight of zinc-containing ash, 5 parts by weight of gas ash, 0.6 parts by weight of carbon fuel and 0.3 parts by weight of lime into the mixer. Add 1.2 parts by weight of water during the mixing process and continue mixing for 1 minute to obtain the top layer material mixing.

[0046] IV. Second Mixing of Top Layer Material: The first layer mixture is fed into a granulator, and 1.5 parts by weight of water are continuously added and mixed for 1 minute to obtain a second layer mixture with uniform particle size. This part forms relatively smaller spheres compared to the bottom layer material. In this embodiment, the main body of the spheres in this part is approximately 3-5 mm in size.

[0047] V. Batch Material Distribution: A 50mm thick base material 003 (using the 10-20mm sintered material obtained from the previous sintering) is laid on the sintering machine trolley. Two material distributors (both existing circular roller distributors and reflector plate distributors) are installed in the forward direction of the sintering machine trolley. Figure 1 As shown, the rear feeder 005 lays the bottom layer of mixed material 002, and the front feeder 004 lays the top layer of mixed material 001. The trolley moves forward at a speed of 1.2 m / min (as shown). Figure 1 (As shown in the diagram, moving from left to right), the final total material layer thickness after distribution is 500mm, with the bottom layer of mixed material being 350mm thick and the top layer being 100mm thick. A physical image of the material distributor is shown below. Figure 3 As shown, Figure 3 In the middle, the bottom layer of mixed material or the top layer of mixed material (mixed material) is conveyed from the top and then distributed onto the sintering machine trolley by the material distribution roller according to the particle size.

[0048] Based on the composition of each raw material, the material composition on the sintering machine trolley is calculated as follows: TFe: 50wt.%, CaO: 6.58wt.%, MgO: 3.42wt.%, SiO2: 7.05wt.%, Al2O3: 2.59wt.%, MnO: 0.6wt.%, TiO: 0.65wt.%, Zn: 2.5wt.%, K2O: 0.55wt.%, Na2O: 0.52wt.%, Pb: 0.25wt.%, S: 0.6wt.%, P: 0.025wt.%, Au: 0.03ppm and Ag: 3.2ppm.

[0049] VI. Sintering Enrichment: Start the ignition device of the sintering machine, control the ignition temperature at 1100℃, and simultaneously start the top-down exhaust system (e.g., Figure 1 As shown, the exhaust direction (006) is from top to bottom, the exhaust velocity is 1.5 m / s, and the continuous sintering time is 30 minutes (the total sintering time for the same part of the material). During the high-temperature sintering process, calcium chloride, magnesium chloride, and ferric chloride in the bottom material react fully with valuable metals such as gold, silver, and titanium in the solid waste to generate easily vaporized metal chlorides, which enter the exhaust system with the flue gas. After the remaining material is cooled and solidified, a material with a total iron content of 50.98 wt.% is obtained, which can be directly used as blast furnace feed. The sintered ore (0.98 tons of sintered ore are produced per ton of raw material); the flue gas containing metal chlorides generated during the sintering process is discharged into the main flue through the exhaust system, where it naturally cools to below 150°C. The gaseous metal chlorides condense and combine with flue gas dust to form ash. The cooled flue gas is then sent to a bag filter to collect the dust, yielding high-value enriched powder mainly composed of valuable metals such as gold, silver, and titanium (0.02 tons of valuable metal-enriched powder are produced per ton of raw material). The powder collection process is as follows: Figure 4 As shown, powder 102 is discharged through the dust collector's powder discharge outlet 103 and then conveyed by a conveyor roller. Figure 4 The powder can also be seen to be fine and uniform.

[0050] Chemical analysis of the obtained powder revealed the following composition: TFe: 2.21 wt.%; Zn: 5.35 wt.%; K2O: 20.05 wt.%; Na2O: 16.85 wt.%; Au: 1.2 ppm; Ag: 158 ppm; Pb: 7.55 wt.%; Ti: 18.5 wt.%.

[0051] Thus, the recoveries of Fe, Zn, K2O, Na2O, Au, Ag, Pb, and Ti were T, respectively. Fe Recovery rates: 0.09%; Zn recovery rate: 4.28%; K2O recovery rate: 72.91%; Na2O recovery rate: 64.81%; Au recovery rate: 80.00%; Ag recovery rate: 98.75%; Pb recovery rate: 60.40%; Ti recovery rate: 94.98%.

[0052] It can be seen that the powder does not contain much Fe, but it can effectively enrich Zn, K, Na, Au, Ag, Pb and Ti. The enrichment effect of valuable metals is significant, and the product has high added value. This type of powder can be used to extract each precious metal separately through a wet process.

[0053] like Figure 2 The image shown is a physical picture of the sinter obtained in Example 1. Figure 2It can be seen that the obtained sinter particles are uniform, with no powder on the surface, and a yellowish-brown color, indicating that the main metallic element in the sinter is iron, and it appears to contain little other valuable metals. Furthermore, since chemical analysis of the powder shows that the valuable metals are basically concentrated in the powder, the obtained sinter contains virtually no of these metals. Therefore, it will not introduce relatively harmful elements from the blast furnace operation into the ironmaking process. Testing of the sinter obtained in this embodiment showed a drum strength of 71%, a drop strength of 86%, and a yield of 80%, fully meeting the requirements for blast furnace sinter and can be used directly as sinter.

[0054] In other words, all products generated in this embodiment are valuable products, and no solid waste is generated (traditional sintering processes generate a large amount of ash).

[0055] Example 2 This embodiment illustrates a method for enriching valuable metals based on the sintering of multi-source metallurgical solid waste with different parameters, including the following steps: I. Bottom layer mixture: 42 parts by weight of copper slag powder, 1.7 parts by weight of calcium chloride, 0.13 parts by weight of magnesium chloride, 0.08 parts by weight of ferric chloride, 0.15 parts by weight of calcium oxide, 6 parts by weight of copper tailings, 26 parts by weight of gold tailings, 2.9 parts by weight of coal powder and 1.6 parts by weight of quicklime are added to the mixer. During the mixing process, 3.5 parts by weight of water are added and the mixture is continuously mixed for 1.5 minutes to obtain the bottom layer mixture.

[0056] II. Second mixing of bottom layer material: The first mixing of bottom layer material is fed into the granulator, and 4.5 parts by weight of water are continuously added and mixed for 3 minutes to obtain the second mixing of bottom layer material.

[0057] III. Top layer material mixing: Add 16 parts by weight of zinc-containing tailings, 8 parts by weight of zinc-containing ash, 7 parts by weight of gas ash, 1.1 parts by weight of coal powder and 0.8 parts by weight of quicklime into the mixer. Add 1.6 parts by weight of water during the mixing process and continue mixing for 1.5 minutes to obtain the top layer material mixing.

[0058] IV. Second mixing of top layer material: The first top layer material is fed into the granulator, and 2.2 parts by weight of water are continuously added and mixed for 1.5 minutes to obtain the second top layer material.

[0059] V. Batch material distribution: A 60mm thick base material is laid on the sintering machine trolley. Two material distributors are set in the forward direction of the sintering machine trolley. The rear material distributor distributes the bottom layer of mixed material, and the front material distributor distributes the top layer of mixed material. The trolley moves forward at a speed of 1.5m / min. The total thickness of the material layer after distribution is 650mm, of which the bottom layer of mixed material is 450mm thick and the top layer of mixed material is 140mm thick.

[0060] Based on the composition of each raw material, the material composition on the sintering machine trolley is calculated as follows: TFe: 49 wt.%, CaO: 6.88 wt.%, MgO: 3.45 wt.%, SiO2: 6.95 wt.%, Al2O3: 2.60 wt.%, MnO: 0.8 wt.%, TiO: 0.65 wt.%, Zn: 2.5 wt.%, K2O: 0.65 wt.%, Na2O: 0.52 wt.%, Pb: 0.26 wt.%, S: 0.5 wt.%, P: 0.05 wt.%, Au: 0.03 ppm and Ag: 3.3 ppm.

[0061] VI. Sintering Enrichment: Start the ignition device of the sintering machine, control the ignition temperature at 1150℃, and simultaneously start the exhaust system with an exhaust velocity of 1.8m / s for continuous sintering for 25 minutes. Under high temperature conditions, the chloride additives in the bottom material react efficiently with valuable metals such as gold, silver, and titanium in the solid waste to generate easily gasifiable metal chlorides, which are discharged with the flue gas. After the remaining material is cooled and solidified, sinter with a total iron content of 52.76wt.% is obtained, which can be directly used as blast furnace feed (0.975 tons of sinter are produced per ton of raw material). The sintering flue gas is cooled to below 150℃ through the main flue, and the gaseous metal chlorides cool and condense to form ash, which is sent to the bag filter for collection to obtain valuable metal enriched powder (0.025 tons of valuable metal enriched powder are produced per ton of raw material).

[0062] Tests showed that the powder contained T Fe : 2.31wt.%; Zn: 5.51wt.%; K2O: 20.25wt.%; Na2O: 17.12wt.%; Au: 1.32ppm; Ag: 151ppm; Pb: 7.66wt.%; Ti: 15.8wt.%.

[0063] Thus, the recoveries of Fe, Zn, K2O, Na2O, Au, Ag, Pb, and Ti were T, respectively. Fe Recovery rates: 0.11%; Zn recovery rate: 5.96%; K2O recovery rate: 64.90%; Na2O recovery rate: 69.03%; Pb recovery rate: 63.83%; Ti recovery rate: 96.92%; Au recovery rate: 94.29%; Ag recovery rate: 96.79%.

[0064] Compared to Example 1, this embodiment increases the amount of fuel in the bottom mixture and increases the exhaust velocity. It was found that the amount of powder increased slightly, and the recovery of valuable metals in the ash increased, with a significant improvement in recovery rate. This is because the increased fuel amount raises the temperature of the bottom material compared to Example 1. Combined with the increased exhaust velocity, this makes it easier and more complete to strip the ash from the bottom material (enhancing the chloride reaction), thus more fully forming flue gas containing valuable metals. However, this setup also increases the amount of Fe entering the ash. Therefore, a trade-off is necessary. Overall, within the scope of this invention, valuable metal enrichment and high product added value can be achieved.

[0065] Example 3 This embodiment illustrates a method for enriching valuable metals based on the sintering of multi-source metallurgical solid waste with different parameters, including the following steps: I. Bottom Material Mixing: 46 parts by weight of copper slag powder, 1.9 parts by weight of calcium chloride, 0.15 parts by weight of magnesium chloride, 0.12 parts by weight of ferric chloride, 0.20 parts by weight of calcium oxide, 9 parts by weight of copper tailings, 33 parts by weight of gold tailings, 2.2 parts by weight of coal powder, and 2.6 parts by weight of quicklime are added to a mixer. During mixing, 4.5 parts by weight of water are added, and mixing continues for 2 minutes to obtain the bottom material mixture. A drum mixer (cylindrical mixer) is used.

[0066] II. Second Mixing of Bottom Layer Material: The first bottom layer material is fed into a granulator, and 6 parts by weight of water are continuously added and mixed for 4 minutes to obtain the second bottom layer material. The second mixing is performed in the second stage of a cylindrical mixer.

[0067] III. Top Layer Mixing: Add 21 parts by weight of zinc-containing tailings, 12 parts by weight of zinc-containing ash, 10 parts by weight of gas ash, 1.6 parts by weight of pulverized coal, and 1.3 parts by weight of quicklime to the mixer. Add 2.1 parts by weight of water during the mixing process and continue mixing for 2 minutes to obtain the top layer mixture. A drum mixer (cylindrical mixer) is used.

[0068] IV. Second Mixing of Top Layer Material: The first layer material is fed into the granulator, and 3 parts by weight of water are continuously added and mixed for 2 minutes to obtain the second layer material. The second mixing is performed in the second stage of a cylindrical mixer.

[0069] V. Batch material distribution: A 70mm thick base material is laid on the sintering machine trolley. Two material distributors are set in the forward direction of the sintering machine trolley. The rear material distributor distributes the bottom layer of mixed material, and the front material distributor distributes the top layer of mixed material. The trolley moves forward at a speed of 1.8m / min. The total thickness of the material layer after distribution is 800mm, of which the bottom layer of mixed material is 550mm thick and the top layer of mixed material is 180mm thick.

[0070] Based on the composition of each raw material, the material composition on the sintering machine trolley is calculated as follows: T Fe : 51.5wt.%, CaO: 6.98wt.%, MgO: 3.55wt.%, SiO2: 6.92wt.%, Al2O3: 2.26wt.%, MnO: 0.25wt.%, TiO: 0.68wt.%, Z n: 2.31wt.%, K2O: 0.78wt.%, Na2O: 0.62wt.%, Pb: 0.30wt.%, S: 0.6wt.%, P: 0.32wt.%, Au: 0.035ppm and Ag: 3.9ppm.

[0071] VI. Sintering Enrichment: Start the ignition device of the sintering machine, control the ignition temperature at 1200℃, and simultaneously start the exhaust system at a wind speed of 2.0 m / s for continuous sintering for 20 minutes. Under high temperature conditions, the chloride additives in the bottom material react fully with valuable metals such as gold, silver, and titanium in the solid waste to generate metal chlorides with low melting points and easy gasification, which are completely introduced into the flue gas with the exhaust airflow. After the remaining material is cooled and solidified, a high-quality sintered ore with an iron content of 50.02% is obtained, which can be directly used as blast furnace feed. The sintering flue gas is cooled to below 150℃ through the main flue, and the gaseous metal chlorides are completely cooled and condensed, combining with the flue gas dust to form high-value ash, which is sent to the bag filter to collect valuable metal enriched powder (0.019 tons of valuable metal enriched powder are generated per ton of raw material).

[0072] The powder was tested and found to contain: TFe: 2.31 wt.%; Zn: 5.51 wt.%; K2O: 20.25 wt.%; Na2O: 17.12 wt.%; Au: 1.32 ppm; Ag: 168 ppm; Pb: 7.66 wt.%; Ti: 18.9 wt.%.

[0073] Thus, the recoveries of Fe, Zn, K2O, Na2O, Au, Ag, Pb, and Ti were T, respectively. Fe Recovery rates: 0.09%; Zn recovery rate: 4.77%; K₂O recovery rate: 51.92%; Na₂O recovery rate: 55.23%; Pb recovery rate: 51.07%; Ti recovery rate: 92.75%; Au recovery rate: 75.43%; Ag recovery rate: 86.15%. The enrichment effect on valuable metals is significant, and the product has high added value.

[0074] Comparative Example 1 This comparative example is used to illustrate a comparative test (compared to Example 1) without using a distribution mixture, and includes the following steps: I. First Mixture: 38 parts by weight of copper slag powder, 1.5 parts by weight of calcium chloride, 0.10 parts by weight of magnesium chloride, 0.05 parts by weight of ferric chloride, 0.10 parts by weight of calcium oxide, 3 parts by weight of copper tailings, 20 parts by weight of gold tailings, 1.8 parts by weight of coal powder, 0.9 parts by weight of quicklime, 12 parts by weight of zinc-containing tailings, 5 parts by weight of zinc-containing ash, and 5 parts by weight of gas ash were added to a mixer. During the mixing process, 3.7 parts by weight of water were added, and mixing continued for 1 minute to obtain the first mixture. The calculated binary basicity of this mixture was 1.21, indicating a relatively low basicity.

[0075] II. Second Mixing: The first mixture is fed into the granulator, and 4 parts by weight of water are continuously added. The mixture is continuously mixed for 2.5 minutes to obtain the second mixture, with a particle size distribution of 3~8 mm.

[0076] III. Material laying: A 50mm thick base material is laid on the sintering machine trolley. A nine-roller material feeder is set in the forward direction of the sintering machine trolley. The trolley moves forward at a speed of 1.2m / min. The total thickness of the material layer after laying is 500mm. The nine-roller material feeder can naturally arrange the lower layer of the main body with larger particle size and the upper layer with smaller particle size.

[0077] Based on the composition of each raw material, the material composition on the sintering machine trolley is calculated as follows: TFe: 50 wt.%, CaO: 6.58 wt.%, MgO: 3.42 wt.%, SiO2: 7.05 wt.%, Al2O3: 2.59 wt.%, MnO: 0.6 wt.%, TiO: 0.65 wt.%, Zn: 2.5 wt.%, K2O: 0.55 wt.%, Na2O: 0.52 wt.%, Pb: 0.25 wt.%, S: 0.6 wt.%, P: 0.025 wt.%, Au: 0.03 ppm, and Ag: 3.2 ppm (since the overall amount of material added is the same as in Example 1, the material composition is also the same as in Example 1).

[0078] VI. Sintering enrichment: Start the ignition device of the sintering machine, control the ignition temperature at 1100℃, and simultaneously start the top-down exhaust system with an exhaust speed of 1.5m / s. Continuously sinter for 30 minutes (the total time for the same part of the material to be placed in the sintering process). During the high-temperature sintering process, calcium chloride, magnesium chloride, and ferric chloride in the sintering material react fully with valuable metals such as gold, silver, and titanium in the solid waste to generate easily gasifiable metal chlorides, which enter the exhaust system with the flue gas. After the remaining material is cooled and solidified, sinter with a total iron content of 50.88 wt.% is obtained, which can be directly used as blast furnace feed (0.982 tons of sinter are produced per ton of raw material). The flue gas containing metal chlorides generated during the sintering process is discharged into the main flue through the exhaust system. In the main flue, it is naturally cooled to below 150°C. The gaseous metal chlorides cool and condense and combine with the flue gas dust to form ash. Then, the cooled flue gas is sent to a bag filter to collect the dust collected in the filter, resulting in high-value enriched powder with valuable metals such as gold, silver, and titanium as the main components (0.018 tons of valuable metal enriched powder are produced per ton of raw material).

[0079] The powder was tested and found to contain: TFe: 2.21 wt.%; Zn: 4.35 wt.%; K2O: 18.02 wt.%; Na2O: 16.31 wt.%; Au: 0.6 ppm; Ag: 121 ppm; Pb: 6.05 wt.%; Ti: 10.2 wt.%.

[0080] Thus, the recoveries of Fe, Zn, K2O, Na2O, Au, Ag, Pb, and Ti were T, respectively. Fe Recovery rates: 0.08%, Zn recovery rate: 3.13%, K2O recovery rate: 58.97%, Na2O recovery rate: 56.46%, Pb recovery rate: 43.56%, Ti recovery rate: 47.13%, Au recovery rate: 36.00%, Ag recovery rate: 68.06%.

[0081] Since the raw materials are basically the same as in Example 1, except that the two separate mixing and step-by-step distribution were not performed, it can be seen that, compared to Example 1, under the same conditions, the ash content in this comparative example is relatively reduced, and the recovery rates of various valuable metals are relatively significantly lower. This is because step-by-step mixing and granulation were not implemented (and mixing was carried out without a reasonable limit on alkalinity; if a higher alkalinity of 1.8 or above were reasonably set, the reaction between chlorides and valuable metals would be enhanced. If a step-by-step mixing and distribution method were used, the alkalinity requirement would not be so strict), resulting in a higher content of valuable metals. Copper slag powder, copper tailings, and gold tailings are mixed with other solid wastes as a whole. During the sintering process, chlorides do not react effectively and specifically with these solid wastes rich in valuable metals. This results in excessive chloride accumulation in some areas and insufficient chloride in areas rich in valuable metals, leading to incomplete reaction with the valuable metals and a decrease in the recovery rate of each valuable metal. This demonstrates that the stepwise mixing and stepwise distribution method set in this invention can effectively enrich the solid waste rich in valuable metals, thereby enabling the effective enrichment and recovery of valuable metals from multi-source metallurgical solid wastes.

[0082] The core of this invention lies in the rational combination of multi-source metallurgical solid waste, a two-stage mixing process, a batch feeding method, and the high-temperature reaction characteristics of chloride additives with valuable metals, which promotes the formation of low-melting-point, easily gasifiable metal chlorides from valuable metals such as gold, silver, and titanium, thereby achieving the gasification separation of valuable metals from other materials. Ultimately, sintered ore that can be directly used as blast furnace feed and high-value valuable metal enrichment powder with gold, silver, and titanium as the main components are obtained simultaneously, achieving the dual goals of co-processing solid waste and recovering high-value resources.

[0083] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for enriching valuable metals based on sintering of multi-source metallurgical solid waste, characterized in that, Includes the following steps: I. Bottom Mixing: 38-46 parts by weight of copper slag powder, 1.5-1.9 parts by weight of calcium chloride, 0.10-0.15 parts by weight of magnesium chloride, 0.05-0.12 parts by weight of ferric chloride, 0.10-0.20 parts by weight of calcium oxide, 3-9 parts by weight of copper tailings, 20-33 parts by weight of gold tailings, 1.2-3.2 parts by weight of carbon fuel, and 0.6-2.6 parts by weight of lime are mixed in a mixer, and 2.5-4.5 parts by weight of water are added during the mixing process. The mixture is continued for 1-2 minutes to obtain the bottom mixing. II. Second mixing of bottom layer material: The obtained bottom layer first mixture is placed into a granulator and mixed for 2-4 minutes while continuously adding 3-6 parts by weight of water to obtain the second bottom layer mixture. III. Top layer material mixing: Mix 12-21 parts by weight of zinc-containing tailings, 5-12 parts by weight of zinc-containing ash, 5-10 parts by weight of gas ash, 0.6-1.6 parts by weight of carbon fuel and 0.3-1.3 parts by weight of lime in a mixer, and add 1.2-2.1 parts by weight of water during the mixing process, and continue mixing for 1-2 minutes to obtain the top layer material mixing. IV. Second mixing of top layer material: The obtained top layer first mixture is placed into a granulator and mixed for 1 to 2 minutes while continuously adding 1.5 to 3 parts by weight of water to obtain the bottom layer second mixture. V. Batch material distribution: A base material is laid on the sintering machine trolley. Two material distributors are set up in the direction of the sintering machine trolley's forward movement. The bottom layer of mixed material is distributed through the rear material distributor, and the top layer of mixed material is distributed through the front material distributor. As the sintering machine trolley moves forward, the bottom layer of mixed material is distributed on the base material, and the top layer of mixed material is distributed on the bottom layer of mixed material. The total thickness of the material layer is 500~800mm. VI. Sintering enrichment The sintering machine for the fabric in step V is ignited and sintered, and the exhaust fan is started from top to bottom. After continuous sintering, iron-containing sintered ore is obtained. At the same time, the flue gas generated during the sintering process is continuously discharged into the large flue to cool down through the exhaust fan. Then, the cooled flue gas is discharged to the dust collector, where the cooled dust is collected to obtain powder enriched with valuable metals.

2. The method for enriching valuable metals based on sintering of multi-source metallurgical solid waste according to claim 1, characterized in that, The carbon fuel is coke powder or anthracite powder; the lime material is one or more of quicklime, limestone, hydrated lime or dolomite.

3. The method for enriching valuable metals based on sintering of multi-source metallurgical solid waste according to claim 1, characterized in that, In step (1), the lime, copper tailings and gold tailings are all crushed before mixing, so that the particle size of the copper slag powder, calcium chloride, magnesium chloride, ferric chloride, calcium oxide, copper tailings, gold tailings, carbon fuel and lime are all below 5 mm. In step (3), the lime and zinc-containing tailings are crushed before mixing so that the particle size of the zinc-containing tailings, zinc-containing ash, gas ash, carbon fuel and lime are all below 4 mm.

4. The method for enriching valuable metals based on sintering of multi-source metallurgical solid waste according to claim 1 or 2, characterized in that, In step V, the thickness of the bottom layer of the second mixture is 1.5 to 3.5 times that of the top layer of the second mixture.

5. The method for enriching valuable metals based on sintering of multi-source metallurgical solid waste according to claim 1 or 2, characterized in that, In step V, the sintering machine is a negative pressure belt-type exhaust sintering machine.

6. The method for enriching valuable metals based on sintering of multi-source metallurgical solid waste according to claim 1 or 2, characterized in that, In step VI, the ignition temperature for ignition sintering is 1050~1200℃, the exhaust velocity is 1.5~2.6m / s, the exhaust pressure in the main flue is 8~13kPa, and the temperature of the high-temperature combustion zone is 1360~1480℃.

7. The method for enriching valuable metals based on sintering of multi-source metallurgical solid waste according to claim 1 or 2, characterized in that, The moving speed of the sintering machine trolley is 1.2~2.0m / min.

8. The method for enriching valuable metals based on sintering of multi-source metallurgical solid waste according to claim 1 or 2, characterized in that, The sinter obtained in step VI has a drum strength of 70-78%, a drop strength of 85-90%, and a yield of 78-88%.

9. The method for enriching valuable metals based on sintering of multi-source metallurgical solid waste according to claim 1 or 2, characterized in that, The chemical composition of the valuable metal-enriched powder contains: TFe: 1.02~3.32 wt.%; Zn: 3.89~7.05 wt.%; K2O: 16.25~29.85 wt.%; Na2O: 11.06~18.21 wt.%. Au: 0.9~1.3ppm; Ag: 150~180ppm; Pb: 7.0~8.5 wt.%; Ti: 15.8~19.5 wt.%.

10. The method for enriching valuable metals based on sintering of multi-source metallurgical solid waste according to claim 1 or 2, characterized in that, In step VI, the mass of sinter obtained from each ton of raw material is 0.9 to 0.99 tons, and the mass of valuable metal-enriched powder obtained from each ton of raw material is 0.01 to 0.1 tons.

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