A kind of pyrometallurgical smelting volatile enrichment low-grade germanium-containing material germanium burden ore method

Abstract

The application discloses a kind of pyrometallurgical smelting volatile enrichment germanium in low-grade germanium-containing material burdened ore method, belongs to rare metal germanium metallurgy technical field, specifically relates to a kind of pyrometallurgical enrichment pretreatment technology of low-grade germanium-containing material.The method of the application includes raw material pretreatment, raw material mixing, briquetting, briquetting drying and the like.The method of the application solves the problems of low recovery efficiency, high energy consumption, great environmental impact, substandard briquetting performance and high production cost when processing low-grade, high-silicon germanium-containing material in the prior art, provides "high strength, low powder rate and easy volatilization" high-quality germanium raw material for subsequent pyrometallurgical smelting, greatly improves germanium recovery rate and enrichment ratio, reduces industrial production cost, and improves germanium resource utilization rate.

Description

Technical Field

[0001] This invention belongs to the field of rare metal germanium metallurgy technology, specifically relating to a pyrometallurgical enrichment pretreatment technology for low-grade germanium-containing materials. Background Technology

[0002] Although my country possesses abundant recycled germanium resources, a large portion of these resources exhibit complex compositions, predominantly existing as low-grade germanium materials that are difficult to beneficiate, such as low-germanium-content waste (0.1-1.5% germanium) and high-silicon, low-germanium waste slag (0.005-0.1% germanium, SiO2>50%). Furthermore, the recycling of germanium-containing waste faces challenges due to traditional processes, including long processing times, high energy consumption, significant pollution, low recovery rates, and high costs, resulting in a recycling rate of less than 60%. Long-term stockpiling of these materials poses serious environmental and ecological risks. Therefore, developing efficient pyrometallurgical enrichment technologies for low-grade germanium-containing materials is of significant practical importance for improving germanium resource utilization, reducing production costs and environmental impact, and ensuring the security of the germanium strategic metal supply chain.

[0003] Currently, germanium-containing material recovery technologies mainly focus on three areas: hydrometallurgy, pyrometallurgy, and adsorption separation. Hydrometallurgy, represented by sulfuric acid leaching-solvent extraction and sulfuric acid leaching-tannin precipitation processes, has been applied to zinc smelting for germanium extraction. However, this process has poor adaptability to high-silica, low-germanium materials, with germanium leaching rates generally below 50%. Furthermore, it generates large amounts of wastewater, suffers from significant silica gel clogging issues, and presents difficulties in subsequent treatment. Pyrometallurgy typically uses fuming furnaces to volatilize and enrich germanium at high temperatures. While capable of handling complex matrices, it suffers from low recovery efficiency for silica content exceeding 50%, with germanium recovery rates below 60%. The high energy consumption for treating slag from high-silica matrices hinders industrialization. In terms of wet (acid or alkali) leaching-adsorption separation technology, leaching rates are below 70%, reagent consumption and wastewater volume are excessive and difficult to treat. Existing adsorbents also exhibit drawbacks such as high co-adsorption rates for silicon and low separation efficiency. In some technologies reported abroad, the microbial leaching method takes as long as 30-60 days and is not suitable for these types of materials.

[0004] Chinese patent CN202010123456.7 discloses a method for acid leaching desiliconization in high-silicon germanium slag, but it only improves the desiliconization step in the wet process and does not solve the problem of raw material compatibility in pyrometallurgical treatment. The method for preparing germanium ion polymers proposed in Chinese patent CN201910567890.1 still falls under the category of adsorption materials, with core ligand design relying on imports, and its enrichment effect on low-grade germanium-containing materials is limited. US20180002215A1 from UOP in the United States developed a highly selective germanium chelating resin with a silicon selectivity coefficient of 500, but it does not address the synergistic compatibility between ore pretreatment and pyrometallurgical enrichment. While the microwave-assisted leaching technology disclosed in Korean patent KR1020200001234B1 can increase the germanium leaching rate to 75%, the equipment investment is high, and it still belongs to the wet system, failing to solve the problem of efficient germanium enrichment from high-silicon, low-grade germanium-containing materials. None of these patents involve systematic research on batching and pelletizing technology for the physicochemical properties of pyrometallurgical smelting of low-grade germanium-containing materials.

[0005] Existing enrichment technologies for low-grade germanium-containing materials have the following shortcomings:

[0006] 1. Traditional wet and pyrometallurgical processes are difficult to efficiently process low-grade, high-silicon, germanium-containing materials, resulting in either poor adaptability or high energy consumption and heavy pollution.

[0007] 2. Existing technologies focus on optimizing a single step and lack pretreatment technologies for pyrometallurgical enrichment. When low-grade germanium-containing materials are directly smelted, problems such as dust flying, low volatile enrichment, and incomplete reaction are likely to occur.

[0008] 3. The compatibility between the pellet ore formulation and the process is insufficient. The selection and proportion of existing binders, reducing agents and fluxes lack systematic optimization, making it difficult to meet the industrial requirements of "compressive strength ≥500N / ball and pulverization rate <5%", resulting in low germanium enrichment ratio and unstable recovery rate during subsequent smelting.

[0009] 4. There is a lack of targeted pretreatment solutions for the problems faced by downstream wet processes, such as "large material processing volume, high acid and alkali consumption, and difficult wastewater treatment". Summary of the Invention

[0010] This invention aims to provide a method for batching and agglomerating low-grade germanium-containing materials for pyrometallurgical volatilization and enrichment. It solves the problems of low recovery efficiency, high energy consumption, significant environmental impact, substandard agglomerate performance, and high production costs in the processing of low-grade, high-silicon germanium-containing materials by existing technologies. It provides high-strength, low-powder, and easily volatile high-quality germanium raw materials for subsequent pyrometallurgical smelting, thereby significantly improving germanium recovery rate and enrichment ratio, reducing industrial production costs, and increasing germanium resource utilization.

[0011] A method for enriching germanium in low-grade germanium-containing materials through pyrometallurgical volatilization in batching pellets, characterized by the following steps:

[0012] Step S1, Raw material pretreatment:

[0013] A mixture of high-silicon, low-germanium waste residue containing 0.005-1.5% germanium and low-grade germanium ore is crushed, wherein the mass fraction of the high-silicon, low-germanium waste residue is 50%-75%, and the moisture content of the raw materials is tested.

[0014] Step S2, Raw material mixing:

[0015] The low germanium content raw material is initially mixed with reducing agent and flux in a closed mixer for 2-3 minutes; then the pre-mixed composite binder is added and dry-mixed for 1-2 minutes; finally, the metered water is evenly sprayed through an atomizing nozzle while stirring until the material forms a suitable viscosity and there is no local water accumulation or clumping.

[0016] The raw materials, by weight, include 75-85 parts of low-germanium raw material, 2.5-7.5 parts of reducing agent, 2-7 parts of flux, and 2-4 parts of binder; the amount of water added is 10-20% of the total weight of the raw materials.

[0017] Step S3, pressing and shaping:

[0018] The uniformly mixed raw materials are fed into a briquetting machine to form briquettes, with a briquetting particle size of 30-50mm.

[0019] Step S4, Drying the ore pellets:

[0020] After the shaped ore is dried, it is discharged after the moisture content is tested to be ≤1%.

[0021] The dried ore pellets are screened through a screen. Qualified pellets are sent to the storage bin, while unqualified pellets and powders are returned to the mixer and pressed into pellets again with other materials.

[0022] The reducing agent is one of coke and sodium sulfite, or a mixture thereof in a 1:1 weight ratio;

[0023] The flux is one or a mixture of several of calcium fluoride, sodium carbonate, borax, and trisodium phosphate in the same mass ratio;

[0024] The composite binder is a mixture of carboxymethyl cellulose and pregelatinized starch in a weight ratio of 1:1.

[0025] The material develops a suitable viscosity, specifically, so that the material can be formed into a "clump when squeezed in the hand and does not fall apart when released".

[0026] The method of the present invention has the following technical effects:

[0027] The efficiency of germanium enrichment through pyrometallurgical volatilization is significantly improved. After treatment using this method, high-valence germanium compounds are reduced to low-temperature, volatile GeO gas. The flux inhibits impurity volatilization and lowers the melting point of the slag. The germanium recovery rate increases from 76% (without pretreatment and direct smelting) to over 90%, and the enrichment factor increases from 8 times to over 15 times. This effectively solves the industry pain point of low recovery efficiency for low-grade germanium-containing materials.

[0028] The performance of the pellets meets industrial requirements. The composite binder achieves a room temperature compressive strength of ≥500N / ball and a powder rate of <5%. It has outstanding resistance to breakage and pulverization, can withstand mechanical impact during transportation and smelting, avoids germanium loss due to powder loss, ensures stable recovery rate, and maximizes the utilization rate of germanium resources.

[0029] Energy consumption and production costs are reduced. The calorific value balance design of low germanium raw materials reduces the input of external fuels, and precise moisture control reduces wastewater generation and energy consumption of water gasification in the smelting process, thus reducing wastewater generation and treatment costs.

[0030] It has strong industrial adaptability, simple and easy-to-control process flow, and can achieve continuous production through automation system. It can adapt to different production capacity requirements, and has a large and stable material handling capacity. The finished ore pellets have stable quality and strong traceability, which meets the requirements of raw materials for large-scale production.

[0031] It has a wide range of applications and can be used with a variety of materials such as low-grade ore containing 0.005-1.5% germanium and high-silicon waste. By appropriately adjusting the ratio of flux and reducing agent, it can cope with raw materials with different impurity compositions, solving the problem of poor adaptability of traditional processes to complex matrix materials. Attached Figure Description

[0032] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0033] Example 1: A method for batching and enriching germanium in low-grade germanium-containing materials by pyrometallurgical volatilization, the method involving the following specific steps and equipment.

[0034] The method includes the following steps:

[0035] Step S1, Raw material pretreatment:

[0036] A mixture of high-silicon, low-germanium waste residue containing 0.75% germanium and low-grade germanium ore was crushed. The high-silicon, low-germanium waste residue and low-grade germanium ore each contained 50% by weight. The moisture content of the crushed germanium-containing raw material was tested and found to be 8%.

[0037] Step S2, Raw material mixing:

[0038] Add the low germanium content raw material to the vertical shaft closed mixer as the base material and mix for 1 minute. Then, simultaneously add the reducing agent and flux and mix for 2-3 minutes in the closed mixer. Next, add the pre-mixed composite binder and continue dry mixing for 1-2 minutes. Finally, spray the metered water evenly through the atomizing nozzle while stirring, and wet mix for 5-10 minutes, preferably 7 minutes, with a water spraying speed of 5 kg / min. The final material reaches the target molding humidity of 15%, that is, the state of "forming a ball when squeezed and not falling apart when released", with no local water accumulation or dry material residue.

[0039] The total amount of mixed raw materials is 2000 kg, including 1720 kg of low germanium content raw materials, 100 kg of reducing agent, 120 kg of flux, and 60 kg of binder. The amount of water added is 284 kg.

[0040] Step S3, pressing and shaping:

[0041] S3-1, Feed control: After the mixing is completed, the material is fed into the feed inlet of the twin-shaft pellet mill at a uniform speed through a closed chute. The feed speed is controlled at 50kg / min to match the processing capacity of the twin shafts and increase the output. There is no need to worry about dust loss because the closed structure of the equipment can effectively lock the material.

[0042] S3-2, Rolling and Crushing: The front-end rolling and crushing twin-shaft rollers squeeze and crush the material, breaking up large agglomerates, increasing the material density, reducing waste generation from the source, and the rolled material directly enters the rear-end pelletizing unit without intermediate transfer.

[0043] S3-3, extrusion agglomeration: The agglomeration rollers at the rear end use extrusion to squeeze the material out of the die, forming round cake-shaped agglomerates with a diameter of 50 mm and uniform particle size. Because the die size is fixed, the agglomerate size is highly consistent and no manual preliminary screening is required.

[0044] Step S4, Drying the ore pellets:

[0045] The formed ore pellets are directly conveyed into a rotary oven via a conveyor belt at the discharge port and dried at 160℃ for at least 120 minutes. The rotating lifting plates ensure that the ore pellets are heated evenly. The moisture content is ≤1%, the compressive strength of the discharged material is ≥500N / ball, and the powder content is <5%.

[0046] Step S5, sieve and return material:

[0047] After drying, the briquettes are conveyed to a screening and return device. They are screened through a 10mm screen, resulting in uniform briquette size. The non-conforming particles are mainly small amounts of powder or broken briquettes. These non-conforming materials are recycled and returned to the mixer via a tipping bucket for further mixing or, after testing, are mixed with water and returned to the twin-shaft briquetting machine inlet for re-extrusion molding. The raw material utilization rate is ≥99%. Since the non-conforming material is dried, it cannot be directly briquetized and therefore cannot be directly returned to the twin-shaft briquetting machine.

[0048] Step S6, Weighing and Automatic Packaging:

[0049] After the qualified ore is naturally cooled to room temperature by the conveyor belt, it is cooled for about 15 minutes. Then, it is automatically metered and weighed according to the preset batch usage of 500 kg and stored in a separate silo for later use.

[0050] The method of this invention is implemented using a batching and pelletizing equipment system, which consists of an automatic batching unit, a precision weighing unit, a closed mixing unit, a biaxial pressing pelletizing unit, a rotary drying unit, a sieving and return unit, and a cooling and storage unit. The system achieves full-process automated control via PLC, allowing real-time adjustment of parameters for each unit, data traceability, and effective avoidance of human error. This ensures stable and efficient operation of the batching and pelletizing process, with a maximum batch capacity of 2000 kg, meeting the needs of large-scale production.

[0051] The automatic batching unit consists of four silos that store germanium-containing raw materials, reducing agents, fluxing agents, and binders respectively. The PLC controls the opening and closing of high-precision electronic valves to accurately feed materials according to a preset weight ratio. The inner wall anti-stick coating avoids wall adhesion errors.

[0052] The precise weighing unit is used to weigh and dispense each raw material. It uses a pressure sensor with an accuracy of ±0.1%. The weight data is calibrated in real time with the set proportion and serves as a signal for the PLC to control the opening and closing of the high-precision electronic valve of the automatic dispensing unit.

[0053] The enclosed mixing unit is used for mixing raw materials. It is a fully enclosed vertical shaft mixer that mixes materials in stages according to the principle of "dry first, then wet". The mixer first dry mixes the germanium-containing raw materials with reducing agent and flux, then adds binder and mixes again, and then sprays water for wet mixing. During wet mixing, the speed and atomized water volume are dynamically adjusted to ensure that the materials are evenly bonded.

[0054] The dual-axis pelletizing unit is used to press the mixed raw materials into pellets. The front rolling roller pre-presses and shapes the material, and the rear die roller extrudes it into spherical pellets with adjustable aperture, allowing for direct conveying and reducing spillage.

[0055] The rotary drying unit is used for drying ore pellets. It adopts a rotary oven drying method, in which the conveyor belt inside the oven turns the ore pellets over and over, ensuring uniform and controllable temperature, preventing cracking and loosening, and automatically discharging the material once the moisture content meets the standard.

[0056] The sieving and return unit is used for sieving and returning materials. The vibrating screen separates unqualified materials (scrap materials and powder materials) and automatically returns them to the briquetting machine for recycling.

[0057] The system uses enclosed chute conveying between its units to reduce dust and germanium loss.

[0058] The device needs to be debugged before use, specifically including:

[0059] 1. Equipment Inspection: Inspect the integrity of the closed structure of the twin-shaft briquetting machine (front-end rolling twin shafts + rear-end die forming roller) to ensure good sealing of the inlet and outlet; check the linkage of the four conical hoppers, weighing conical hopper, vertical shaft enclosed mixer, rotary oven, sieving and return device, weighing conveyor belt and automatic packaging device to ensure no leakage during material transfer.

[0060] 2. Equipment parameter preset: Input process parameters through the PLC control system to set the gap between the front rolling rollers of the twin-shaft pellet mill to 0.5cm, the rotation speed to 30r / min, and the diameter of the rear die to 20mm (to match the target pellet particle size); the parameters of the vertical shaft enclosed mixer are: dry mixing speed 100r / min, wet mixing speed 80r / min; the rotary oven drying temperature is 160℃, and the drying time is 120 minutes.

[0061] 3. Calibration and zeroing: Calibrate the moisture meter and weighing system (error ±0.2%), and zero the control system to ensure accurate parameter execution.

Claims

1. A method for batching and enriching germanium in low-grade germanium-containing materials by volatilization through pyrometallurgical smelting, characterized in that... The method includes the following steps: Step S1, Raw material pretreatment: A mixture of high-silicon, low-germanium waste residue containing 0.005-1.5% germanium and low-grade germanium ore is crushed, wherein the mass fraction of the high-silicon, low-germanium waste residue is 50%-75%, and the moisture content of the raw materials is tested. Step S2, Raw material mixing: The low germanium content raw material is initially mixed with reducing agent and flux in a closed mixer for 2-3 minutes; then the pre-mixed composite binder is added and dry-mixed for 1-2 minutes; finally, the metered water is evenly sprayed through an atomizing nozzle while stirring until the material forms a suitable viscosity and there is no local water accumulation or clumping. The raw materials, by weight, include 75-85 parts of low-germanium raw material, 2.5-7.5 parts of reducing agent, 2-7 parts of flux, and 2-4 parts of binder; the amount of water added is 10-20% of the total weight of the raw materials. Step S3, pressing and shaping: The uniformly mixed raw materials are fed into a briquetting machine to form briquettes, with a briquetting particle size of 30-50mm. Step S4, Drying the ore pellets: After the shaped ore is dried, it is discharged after the moisture content is tested to be ≤1%.

2. The method for batching and enriching germanium in low-grade germanium-containing materials by volatilization through pyrometallurgical smelting as described in claim 1, characterized in that... The dried ore pellets are screened through a screen. Qualified pellets are sent to the storage bin, while unqualified pellets and powders are returned to the mixer and pressed into pellets again with other materials.

3. The method for batching and enriching germanium in low-grade germanium-containing materials by volatilization through pyrometallurgical smelting as described in claim 1, characterized in that... The reducing agent is one of coke and sodium sulfite, or a mixture thereof in a 1:1 weight ratio; The flux is one or a mixture of several of calcium fluoride, sodium carbonate, borax, and trisodium phosphate in the same mass ratio; The composite binder is a mixture of carboxymethyl cellulose and pregelatinized starch in a weight ratio of 1:1.

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