Bottom mud heavy metal intelligent separation technology based on occurrence state regulation and control

Abstract

The invention relates to the technical field of environment detection and pollution treatment, in particular to an intelligent bottom mud heavy metal separation technology based on occurrence state regulation and control, which comprises the following steps: determining the binding state of heavy metal carbonate, the binding state of iron and manganese oxides and the total content through morphological analysis, and implementing particle size grading pretreatment; in the form transformation stage, the redox potential is accurately controlled to be-200 mV to-350 mV based on a dynamic agent adding algorithm, and heavy metal is promoted to be converted into sulfide and metal simple substances; the collaborative separation adopts a gradient separation process to separate sulfides and metal elementary substances; and in the product recycling stage, sulfide concentrate is subjected to metallurgical utilization, metal simple substances are directly recycled, purified bottom mud is used for soil improvement, and separated wastewater is subjected to adsorption-membrane treatment closed-loop recycling. Through a morphological diagnosis and gradient separation cooperation mechanism, the problems of low efficiency and high pollution of a traditional process are solved, the heavy metal recovery rate is remarkably increased, and zero discharge of wastewater is achieved.

Description

Technical Field

[0001] The present invention relates to the field of environmental monitoring and pollution control technology, specifically to an intelligent sorting technology for heavy metals in sediment based on occurrence state regulation, which is particularly suitable for the repair and resource recovery of heavy metal-contaminated sediment. Background Art

[0002] Current technologies for treating heavy metals in river sediments mainly include chemical stabilization, solidification landfill, and physical separation. Chemical stabilization forms stable complexes with heavy metals by adding passivating agents to inhibit their activity, but it cannot recycle resources and its long-term stability is easily affected by environmental conditions. Solidification landfill uses cement and other curing agents to wrap contaminated sediments and then bury them. Although it can block the migration of pollution, it permanently occupies land and has no resource benefits. Physical separation technologies, such as magnetic separation and flotation, can directly separate heavy metals, but are restricted by characteristics such as occurrence form, sediment particle size, and organic matter content, resulting in low separation efficiency.

[0003] In the existing technology for the remediation and resource recovery of heavy metal-contaminated sludge, the sorting process is not designed based on the differences in the occurrence forms of heavy metals, such as carbonate-bound states and iron-manganese oxide-bound states. This results in low sulfide conversion rate and low metal recovery rate. The addition of reagents relies on empirical estimation and cannot dynamically respond to the physical and chemical properties of the sludge. The cost of sorting wastewater treatment is high and the reuse rate is low, which easily causes secondary pollution.

[0004] Therefore, in order to improve the sulfide conversion rate, metal recovery rate and wastewater treatment, an intelligent sorting technology for heavy metals in sediments based on occurrence state regulation was proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide an intelligent sorting technology for heavy metals in sediments based on the regulation of occurrence state. By means of targeted regulation of occurrence morphology and coordinated optimization of gradient sorting process, the efficiency of heavy metal sulfide sorting can be improved, and the recovery rate of heavy metal resources and zero discharge of sorting wastewater can be achieved simultaneously, thus avoiding the problems of low efficiency, waste of resources and secondary pollution coexisting in traditional technologies.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an intelligent separation technology for heavy metals in sediment based on occurrence state regulation, comprising the following steps:

[0007] S1. Morphological Analysis and Sediment Classification: River sediment samples were prepared into analytical slurry. The carbonate-bound, iron-manganese oxide-bound, organic sulfide-bound, and residual heavy metal contents in the slurry were determined by a stepwise chemical extraction method. Particle size classification was also performed simultaneously, and the total heavy metal content was determined. Mud with an organic matter content exceeding 6% was labeled as high-organic matter sediment.

[0008] S2. Morphological transformation treatment: adding a sulfiding agent and a reducing agent combination to the slurry, controlling the redox potential to be between -200 mV and -350 mV, so as to transform carbonate-bound heavy metals into sulfides and iron-manganese oxide-bound heavy metals into elemental metals, thereby obtaining a morphologically transformed slurry;

[0009] S3, collaborative separation: the morphology-transformed mud is sequentially fed into a flotation unit to separate sulfides and a magnetic separation unit to separate metal elements. The remaining material after separation is purified mud, and separation wastewater is generated during the separation process.

[0010] S4. Product resource utilization: The sulfide concentrate separated by the flotation unit is used as metallurgical raw material, the metal element concentrate separated by the magnetic separation unit is directly recovered, the purified mud is used for soil improvement after meeting environmental protection standards, and the sorting wastewater is recycled after treatment.

[0011] Furthermore, the dosage of the vulcanizing agent and reducing agent combination in the morphological transformation treatment is determined by the following formula:

[0012]

[0013] in, is the dosage of vulcanizing agent, in moles per kilogram of dry mud; is the morphological transformation coefficient, ranging from 0.6 to 1.0; is the dosage of reducing agent, in moles per kilogram of dry mud; is the reduction efficiency coefficient, ranging from 0.4 to 0.8; is the carbonate-bound heavy metal content, in mg per kilogram; The content of heavy metals bound to iron and manganese oxides, in mg per kilogram; is the total content of heavy metals, in mg per kilogram; It is the amount of sediment treated, in kg.

[0014] Furthermore, the morphology conversion coefficient Adjust according to the following rules based on the characteristics of the sediment:

[0015] When the sediment pH is less than 6.0, The value is reduced by 0.1-0.2

[0016] When the organic matter content of sediment is greater than 5%, The value increases by 0.15-0.25.

[0017] Furthermore, the flotation unit operation includes a first stage and a second stage:

[0018] In the first stage, a dithiocarbamate collector is added to separate the main sulfide at a pH value of 4.5 to 5.5;

[0019] The second stage adjusts the pH value to 7.0 to 8.0 and supplements xanthate collector to deeply remove residual sulfide.

[0020] Furthermore, the operation of the magnetic separation unit includes a first gradient sorting and a second gradient sorting, wherein the first gradient sorting uses a magnetic field strength of 0.5 to 0.8 T to separate ferromagnetic metal elements, and the second gradient sorting uses a magnetic field strength of 1.2 to 1.5 T to separate paramagnetic metal elements.

[0021] Furthermore, a closed-loop control system is set up in the morphological transformation processing and coordinated sorting, and the closed-loop control system includes morphological transformation monitoring and magnetic separation efficiency regulation. The morphological transformation monitoring detects the amount of sulfide generated in real time through an X-ray diffractometer, and triggers the sulfiding agent addition program when the conversion rate is less than 75%; the magnetic separation efficiency regulation detects the metal element content through a magnetic susceptibility sensor, and optimizes the magnetic separation intensity when the recovery rate is less than 80%.

[0022] Furthermore, the morphological analysis and sediment classification particle size classification treatment is carried out, and the mud is separated into coarse particles > 150 μm, medium particles 38-150 μm and fine particles < 38 μm by a hydrocyclone. The coarse particles are ultrasonically cleaned with a citric acid solution with a mass concentration of 5%-8% to remove surface oxides. The medium particles are directly subjected to the morphological transformation treatment. The fine particles are added with a sodium hexametaphosphate dispersant with a mass concentration of 0.1%-0.3% to inhibit agglomeration.

[0023] Furthermore, the high-organic matter sludge is pretreated, and a composite oxidant consisting of potassium persulfate and ferric citrate is added at a molar ratio of 1:1-2. After the reaction is carried out at pH 3.0-3.5, humic acid colloid separation is achieved by centrifugation.

[0024] Furthermore, the sorting wastewater treatment includes heavy metal removal, salt removal and water recycling. The heavy metal removal uses chelating resin to adsorb and remove heavy metal ions. The salt removal removes soluble salts through membrane separation technology. The water recycling reuses the treated water in the mud preparation process to form a circulating water system.

[0025] Furthermore, the dynamic optimization strategy for the sorting sequence of the collaborative sorting collects metal market price data in real time and gives priority to sorting metal types with high unit economic benefits; the dynamic optimization strategy for the sorting sequence is updated every 24 hours and sent to the sorting equipment control terminal.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The distribution characteristics of carbonate-bound and iron-manganese oxide-bound heavy metals are accurately identified through a step-by-step chemical extraction method. Combined with the coarse particle pickling and fine particle dispersion treatment in the particle size classification pretreatment process, the uniformity and contact efficiency of the subsequent morphological transformation reaction are significantly improved, achieving the simultaneous optimization of the recovery purity of heavy metal components and the overall sorting efficiency.

[0028] 2. The dosage of sulfiding agent is dynamically calculated based on the ratio of carbonate-bound content to total heavy metal content. At the same time, a real-time compensation mechanism for pH value and organic matter content is introduced to achieve a precise match between the dosage of the agent and the physical and chemical properties of the sediment, ensuring the process stability of the sulfide conversion rate and the amount of metal element generated.

[0029] 3. The flotation unit adopts a pH segmentation control strategy, preferentially separating highly hydrophobic sulfides under weakly acidic conditions and deeply removing residual sulfides under near-neutral conditions; the magnetic separation unit is designed with a gradient magnetic field strength to specifically separate ferromagnetic and paramagnetic metal elements; this synergistic process significantly reduces cross-contamination of different metal components and improves the direct utilization of the sorting products.

[0030] 4. The online monitoring system provides real-time feedback on sulfide conversion rate and metal recovery efficiency, triggering a dynamic control program to avoid resource waste due to incomplete reaction or mismatch of sorting parameters; the sorted wastewater is subjected to heavy metal interception and desalination through chelating resin adsorption and membrane separation technology, and the treated water is reused in a closed loop, solving the problems of high wastewater treatment costs and low reuse rates.

[0031] 5. Based on the dynamic optimization of metal market prices, the sorting priority can be significantly improved to significantly increase the resource utilization benefits of each unit of sludge treatment; the purified sludge meets the agricultural soil improvement standards, and the sulfide concentrate and metal elements can be directly used in the metallurgical industry, realizing the deep integration of pollution control and resource regeneration. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the overall flow chart of the core process and product resource utilization of the present invention;

[0033] Figure 2 This is a diagram of the morphological analysis and preprocessing module of the present invention;

[0034] Figure 3 This is a diagram of the morphological transformation processing module of the present invention;

[0035] Figure 4 This is a diagram of the collaborative sorting module of the present invention. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] See also Figures 1 to 4 The present invention provides a technical solution: an intelligent separation technology for heavy metals in sediment based on the regulation of occurrence state, comprising the following steps:

[0038] S1. Morphological analysis and sediment classification: River sediment samples were prepared into analytical slurry. The carbonate-bound, iron-manganese oxide-bound, organic sulfide-bound, and residual heavy metal contents in the slurry were determined by a stepwise chemical extraction method. Particle size classification was also performed simultaneously, and the total heavy metal content was determined. Mud with an organic matter content exceeding 6% was labeled as high-organic matter sediment.

[0039] S2. Morphological transformation treatment: adding a sulfiding agent and a reducing agent combination to the mud, controlling the redox potential to be between -200 mV and -350 mV, so that the carbonate-bound heavy metals are transformed into sulfides and the iron-manganese oxide-bound heavy metals are transformed into elemental metals, thereby obtaining a morphologically transformed mud;

[0040] S3, Co-separation: The morphologically transformed mud is sequentially fed into the flotation unit to separate sulfides and the magnetic separation unit to separate metal elements. The remaining material after separation is the purified mud, and the separation process generates separation wastewater;

[0041] S4. Product resource utilization: The sulfide concentrate separated by the flotation unit is used as metallurgical raw material, the metal element concentrate separated by the magnetic separation unit is directly recovered, the purified mud is used for soil improvement after passing environmental protection testing, and the sorting wastewater is recycled after treatment;

[0042] Through the full process design of morphological analysis, transformation processing, coordinated sorting and resource utilization, targeted regulation of heavy metal occurrence forms can be achieved, significantly improving sorting efficiency and resource utilization rate, while reducing the risk of secondary pollution.

[0043] The dosage of the vulcanizing agent and reducing agent combination in the morphological transformation treatment is determined by the following formula:

[0044]

[0045] in, is the dosage of vulcanizing agent, in moles per kilogram of dry mud; is the morphological transformation coefficient, ranging from 0.6 to 1.0; is the dosage of reducing agent, in moles per kilogram of dry mud; is the reduction efficiency coefficient, ranging from 0.4 to 0.8; is the carbonate-bound heavy metal content, in mg per kilogram; The content of heavy metals bound to iron and manganese oxides, in mg per kilogram; is the total content of heavy metals, in mg per kilogram; is the amount of sediment treated, in kg;

[0046] The dosage of reagents is calculated based on the dynamic ratio of carbonate-bound state to total content, accurately matching different sediment characteristics, avoiding excessive or insufficient reagents, improving reaction efficiency and reducing raw material waste.

[0047] Morphological transformation coefficient Adjust according to the following rules based on the characteristics of the sediment:

[0048] When the sediment pH is less than 6.0, The value is reduced by 0.1-0.2

[0049] When the organic matter content of sediment is greater than 5%, The value increases by 0.15-0.25;

[0050] The conversion coefficient is adjusted through a real-time compensation mechanism of pH value and organic matter content, enhancing the process's adaptability to fluctuations in the sediment environment and ensuring that the sulfide conversion rate is stable and controllable.

[0051] The flotation unit operation consists of the first and second stages:

[0052] In the first stage, under the condition of pH 4.5 to 5.5, dithiocarbamate collector is added to separate the main sulfides;

[0053] In the second stage, the pH value is adjusted to 7.0 to 8.0, and xanthate collector is added to deeply remove residual sulfide;

[0054] The staged flotation strategy is combined with pH gradient control and collector optimization to achieve graded enrichment and deep removal of sulfides.

[0055] The operation of the magnetic separation unit includes a first gradient separation and a second gradient separation. The first gradient separation uses a magnetic field strength of 0.5 to 0.8 T to separate ferromagnetic metal elements, and the second gradient separation uses a magnetic field strength of 1.2 to 1.5 T to separate paramagnetic metal elements.

[0056] The gradient magnetic field strength is designed to target the magnetic differences between ferromagnetic and paramagnetic metals, effectively separating different metal elements, improving product purity and reducing cross contamination.

[0057] A closed-loop control system is set up for morphological transformation processing and coordinated sorting. The closed-loop control system includes morphological transformation monitoring and magnetic separation efficiency control. The morphological transformation monitoring uses an X-ray diffractometer to detect the amount of sulfide generated in real time. When the conversion rate is less than 75%, the sulfiding agent addition program is triggered. The magnetic separation efficiency control uses a magnetic susceptibility sensor to detect the metal element content. When the recovery rate is less than 80%, the magnetic separation intensity is optimized.

[0058] The closed-loop control system monitors the conversion rate and recovery efficiency in real time, dynamically adjusts the reagent dosage and magnetic field strength, and ensures that the sorting process is continuously in the optimal operating state.

[0059] Morphological analysis and sediment classification are performed using a particle size classification process. The slurry is separated into coarse particles (>150μm), medium particles (38-150μm), and fine particles (<38μm) using a hydrocyclone. The coarse particles are ultrasonically cleaned with a 5%-8% citric acid solution to remove surface oxides. The medium particles undergo direct morphological transformation, and a 0.1%-0.3% sodium hexametaphosphate dispersant is added to the fine particles to inhibit agglomeration.

[0060] Particle size classification pretreatment eliminates surface coating and agglomeration effects of particles by acid washing coarse particles and dispersing fine particles, thereby improving the uniformity and efficiency of subsequent morphological transformation reactions.

[0061] The high organic matter sludge was pretreated by adding a composite oxidant consisting of potassium persulfate and ferric citrate at a molar ratio of 1:1-2. After the reaction at pH 3.0-3.5, humic acid colloid separation was achieved by centrifugation.

[0062] Composite oxidants pretreat high-organic matter sediments, destroy the heavy metal-organic matter complex structure, reduce organic interference and improve the efficiency of sulfide / metal element generation.

[0063] The treatment of sorting wastewater includes heavy metal removal, salt removal and water recycling. Heavy metal removal uses chelating resin to adsorb and remove heavy metal ions. Salt removal uses membrane separation technology to remove soluble salts. Water recycling reuses the treated water in the mud preparation process to form a circulating water system.

[0064] Chelating resin and membrane separation technology work together to treat wastewater, achieve heavy metal retention and salt removal, form a closed-loop water circulation system, and reduce treatment costs and water consumption.

[0065] The dynamic optimization strategy for the sorting sequence of collaborative sorting collects metal market price data in real time and prioritizes the metal types with the highest unit economic benefits. The dynamic optimization strategy for the sorting sequence is updated every 24 hours and sent to the sorting equipment control terminal.

[0066] The dynamic economic model combines real-time market price data to optimize the sorting sequence, prioritize the recovery of high-economic-value metals, and increase the overall benefits of unit sludge treatment.

[0067] Example 1: Full-process basic implementation

[0068] Step 1: Morphological analysis and sediment classification;

[0069] First, 20 kg of riverbed mud sample was taken and mixed with deionized water to form a homogeneous slurry with a solid-liquid ratio of 1 to 4, with a total mass of 100 kg. The slurry was stirred and homogenized for 30 minutes.

[0070] Next, the occurrence forms of heavy metals in the mud were analyzed by step-by-step chemical extraction method:

[0071] For the determination of carbonate-bound content, 50 g of mud was added with sodium acetate buffer at pH 5.0 and extracted at 25 °C for 6 h with shaking. After centrifugation, the heavy metal content was detected using an inductively coupled plasma spectrometer.

[0072] For the determination of the bound iron and manganese oxide content, a 25% acetic acid solution containing 0.04 mol / L hydroxylamine hydrochloride was added to the residue, and the mixture was extracted in a 96°C water bath for 6 hours. The heavy metal content in the extract was then measured.

[0073] For total content determination, another 50 g of mud was subjected to nitric acid-hydrofluoric acid microwave digestion and then the total amount of heavy metals was determined;

[0074] Then, the mud was separated into coarse, medium and fine particle sizes through a hydrocyclone. The coarse particle size was greater than 150 microns, accounting for 30%; the medium particle size was 38 to 150 microns, accounting for 50%; and the fine particle size was less than 38 microns, accounting for 20%. Finally, the organic matter content of the mud was measured at 4.8% by the potassium dichromate oxidation method, which did not trigger the high organic matter treatment conditions.

[0075] Step 2: morphological transformation processing;

[0076] First, the dosage of the agent is calculated based on the morphological analysis results:

[0077] The carbonate-bound content was found to be 780 mg / kg, the iron and manganese oxide-bound content was 1350 mg / kg, and the total heavy metal content was 3600 mg / kg.

[0078] The morphological conversion coefficient is taken as the base value of 0.8, and the reduction efficiency coefficient is taken as 0.6;

[0079] The dosage of sulfiding agent is calculated as 0.8 times 780 divided by 3600 and then multiplied by the amount of sediment treated, 20 kg, which is 3.68 moles.

[0080] The amount of reducing agent added is calculated as 0.6 times 1350 divided by 3600 and then multiplied by 20 kg, which is 4.50 moles;

[0081] Next, add sulfiding agent and reducing agent to the mud:

[0082] The sulfiding agent is a compound of sodium sulfide and ferrous sulfate prepared in a molar ratio of 1 to 2, with 3.68 moles added;

[0083] The reducing agent is a mixture of ascorbic acid and hydroxylamine hydrochloride in a mass ratio of 3 to 1, with 4.50 mol added;

[0084] Then, the slurry redox potential was controlled to be -280 mV, the reaction temperature was 35 degrees Celsius, and stirring was continued for 120 minutes.

[0085] minutes, which converts carbonate-bound heavy metals into sulfides and iron-manganese oxide-bound heavy metals into elemental metals.

[0086] Step 3, collaborative sorting;

[0087] First, the morphologically transformed slurry is fed into the flotation unit;

[0088] In the first-stage flotation, the pH of the mud was adjusted to 5.0, sodium diethyldithiocarbamate was added as a collector at a concentration of 1.0 mmol / L, the aeration rate was 1.0 cubic meter per minute, and the sulfide concentrate was collected by scraping the bubbles;

[0089] Secondary flotation, adjust the pH to 7.5, add 0.5 mmol / L potassium amyl xanthate, and aerate at 0.8 cubic meters per minute to deeply remove residual sulfides;

[0090] Next, the flotation tailings are fed into the magnetic separation unit:

[0091] The first stage magnetic separation uses a 0.6 Tesla magnetic field to separate ferromagnetic metal elements, including iron, cobalt, and nickel;

[0092] Secondary magnetic separation uses a 1.3 Tesla magnetic field to separate paramagnetic metal elements, including copper, zinc, and cadmium.

[0093] Step 4: Product resource utilization and wastewater treatment;

[0094] First, the sulfide concentrate is dried and sent to a copper smelter with a copper grade of 92.3%; the iron powder obtained by magnetic separation has a purity of 98.5% and is directly used for powder metallurgy; then, the purified mud after sorting is tested to have a total heavy metal content of less than 300 mg / kg and is used for riverbank greening soil improvement; finally, the sorting wastewater is adsorbed with chelating resin to adsorb heavy metal ions, and the conductivity is reduced to below 500 microsiemens per centimeter. The treated water is then reused for the preparation of new batches of mud, realizing a closed-loop cycle.

[0095] Example 2: High organic matter and low pH coupled treatment

[0096] Step 1: Preprocessing and parameter adjustment;

[0097] First, 30 kg of highly contaminated sludge with an organic matter content of 9.8% and a pH of 4.7 was taken and deionized water was added to prepare a slurry with a solid-liquid ratio of 1 to 3; then, a composite oxidant prepared by potassium persulfate and ferric citrate in a molar ratio of 2 to 1 was added at a dosage of 3.2% of the dry weight of the sludge, the pH of the slurry was adjusted to 3.0, and the reaction was carried out at 50 degrees Celsius for 120 minutes; then, humic acid colloids were removed by centrifugation, and the colloid removal rate reached 93%. After pretreatment, the carbonate-bound content dropped from 920 mg / kg to 760 mg / kg.

[0098] Step 2: Dynamic agent addition and morphological transformation;

[0099] First, dynamically adjust the dosage of the agent based on the preprocessed data:

[0100] Because the pH was lower than 6.0, the morphological transformation coefficient decreased by 0.2 from the baseline value of 0.8;

[0101] Because the organic matter content is higher than 5%, the morphological conversion coefficient is increased by another 0.3, and finally taken as 0.9;

[0102] The amount of vulcanizing agent added is calculated as 0.9 multiplied by 760 divided by 4200 and then multiplied by 30 kg, which is 4.89 moles;

[0103] A 5% safety margin was added during the actual addition, and 5.13 mol of sulfiding agent was finally added;

[0104] Next, the slurry redox potential was controlled at negative 270 mV, the reaction temperature was 45 degrees Celsius, and stirring was carried out for 180 minutes. During the process, the sulfide conversion rate was monitored by an online X-ray diffractometer. The initial conversion rate was 72%, which increased to 85% after adding 0.5 moles of sulfiding agent.

[0105] Step 3: Strengthen the sorting process;

[0106] First, the flotation cell adopts the enhanced parameters:

[0107] In the first stage of flotation, the pH was adjusted to 4.5, the collector concentration was increased to 1.5 mmol / L, and the aeration volume was 1.5 cubic meters per minute. The copper recovery rate increased to 87%.

[0108] In the secondary flotation, the pH was adjusted to 7.8 and 0.8 mmol / L potassium isobutyl xanthate was added, and the zinc recovery rate reached 81%;

[0109] Next, the magnetic separation unit uses a gradient magnetic field:

[0110] First-stage magnetic separation, 0.8 Tesla to separate ferromagnetic metals, iron purity reaches 97.5%;

[0111] Secondary magnetic separation, 1.5 Tesla, separates paramagnetic metals, increasing copper purity to 95.5%.

[0112] Step 4: resource recovery and wastewater reuse;

[0113] First, the sulfide concentrate is roasted to produce copper oxide with a purity of 94%, which is used for electrolytic smelting; then, the sorting wastewater is treated with chelating resin, and the copper ion concentration is reduced from 22.5 mg / L to 0.09 mg / L, and then desalinated by electrodialysis, and the conductivity of the produced water is less than 50 microsiemens per centimeter; finally, the treated water is reused for the preparation of new batches of mud, and it still meets the process requirements after 20 cycles.

[0114] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0115] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Intelligent separation technology of heavy metals in sediment based on occurrence state regulation, characterized by: The following steps are involved: S1. Morphological Analysis and Sediment Classification: River sediment samples were prepared into analytical slurry. The carbonate-bound, iron-manganese oxide-bound, organic sulfide-bound, and residual heavy metal contents in the slurry were determined by a stepwise chemical extraction method. Particle size classification was also performed simultaneously, and the total heavy metal content was determined. Mud with an organic matter content exceeding 6% was labeled as high-organic matter sediment. S2. Morphological transformation treatment: adding a sulfiding agent and a reducing agent combination to the slurry, controlling the redox potential to be between -200 mV and -350 mV, so as to transform carbonate-bound heavy metals into sulfides and iron-manganese oxide-bound heavy metals into elemental metals, thereby obtaining a morphologically transformed slurry; S3, collaborative separation: the morphology-transformed mud is sequentially fed into a flotation unit to separate sulfides and a magnetic separation unit to separate metal elements. The remaining material after separation is purified mud, and separation wastewater is generated during the separation process. S4. Product resource utilization: The sulfide concentrate separated by the flotation unit is used as metallurgical raw material, the metal element concentrate separated by the magnetic separation unit is directly recovered, the purified mud is used for soil improvement after meeting environmental protection standards, and the sorting wastewater is recycled after treatment.

2. The intelligent separation technology for heavy metals in sediment based on occurrence state regulation according to claim 1 is characterized in that: The dosage of the vulcanizing agent and reducing agent combination in the morphological transformation treatment is determined by the following formula: in, is the dosage of vulcanizing agent, in moles per kilogram of dry mud; is the morphological transformation coefficient, ranging from 0.6 to 1.0; is the dosage of reducing agent, in moles per kilogram of dry mud; is the reduction efficiency coefficient, ranging from 0.4 to 0.8; is the carbonate-bound heavy metal content, in mg per kilogram; The content of heavy metals bound to iron and manganese oxides, in mg per kilogram; is the total content of heavy metals, in mg per kilogram; It is the amount of sediment treated, in kg.

3. The intelligent separation technology for heavy metals in sediment based on occurrence state regulation according to claim 2 is characterized in that: The morphology conversion coefficient Adjust according to the following rules based on the characteristics of the sediment: When the sediment pH is less than 6.0, The value is reduced by 0.1-0.2, When the organic matter content of sediment is greater than 5%, The value increases by 0.15-0.

25.

4. The intelligent separation technology for heavy metals in sediment based on occurrence state regulation according to claim 1 is characterized in that: The flotation unit operation includes the first and second stages: In the first stage, a dithiocarbamate collector is added to separate the main sulfide at a pH value of 4.5 to 5.5; The second stage adjusts the pH value to 7.0 to 8.0 and supplements xanthate collector to deeply remove residual sulfide.

5. The intelligent separation technology for heavy metals in sediment based on occurrence state regulation according to claim 1 is characterized in that: The operation of the magnetic separation unit includes a first gradient sorting and a second gradient sorting, wherein the first gradient sorting uses a magnetic field strength of 0.5 to 0.8 T to separate ferromagnetic metal elements, and the second gradient sorting uses a magnetic field strength of 1.2 to 1.5 T to separate paramagnetic metal elements.

6. The intelligent separation technology for heavy metals in sediment based on occurrence state regulation according to claim 1 is characterized in that: A closed-loop control system is set up in the morphological transformation processing and coordinated sorting, and the closed-loop control system includes morphological transformation monitoring and magnetic separation efficiency regulation. The morphological transformation monitoring detects the amount of sulfide generated in real time through an X-ray diffractometer, and triggers a sulfiding agent addition program when the conversion rate is less than 75%; the magnetic separation efficiency regulation detects the metal element content through a magnetic susceptibility sensor, and optimizes the magnetic separation intensity when the recovery rate is less than 80%.

7. The intelligent separation technology for heavy metals in sediment based on occurrence state regulation according to claim 1 is characterized in that: The morphological analysis and sediment classification particle size classification treatment is to separate the mud into coarse particles > 150 μm, medium particles 38-150 μm and fine particles < 38 μm by a hydrocyclone. The coarse particles are ultrasonically cleaned with a citric acid solution having a mass concentration of 5%-8% to remove surface oxides. The medium particles are directly subjected to the morphological transformation treatment. The fine particles are added with a sodium hexametaphosphate dispersant having a mass concentration of 0.1%-0.3% to inhibit agglomeration.

8. The intelligent separation technology for heavy metals in sediment based on occurrence state regulation according to claim 1 is characterized in that: The high-organic matter sludge is pretreated, and a composite oxidant consisting of potassium persulfate and ferric citrate is added at a molar ratio of 1:1-2. After the reaction is carried out under a pH value of 3.0-3.5, humic acid colloid separation is achieved by centrifugation.

9. The intelligent separation technology for heavy metals in sediment based on occurrence state regulation according to claim 1 is characterized in that: The sorting wastewater treatment includes heavy metal removal, salt removal and water recycling. The heavy metal removal uses chelating resin to adsorb and remove heavy metal ions. The salt removal uses membrane separation technology to remove soluble salts. The water recycling reuses the treated water in the mud preparation process to form a circulating water system.

10. The intelligent separation technology for heavy metals in sediment based on occurrence state regulation according to claim 1 is characterized in that: The dynamic optimization strategy for the sorting sequence of the collaborative sorting collects metal market price data in real time and gives priority to sorting metal types with high unit economic benefits; the dynamic optimization strategy for the sorting sequence is updated every 24 hours and sent to the sorting equipment control terminal.

Images