Harmless treatment process for nonferrous metal hazardous waste

Abstract

The invention discloses an innocent treatment process for non-ferrous metal hazardous waste, relates to the field of metal treatment, and aims to solve the problems of low heavy metal recovery rate, poor solidified body stability, high secondary pollution risk and the like caused by insufficient dispersion and synergism of a conventional sectional treatment process technology. The invention provides a pretreatment-core treatment-post-treatment whole-process synergistic process. In the pretreatment stage, through the combination of biological adsorption and chemical precipitation, organic matters are decomposed, and heavy metals are preliminarily fixed; in the core treatment stage, plasma is adopted to melt and decompose organic pollutants, and heavy metal is reduced and recovered through a microwave molten pool; and in the post-treatment stage, hydroxyapatite mineralization and vitrification melting are coupled to form a stable solidified body. According to the technology, by limiting key parameters such as biological adsorption time, microwave molten pool temperature and vitrification base material proportion, efficient recovery of the heavy metal, improvement of compressive strength of a solidified body and reduction of the leaching rate of the heavy metal are achieved, and the cooperative treatment problem of heavy metal immobilization-organic matter decomposition-long-term stability is comprehensively solved.

Description

Technical Field

[0001] The present invention relates to the field of metal processing, and in particular to a harmless treatment process for non-ferrous metal hazardous waste. Background Art

[0002] In the field of harmless treatment of non-ferrous metal hazardous waste, existing technologies mainly adopt a single or simple combination of process routes. Microbial adsorption or chemical precipitation is usually used alone in the pretreatment stage: although microbial adsorption can reduce the concentration of heavy metals by utilizing the activity of bacterial strains, there is a problem of failure after adsorption saturation, and the decomposition ability of high-concentration organic matter (such as polychlorinated biphenyls) in hazardous waste is limited; although chemical precipitation can quickly remove heavy metals, traditional agents (such as sodium sulfide) have weak binding ability with heavy metals and need to be excessively added (usually 2-3 times the stoichiometric ratio), resulting in a high amount of sulfur-containing sludge and a high risk of secondary pollution. A single technology is often used in the core treatment stage: plasma melting is mainly used to decompose organic pollutants, but the efficiency of heavy metal reduction is low, and additional reducing agents need to be added; although microwave melting pools can efficiently reduce heavy metals, they need to heat the slag phase separately, which consumes a lot of energy. The post-processing stage often uses a single solidification technology: hydroxyapatite mineralization fixes heavy metals only through chemical bonding, with weak physical encapsulation of inorganic residues and a high risk of long-term leaching. While vitrification melting can form a stable glass, it lacks a chemical bonding effect on already formed heavy metal crystals (such as pyromorphite). Furthermore, the existing process lacks parameter connection design between the various stages. The pre-treatment filter cake must be dried before entering the melting stage, and the plasma slag phase must be cooled and then reheated to the molten pool temperature, resulting in energy waste. Secondary pollution, such as dust diffusion and filtrate leakage, is prone to occur during the storage and transportation of intermediate materials (such as filter cake and slag phase).

[0003] The above-mentioned existing technologies have the following prominent problems: First, the limitation of the single technology in the pretreatment stage makes it impossible to achieve the simultaneous reduction of heavy metal concentration and digestion of organic matter, making it difficult to meet the demand for low-pollution-load raw materials in subsequent core treatment; Second, the separation of organic decomposition and metal recovery technology in core treatment leads to limited pollutant decomposition efficiency and heavy metal recovery rate; Third, the "chemical bonding" or "physical packaging" capabilities of the single solidification technology in post-treatment are insufficient to ensure the long-term stability of the solidified body; Fourth, the discontinuous parameters of the entire process lead to excessive energy consumption, and the exposure of intermediate materials increases the risk of secondary pollution. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a harmless treatment process for non-ferrous metal hazardous waste to solve one or more problems in the prior art.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A harmless treatment process for non-ferrous metal hazardous wastes comprises the following steps:

[0007] S1:

[0008] (a) Crush the hazardous waste to a particle size of ≤5 mm and adjust the moisture content to 40%-60% after homogenization.

[0009] (b) A composite microbial agent is used for biosorption, wherein the composite agent is composed of sulfate-reducing bacteria (55%-65%), methanogens (25%-35%), and Bacillus subtilis (5%-15%), and the amount of the agent added is 0.4%-0.6% of the mass of the hazardous waste.

[0010] (c) After biosorption, chemical precipitation is performed using sodium diethyldithiocarbamate (DDTC) containing a thiol functional group at a stoichiometric ratio of 1.1-1.3 times the residual concentration of the heavy metals. After solid-liquid separation, a filter cake with a moisture content of ≤60% is obtained.

[0011] S2:

[0012] (a) The pretreated filter cake is subjected to plasma melting to decompose the organic pollutants. The plasma temperature is 1600-1800°C, the reaction atmosphere is a reducing atmosphere (O2 concentration ≤ 5%), and the hazardous waste residence time is 3-5s.

[0013] (b) The high-temperature slag phase (temperature ≥ 1000°C) produced by plasma melting directly enters the microwave melting pool, and the heavy metals are reduced by microwave-assisted reduction with a frequency of 2.45 GHz. The melting pool temperature is 1150-1350°C, and the amount of reducing agent (coke powder) added is 2%-6% of the mass of the slag phase.

[0014] S3:

[0015] (a) The slag phase produced by the microwave melting pool is mineralized with hydroxyapatite, the amount of hydroxyapatite added is 8%-17% of the mass of the slag phase, the moisture content after mixing is 18%-27%, and the slag phase is cured at room temperature for 5-9 days.

[0016] (b) The mineralized slag phase is mixed with a vitrified matrix (SiO2:Al2O3:CaO=5.5-6.5:1.5-2.5:1.5-2.5, with the addition amount being 35%-45% of the mass of the mineralized slag phase), melted at 1350-1550°C, and then quenched in water (cooling rate ≥80°C / s), mixed with 4%-6% cement, and pressed into shape (pressure 8-12 MPa).

[0017] Furthermore, the reaction conditions of the biosorption are: temperature 33-37° C., pH=6.3-7.7, stirring rate 70-110 rpm, and reaction time 10-26 h.

[0018] Furthermore, the reaction conditions of the chemical precipitation are: pH = 7.8-9.2, stirring rate 130-170 rpm, reaction time 25-35 min. Solid-liquid separation uses a plate and frame filter press (pressure 0.7-0.9 MPa), and the heavy metal concentration of the filtrate is ≤ 0.5 mg / L.

[0019] Furthermore, the plasma-melted gaseous product is subjected to a quenching tower (1600-1800° C. to 180-220° C., residence time <2.5 s) + activated carbon adsorption + bag dust removal treatment.

[0020] Furthermore, the reaction time of the microwave melting pool is 13-22 minutes.

[0021] Furthermore, the crystals generated by the mineralization of hydroxyapatite include pyromorphite or hydroxyapatite.

[0022] Furthermore, the holding time of the vitrification melting is 0.8-1.2h.

[0023] Furthermore, the particle size of the reducing agent coke powder is ≤2mm.

[0024] Furthermore, the particle size of the solidified body after water quenching is ≤50 mm.

[0025] Furthermore, the non-ferrous metal hazardous waste includes sludge residue containing heavy metals (Pb, Cu, Ni) and organic hazardous waste containing polychlorinated biphenyls and dioxins.

[0026] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0027] (1) The synergistic combination of "biosorption-chemical precipitation" in the pretreatment stage is superior to the treatment method of a single technology.

[0028] Through the combination of composite microbial agents (sulfate-reducing bacteria, methanogens, Bacillus subtilis) and DDTC chemical precipitation, the adsorption capacity of microorganisms (reducing heavy metal concentrations) and the decomposition capacity of organic matter (avoiding excessive viscosity) are utilized, and the efficient precipitation of DDTC (for residual high concentrations of heavy metals) is used to solve the problems of easy saturation failure of single biological treatment and high consumption of single chemical treatment agents. The composite pretreatment effect of "heavy metal concentration gradient reduction + simultaneous digestion of organic matter" is achieved, providing raw materials with low pollution load for subsequent core treatment.

[0029] (2) The core processing technology is the cross-coupling of “plasma melting-microwave melting pool” to improve the efficiency of pollutant decomposition and resource recovery.

[0030] While plasma melting (1600-1800℃ high temperature + reducing atmosphere) decomposes organic pollutants (such as dioxins), the generated high-temperature slag phase (≥1000℃) directly enters the microwave melting pool (2.45GHz frequency + 1150-1350℃), and uses the molecular resonance effect of microwaves and heavy metal oxides to accelerate the reduction reaction. This not only avoids the energy loss of plasma slag phase cooling, but also improves the heavy metal recovery rate through microwave assistance (30%-50% higher than traditional melting pools), achieving the dual goals of "complete decomposition of organic pollutants + efficient recovery of heavy metals".

[0031] (3) Post-treatment: Double solidification of “hydroxyapatite mineralization-vitrification melting” to enhance the long-term stability of the residue.

[0032] Hydroxyapatite mineralization (forming stable crystals such as pyromorphite) fixes heavy metals through chemical bonding, and vitrification melting physically wraps the residue through amorphous glass. The combination of the two forms a double barrier of "chemical bonding-physical wrapping". Compared with single mineralization or vitrification technology, it significantly reduces the risk of heavy metal leaching (leaching rate ≤ 0.05 mg / L) and extends the stability period of the solidified body to more than 300 years.

[0033] (4) Continuous design of parameters throughout the entire process to reduce energy consumption and the risk of secondary pollution.

[0034] The pretreated filter cake directly enters plasma melting (no drying required), the plasma slag phase directly enters the microwave melting pool (retaining high temperature), and the mineralized slag phase is directly used for vitrification melting (reducing intermediate storage). Through the connection design of parameters in each stage (such as moisture content 40%-60% → plasma temperature 1600-1800℃ → microwave melting pool temperature 1150-1350℃), the energy loss of "cooling-reheating" in the traditional process is avoided (energy consumption is reduced by 20%), and the secondary pollution caused by exposure of intermediate materials (such as dust diffusion and filtrate leakage) is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic flow chart of the treatment process in the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and exemplary explanations. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not intended to limit the conditions for the implementation of the present invention. Therefore, they have no technical significance. Any modification of the structure, change in the proportion relationship or adjustment of the size should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose of the present invention.

[0037] Application Overview

[0038] In the field of harmless treatment of non-ferrous metal hazardous waste, the industry currently mainly adopts a staged or single technology combination treatment model. The pretreatment stage mostly relies on a single technology: some processes only reduce the concentration of heavy metals through microbial adsorption, but they are easily ineffective due to saturated adsorption of bacterial strains, and their ability to decompose high-concentration organic matter (such as polychlorinated biphenyls) is limited; other processes simply use chemical precipitation. Although they can quickly remove heavy metals, traditional agents (such as sodium sulfide) need to be added in excess (usually 2-3 times the stoichiometric ratio), resulting in a high amount of sulfur-containing sludge and a high risk of secondary pollution. The core treatment stage often separates organic decomposition from metal recovery: plasma melting is mainly used for high-temperature decomposition of organic pollutants (such as dioxins), but the efficiency of heavy metal reduction is low and additional reducing agents need to be added; although microwave melting pools can efficiently reduce heavy metals, they need to heat the slag phase separately, which consumes a lot of energy. A single solidification technology is often used in the post-disposal stage: hydroxyapatite mineralization only fixes heavy metals through chemical bonding, has weak physical packaging capabilities for inorganic residues, and has a high risk of long-term leaching; although vitrification melting can form a stable glass body, it has insufficient chemical bonding effects on the already generated heavy metal crystals (such as pyromorphite). In addition, there is a lack of parameter connection design between the various stages of the conventional process. The pre-treated filter cake needs to be dried before entering the melting stage, and the plasma slag phase needs to be cooled and reheated to the molten pool temperature, resulting in energy waste; during the storage and transportation of intermediate materials (such as filter cakes and slag phases), secondary pollution such as dust diffusion and filtrate leakage is prone to occur. Due to the scattered technical means and lack of synergy, the above conventional schemes are difficult to achieve the comprehensive goals of "efficient fixation of heavy metals - complete decomposition of organic matter - resource recovery - long-term stability" at the same time.

[0039] Comprehensive description

[0040] The present invention relates to a harmless treatment process for non-ferrous metal hazardous waste, suitable for treating sludge / slag containing heavy metals (such as Pb, Cu, and Ni) and hazardous waste containing organic pollutants such as polychlorinated biphenyls and dioxins. The technical solution of the present invention is described in detail below, combining specific process steps:

[0041] 1. Preprocessing stage

[0042] The core purpose of pretreatment is to reduce the concentration of heavy metals in hazardous waste, eliminate organic matter and adjust the material state, so as to provide stable raw materials with low pollution load for subsequent core treatment. The specific operations are as follows:

[0043] Crushing and homogenization:

[0044] Non-ferrous metal hazardous waste to be treated (including heavy metal-containing sludge / slag and organic hazardous waste containing polychlorinated biphenyls and dioxins) is crushed using a jaw crusher or hammer crusher, with the particle size controlled to ≤5mm. The crushed material enters a homogenization mixing tank, where it is mechanically agitated (at a rate of 100-150rpm) for 30-60 minutes to ensure uniform composition. The moisture content is then adjusted to 40%-60% by adding water or using a centrifugal dehydrator to balance microbial activity with the thermal efficiency of the subsequent plasma fusion process.

[0045] Biosorption treatment:

[0046] The homogenized material is transferred to a bioreactor, and a composite microbial agent (accounting for 0.4%-0.6% of the mass of the hazardous waste) is added. The composite microbial agent is composed of sulfate-reducing bacteria (SRB, accounting for 55%-65% of the total agent), methanogens (MPB, accounting for 25%-35%) and Bacillus subtilis (BS, accounting for 5%-15%). The reaction conditions of bioadsorption are controlled as follows: temperature 33-37°C (maintained by heating or cooling with a water bath jacket), pH = 6.3-7.7 (adjusted by adding dilute hydrochloric acid or sodium hydroxide solution), stirring rate 70-110rpm, reaction time 10-26h. During this process, SRB adsorbs heavy metal ions (such as Pb) by secreting extracellular polymers. 2 +、Cu 2+ ), MPB decomposes organic pollutants (such as polychlorinated biphenyls) to produce methane, and BS secretes proteases to reduce the viscosity of the material. The three work together to achieve the initial fixation of heavy metals and the digestion of organic matter.

[0047] Chemical precipitation and solid-liquid separation:

[0048] After biosorption, the material is transferred to a chemical precipitation tank, where sodium diethyldithiocarbamate (DDTC), containing a thiol functional group, is added at a stoichiometric ratio of 1.1-1.3 times the residual heavy metal concentration (calculated and determined by real-time monitoring of heavy metal concentrations using an atomic absorption spectrometer). The chemical precipitation reaction conditions are: pH = 7.8-9.2 (adjusted by adding lime milk), a stirring rate of 130-170 rpm, and a reaction time of 25-35 minutes. After completion of the reaction, solid-liquid separation is performed using a plate and frame filter press (optional model XMYJ, operating pressure 0.7-0.9 MPa), resulting in a filter cake with a moisture content of ≤60%. The filtrate, after testing to a heavy metal concentration of ≤0.5 mg / L, can be fed into the sewage treatment system.

[0049] 2. Core processing stage

[0050] The core treatment achieves complete decomposition of organic pollutants and efficient recovery of heavy metals through the coupling technology of high-temperature plasma melting and microwave-assisted reduction.

[0051] Plasma melting decomposition of organic pollutants:

[0052] The filter cake obtained from pretreatment is directly transferred to a plasma melting furnace (using a DC plasma generator with a power of 500-1000kW) for melting in a reducing atmosphere (O2 concentration ≤5%, maintained by the introduction of nitrogen or carbon monoxide). The plasma temperature is controlled at 1600-1800°C, and the material resides in the furnace for 3-5 seconds. Under these conditions, organic pollutants (such as dioxins) are decomposed into harmless gases such as CO2 and H2O, while heavy metals (such as Pb, Cu, and Ni) are converted into oxides and enter the slag phase.

[0053] Microwave melting pool assisted reduction of heavy metals:

[0054] The high-temperature slag phase (≥1000°C) produced by plasma melting is fed directly into a microwave melting pool (frequency 2.45 GHz, power 200-500 kW) via a chute, eliminating the energy loss associated with slag cooling. Coke powder with a particle size ≤2 mm (accounting for 2%-6% of the slag mass) is added to the melting pool as a reducing agent. The temperature is controlled at 1150-1350°C, and the reaction time is 13-22 minutes. The high-frequency electromagnetic field of the microwave resonates with the heavy metal oxide molecules, accelerating the reaction rate between the reducing agent and the heavy metal oxides. Ultimately, the metal phase (such as Pb and Cu) settles to the bottom of the melting pool in liquid form, with a recovery rate of ≥95% (determined by gravimetric or compositional analysis).

[0055] 3. Post-processing stage

[0056] Post-treatment uses the dual solidification technology of "mineralization-vitrification" to ensure the long-term stability of the residue and meet the requirements of safe landfill or resource utilization.

[0057] Hydroxyapatite mineralization:

[0058] The slag phase (mainly composed of heavy metal silicates) discharged from the microwave melting pool is transferred to a mineralizing mixer, where hydroxyapatite powder (particle size ≤ 0.1mm) is added at a rate of 8%-17% of the slag phase mass, and water is added to adjust the moisture content of the mixture to 18%-27%. After uniform mixing, the material is transferred to a curing tank and cured at room temperature (20-30°C) for 5-9 days to reduce the concentration of heavy metal ions (such as Pb 2+ ) reacts with hydroxyapatite to form stable crystals (such as pyromorphite Pb 10 (PO4)6Cl2 or hydroxymorphite Pb 10 (PO4)6(OH)2), fixes heavy metals through chemical bonding.

[0059] Vitrification melting and molding:

[0060] The mineralized slag is mixed with a vitrified matrix (SiO2:Al2O3:CaO = 5.5-6.5:1.5-2.5:1.5-2.5, representing 35%-45% of the mineralized slag mass) and then placed in a vitrification melting furnace (1350-1550°C) for 0.8-1.2 hours, melting the material to form an amorphous glass. The molten material is then rapidly quenched in water (cooling rate ≥80°C / s) and crushed to a particle size ≤50mm. The material is then mixed with 4%-6% ordinary Portland cement and pressed into shape using a hydraulic press (pressure 8-12MPa). The resulting solidified product exhibits a compressive strength ≥10MPa (determined by a pressure tester) and a heavy metal leaching rate ≤0.05mg / L (tested in accordance with the "Hazardous Waste Identification Standard - Leaching Toxicity Identification" GB 5085.3-2007). It is safe for landfill or use as construction aggregate.

[0061] By integrating parameters across pretreatment, core treatment, and post-treatment stages (e.g., direct plasma melting of pretreatment filter cakes and direct microwave melting of plasma slag), this process avoids the energy losses associated with the traditional "cooling-reheating" process (reducing energy consumption by 20% compared to traditional processes) while also minimizing the risk of secondary contamination from exposed intermediate materials. The synergistic effects of various technical approaches at each stage (e.g., the complementary effects of biosorption and chemical precipitation, the coupling of plasma melting and microwave reduction, and the dual solidification of mineralization and vitrification) ultimately achieve the harmless treatment of non-ferrous metal hazardous waste and the efficient recovery of resources.

[0062] To verify the actual impact of this process's key parameters on the final treatment outcome, the following experiment was designed based on key control parameters from the pretreatment, core treatment, and post-treatment stages of the process. The experiment used "heavy metal recovery rate," "solidified body compressive strength," and "heavy metal leaching rate" as performance evaluation indicators. Leaching rate was determined using the "Hazardous Waste Identification Standard - Leaching Toxicity Identification" (GB5085.3-2007), compressive strength was determined using the "Standard for Test Methods for Mechanical Properties of Ordinary Concrete" (GB / T 50081-2019), and heavy metal recovery was determined using the gravimetric method.

[0063] Experimental design description

[0064] The following three key variables are selected as experimental factors (all of which are parameters that need to be strictly controlled in the process):

[0065] Variable A: biosorption reaction time in the pretreatment stage (original process control range: 10-26h);

[0066] Variable B: microwave melting pool temperature during the core treatment phase (original process control range: 1150-1350°C);

[0067] Variable C: The proportion of vitrified substrate in the post-processing stage (original process control range: 35%-45%).

[0068] The experiment set up 10 groups, including:

[0069] Conventional group (groups 1-5): variables A, B, and C were all within the original process control range;

[0070] Out-of-range group (6-9 groups): at least one variable exceeds the original process control range;

[0071] Blank control group (10 groups): using traditional segmented treatment process (pretreatment only chemical precipitation, core treatment only plasma melting, post-treatment only vitrification melting).

[0072] All experimental groups maintained consistent parameters, including the hazardous waste feedstock (containing 28.3 g / kg of Pb, 12.7 g / kg of Cu, and 0.5 ng / g of dioxins), the microbial inoculant ratio (SRB:MPB:BS = 60:30:10), and the plasma melting temperature (1700°C). The experimental results were evaluated using a weighted score (weights: heavy metal recovery rate 40%, compressive strength 30%, and leaching rate 30%, with the leaching rate calculated as the inverse value (i.e., 1 - leaching rate / 0.1).

[0073] Experimental records and results

[0074]

[0075] Experimental results analysis

[0076] The conventional groups (groups 1-5) all achieved heavy metal recovery rates ≥95%, compressive strength ≥11.2 MPa, and leaching rates ≤0.05 mg / L. These comprehensive scores were significantly higher than those of the out-of-range groups (groups 6-9) and the blank control group (group 10), confirming the necessity of the original process's parameter limits for variables A, B, and C to ensure treatment effectiveness. Group 2 (variables A = 18 h, B = 1300 ° C, C = 42%) achieved the highest comprehensive score (95.3), indicating a synergistic effect between the parameters and a lack of a strict linear relationship between performance and a single variable. The out-of-range groups (groups 6-9) experienced a 3%-6% decrease in recovery, a 1.4-4.6 MPa decrease in compressive strength, and a 0.03-0.07 mg / L increase in leaching rate due to at least one parameter deviating from the original process range. The blank control group, which used a traditional staged process, had significantly lower values for all three indicators than the conventional group, further demonstrating the effectiveness of this process technology.

[0077] Through the above experiments, it can be concluded that the parameter limit range of variables A, B, and C in the original process is the key to ensuring the comprehensive goals of "efficient recovery of heavy metals - stable solidification - low leaching risk", which has clear practical significance.

[0078] Weighted scoring analysis of experimental data and molecular-level mechanisms

[0079] In the experiment, the comprehensive scores of the conventional groups (Groups 1-5) were significantly higher than those of the other groups. Group 2 (variables A = 18h, B = 1300°C, C = 42%) ranked first with 95.3 points. This result can be explained by the influence of each variable on the molecular-level reaction and the synergistic effect.

[0080] 1. Molecular mechanism of variable A (biosorption time)

[0081] The core of the biosorption stage is the molecular interaction between the active substances secreted by the composite bacteria (SRB, MPB, BS) and heavy metal ions. The extracellular polymers (EPS) secreted by SRB contain functional groups such as carboxyl (-COOH) and hydroxyl (-OH). The O atoms on their molecular chains interact with Pb through lone pairs of electrons. 2+ 、Cu 2+ Forming coordination bonds (such as Pb 2+ -OOC-), achieving initial fixation of heavy metals. MPB decomposes organic matter (such as polychlorinated biphenyls) to produce small acids such as acetic acid, lowering the solution pH to 6.3-7.7. This promotes the protonation of the carboxyl groups of EPS molecules (-COOH → -COO-), enhancing the electrostatic attraction to metal ions. The protease secreted by BS hydrolyzes proteinaceous viscous substances, reducing the steric hindrance between EPS and metal ions and improving mass transfer efficiency.

[0082] When the adsorption time is too short (e.g., 5-8 hours in Groups 6 and 8), EPS secretion by SRB does not reach its peak (it takes approximately 12 hours to enter the stable phase), MPB decomposition of organic matter is incomplete (high dioxin residues), resulting in insufficient coordination sites between EPS and metal ions, and heavy metal recovery rates are only 91.5%-92.1%. When the adsorption time is too long (e.g., 28-30 hours in Groups 7 and 9), SRB enters the decline phase, EPS desorption begins (coordination bond cleavage), and MPB metabolites (such as methane) accumulate, inhibiting SRB activity, resulting in a recovery rate of 93.4%-94.8%. The conventional group (10-26 hours) coincides with the logarithmic growth phase of SRB (12-24 hours), allowing EPS secretion and metal coordination to reach a dynamic equilibrium, resulting in a stable recovery rate of 95.2%-97.8%.

[0083] 2. Molecular Energy Transfer of Variable B (Microwave Melting Pool Temperature)

[0084] The core of microwave melting pool is the dielectric coupling between microwave field and heavy metal oxide molecules. The dielectric constant (ε') of metal oxides such as PbO and CuO increases with the increase of temperature (ε'≈8 at 1150℃, ε'≈12 at 1350℃), and the energy coupling efficiency with microwaves is enhanced. The high frequency electromagnetic field of microwaves (2.45GHz) makes the dipoles of oxide molecules (such as PbO) 2 +-O 2-) produces high frequency vibration (about 2.45×10 9 times / s), generating Joule heat and accelerating the reduction reaction of C atoms in coke powder with metal oxides (such as PbO+C→Pb+CO↑).

[0085] When the temperature is too low (e.g., 1050-1100°C in Groups 6 and 8), the dipole vibration frequency of the oxide molecules is low, reducing the energy transfer efficiency with the microwave, insufficient carbon atom activity, and a slow reduction reaction rate (reaction time needs to be extended to at least 30 minutes), resulting in a decrease in recovery rate. When the temperature is too high (e.g., 1400-1450°C in Groups 7 and 9), although the boiling point of Pb (1749°C) is not reached, the thermal motion of Pb atoms is intensified, causing some Pb to diffuse into the gas phase in an atomic state (loss rate of approximately 2%-3%). Simultaneously, the melt viscosity decreases (η<0.1 Pa·s), causing the metal phase to easily mix with the slag phase, reducing separation efficiency. The temperature range of the conventional group (1150-1350°C) achieves the best match between dipole vibration and reduction reaction, with a metal recovery rate of ≥95%.

[0086] 3. Molecular Network Construction of Variable C (Glassified Substrate Ratio)

[0087] The core function of the glass matrix (SiO2:Al2O3:CaO=5.5-6.5:1.5-2.5:1.5-2.5) is to form silicon-oxygen tetrahedron ([SiO4] 4- ) network, encapsulating heavy metal crystals (such as pyromorphite Pb 10 (PO4)6Cl2). SiO2 provides [SiO4] 4- Structural unit, Al2O3 through [AlO4] 5- Replacement part [SiO4] 4- , reducing the network negative charge density; Ca 2+ As a network modifier, it fills the tetrahedral gaps and stabilizes the network structure.

[0088] When the substrate ratio is too low (such as 30-32% in groups 6 and 8), [SiO4] 4- The network is sparse (Si-O bond density <5×10 20 pieces / cm 3 ), heavy metal crystals are easily exposed to the leachate (H2O molecules penetrate through the pores and interact with Pb 2+ Ion exchange occurs), the leaching rate rises to 0.09-0.11 mg / L; if the ratio is too high (such as 48-50% in groups 7 and 9), the melt viscosity increases (η>0.5 Pa·s), micro cracks (crack width>1μm) are generated due to the temperature difference between the inside and outside during cooling, and the compressive strength drops to 8.9-10.8MPa. The base material ratio of the conventional group (35%-45%) makes [SiO4] 4- The network density is moderate (Si-O bond density ≈ 7×1020 pieces / cm 3 ), can be chemically bonded (Pb 2+ With [SiO4] 4- It can fix heavy metals through electrostatic effect and block the penetration of H2O molecules through physical packaging (network pore size <0.1μm), with the final leaching rate ≤0.05mg / L and compressive strength ≥11.2MPa.

[0089] 4. Synergistic Effect of Comprehensive Performance

[0090] The high score of Group 2 (A = 18h, B = 1300℃, C = 42%) is due to the molecular-level synergy of the three variables: 18h of biosorption makes EPS secretion and metal coordination reach the peak (92% utilization of coordination sites); 1300℃ microwave temperature makes the PbO4 molecule dipole vibration efficiency the highest (85% energy conversion rate), and the reduction reaction rate increases by 30%; 42% substrate ratio makes [SiO4] 4- The network density is optimal (Si-O bond density 7.2×10 20 pieces / cm 3 This synergistic effect resulted in the optimal heavy metal recovery rate (97.8%), compressive strength (13.5 MPa), and leaching rate (0.03 mg / L).

[0091] The out-of-range group deviated from a single variable, which destroyed the reaction balance at the molecular level (e.g., variable A was too short, resulting in insufficient coordination sites, and variable B was too high, resulting in volatilization of Pb atoms), and ultimately the performance declined. The blank control group lacked the synergy of biosorption and microwave reduction (relying only on chemical precipitation and plasma melting), and the reaction path at the molecular level was short (e.g., Pb 2+ The cells were only fixed by sulfide precipitation and did not undergo the dual enrichment of EPS coordination and microwave reduction, so the various indicators were significantly lower than those of the conventional group.

[0092] In summary, the limited range of experimental variables (A = 10-26h, B = 1150-1350°C, C = 35%-45%) is the key to ensuring the efficiency and synergy of the molecular-level reaction, and directly determines the quality of the final treatment effect.

[0093] Example

[0094] Example 1

[0095] 100 kg of hazardous waste containing 28.3 g / kg of Pb, 12.7 g / kg of Cu, and 0.5 ng / g of dioxin (I-TEQ) was crushed to a particle size of ≤5 mm using a jaw crusher. The mixture was then transferred to a homogenization mixing tank and mechanically stirred at 150 rpm for 30 minutes, adjusting the moisture content to 45%. The mixture was then transferred to a bioreactor, where 2 kg of a composite microbial inoculant (SRB:MPB:BS) was added in a ratio of 60:30:10. The reaction temperature was maintained at 35°C, and the biosorption reaction was carried out for 12 hours. After completion of the reaction, a thiol-containing precipitant (0.8% of the hazardous waste mass) was added to the tank, stirring was continued for 1 hour, and the filter cake was obtained through solid-liquid separation using a plate and frame filter press.

[0096] The filter cake is placed in a plasma melting furnace, nitrogen is introduced to maintain a reducing atmosphere, and the furnace temperature is controlled at 1700°C for 2 hours to decompose organic pollutants and allow heavy metal oxides to enter the slag phase. The molten slag phase enters the microwave melting bath through a chute, where coke powder (5% of the slag mass) is added. The microwave melting bath temperature is controlled at 1200°C for 1.5 hours of reduction. The liquid metal phase is then recovered by sedimentation, and the remaining slag phase is transferred to a mineralizing mixer.

[0097] Hydroxyapatite powder (12% of the slag mass) is added to a mineralizing mixer and mixed at 80 rpm for 30 minutes. The mixture is then transferred to a curing tank and cured at room temperature for 48 hours. The cured mineralized slag is then mixed with a vitrified matrix (SiO2:Al2O3:CaO = 6:2:2, representing 38% of the total material) and fed into a vitrification furnace. The temperature is controlled at 1500°C and the mixture is melted for 1 hour to form a vitreous body. The vitreous body is then quenched and crushed to a particle size of ≤3 mm. The vitreous body is then mixed with Portland cement (20% of the vitreous body mass) and pressed into a solidified body using a hydraulic press at 15 MPa.

[0098] Example 2

[0099] 100 kg of hazardous waste containing 28.3 g / kg of Pb, 12.7 g / kg of Cu, and 0.5 ng / g of dioxin (I-TEQ) was crushed to a particle size of ≤5 mm using a jaw crusher. The mixture was then transferred to a homogenization mixing tank and mechanically stirred at 150 rpm for 30 minutes, adjusting the moisture content to 45%. The mixture was then transferred to a bioreactor, where 2 kg of a composite microbial inoculant (SRB:MPB:BS) was added in a ratio of 60:30:10. The reaction temperature was maintained at 35°C, and the biosorption reaction was carried out for 18 hours. After completion of the reaction, a thiol-containing precipitant (0.8% of the hazardous waste mass) was added to the tank, stirring was continued for 1 hour, and solid-liquid separation was performed using a plate and frame filter press to obtain a filter cake.

[0100] The filter cake is placed in a plasma melting furnace, nitrogen is introduced to maintain a reducing atmosphere, and the furnace temperature is controlled at 1700°C for 2 hours to decompose organic pollutants and allow heavy metal oxides to enter the slag phase. The molten slag phase enters the microwave melting bath through a chute, where coke powder (5% of the slag phase mass) is added. The microwave melting bath temperature is controlled at 1300°C for 1.5 hours of reduction. The liquid metal phase is then recovered by sedimentation, and the remaining slag phase is transferred to a mineralizing mixer.

[0101] Hydroxyapatite powder (12% of the slag mass) is added to a mineralizing mixer and mixed at 80 rpm for 30 minutes. The mixture is then transferred to a curing tank and cured at room temperature for 48 hours. The cured mineralized slag is then mixed with a vitrified matrix (SiO2:Al2O3:CaO = 6:2:2, representing 42% of the total material) and fed into a vitrification furnace, where it is melted at 1500°C for 1 hour to form a vitreous body. The vitreous body is then quenched and crushed to a particle size of ≤3 mm, mixed with Portland cement (20% of the vitreous body mass), and pressed into a solidified body using a hydraulic press at 15 MPa.

[0102] Example 3

[0103] 100 kg of hazardous waste containing 28.3 g / kg of Pb, 12.7 g / kg of Cu, and 0.5 ng / g of dioxin (I-TEQ) was crushed to a particle size of ≤5 mm using a jaw crusher. The mixture was then transferred to a homogenization mixing tank and mechanically stirred at 150 rpm for 30 minutes, adjusting the moisture content to 45%. The mixture was then transferred to a bioreactor, where 2 kg of a composite microbial inoculant (SRB:MPB:BS) was added in a ratio of 60:30:10. The reaction temperature was maintained at 35°C, and the biosorption reaction was carried out for 24 hours. After completion of the reaction, a thiol-containing precipitant (0.8% of the hazardous waste mass) was added to the tank, stirring was continued for 1 hour, and the filter cake was obtained through solid-liquid separation using a plate and frame filter press.

[0104] The filter cake is placed in a plasma melting furnace, nitrogen is introduced to maintain a reducing atmosphere, and the furnace temperature is controlled at 1700°C for 2 hours to decompose organic pollutants and allow heavy metal oxides to enter the slag phase. The molten slag phase enters the microwave melting bath through a chute, where coke powder (5% of the slag mass) is added. The microwave melting bath temperature is controlled at 1180°C for 1.5 hours of reduction. The liquid metal phase is then recovered by sedimentation, and the remaining slag phase is transferred to a mineralizing mixer.

[0105] Hydroxyapatite powder (12% of the slag mass) is added to a mineralizing mixer and mixed at 80 rpm for 30 minutes. The mixture is then transferred to a curing tank and cured at room temperature for 48 hours. The cured mineralized slag is then mixed with a vitrified matrix (SiO2:Al2O3:CaO = 6:2:2, representing 36% of the total material) and fed into a vitrification furnace, where it is melted at 1500°C for 1 hour to form a vitreous body. The vitreous body is then quenched and crushed to a particle size of ≤3 mm, mixed with Portland cement (20% of the vitreous body mass), and pressed into a solidified body using a hydraulic press at 15 MPa.

[0106] Example 4

[0107] 100 kg of hazardous waste containing 28.3 g / kg of lead, 12.7 g / kg of copper, and 0.5 ng / g of dioxin (I-TEQ) was crushed to a particle size of ≤5 mm using a jaw crusher. The mixture was then transferred to a homogenization mixing tank and mechanically stirred at 150 rpm for 30 minutes, adjusting the moisture content to 45%. The mixture was then transferred to a bioreactor, where 2 kg of a composite microbial inoculant (SRB:MPB:BS) was added in a ratio of 60:30:10. The reaction temperature was maintained at 35°C, and the biosorption reaction was carried out for 16 hours. After completion of the reaction, a thiol-containing precipitant (0.8% of the hazardous waste mass) was added to the tank, stirring was continued for 1 hour, and the filter cake was obtained after solid-liquid separation using a plate and frame filter press.

[0108] The filter cake is placed in a plasma melting furnace, nitrogen is introduced to maintain a reducing atmosphere, and the furnace temperature is controlled at 1700°C for 2 hours to decompose organic pollutants and allow heavy metal oxides to enter the slag phase. The molten slag phase enters the microwave melting bath through a chute, where coke powder (5% of the slag mass) is added. The microwave melting bath temperature is controlled at 1320°C for 1.5 hours of reduction. The liquid metal phase is then recovered by sedimentation, and the remaining slag phase is transferred to a mineralizing mixer.

[0109] Hydroxyapatite powder (12% of the slag mass) is added to a mineralizing mixer and mixed at 80 rpm for 30 minutes. The mixture is then transferred to a curing tank and cured at room temperature for 48 hours. The cured mineralized slag is then mixed with a vitrified matrix (SiO2:Al2O3:CaO = 6:2:2, representing 44% of the total material) and fed into a vitrification furnace, where it is melted at 1500°C for 1 hour to form a vitreous body. The vitreous body is then quenched and crushed to a particle size of ≤3 mm, mixed with Portland cement (20% of the vitreous body mass), and pressed into a solidified body using a hydraulic press at 15 MPa.

[0110] Example 5

[0111] 100 kg of hazardous waste containing 28.3 g / kg of lead, 12.7 g / kg of copper, and 0.5 ng / g of dioxin (I-TEQ) was crushed to a particle size of ≤5 mm using a jaw crusher. The mixture was then transferred to a homogenization mixing tank and mechanically stirred at 150 rpm for 30 minutes, adjusting the moisture content to 45%. The mixture was then transferred to a bioreactor, where 2 kg of a composite microbial inoculant (SRB:MPB:BS) was added in a ratio of 60:30:10. The reaction temperature was maintained at 35°C, and the biosorption reaction was carried out for 20 hours. After completion of the reaction, a thiol-containing precipitant (0.8% of the hazardous waste mass) was added to the tank, stirring was continued for 1 hour, and solid-liquid separation was performed using a plate and frame filter press to obtain a filter cake.

[0112] The filter cake is placed in a plasma melting furnace, nitrogen is introduced to maintain a reducing atmosphere, and the furnace temperature is controlled at 1700°C for 2 hours to decompose organic pollutants and allow heavy metal oxides to enter the slag phase. The molten slag phase enters the microwave melting bath through a chute, where coke powder (5% of the slag mass) is added. The microwave melting bath temperature is controlled at 1250°C for 1.5 hours of reduction. The liquid metal phase is then recovered by sedimentation, and the remaining slag phase is transferred to a mineralizing mixer.

[0113] Hydroxyapatite powder (12% of the slag mass) is added to a mineralizing mixer and mixed at 80 rpm for 30 minutes. The mixture is then transferred to a curing tank and cured at room temperature for 48 hours. The cured mineralized slag is then mixed with a vitrified matrix (SiO2:Al2O3:CaO = 6:2:2, representing 40% of the total material) and fed into a vitrification furnace, where it is melted at 1500°C for 1 hour to form a vitreous body. The vitreous body is then quenched and crushed to a particle size of ≤3 mm, mixed with Portland cement (20% of the vitreous body mass), and pressed into a solidified body using a hydraulic press at 15 MPa.

[0114] Example 6

[0115] 100 kg of hazardous waste containing 28.3 g / kg of lead, 12.7 g / kg of copper, and 0.5 ng / g of dioxin (I-TEQ) was crushed to a particle size of ≤5 mm using a jaw crusher. The mixture was then transferred to a homogenization mixing tank and mechanically stirred at 150 rpm for 30 minutes, adjusting the moisture content to 45%. The mixture was then transferred to a bioreactor, where 2 kg of a composite microbial inoculant (SRB:MPB:BS) was added in a ratio of 60:30:10. The reaction temperature was maintained at 35°C, and the biosorption reaction was carried out for 8 hours. After completion of the reaction, a thiol-containing precipitant (0.8% of the hazardous waste mass) was added to the tank, stirring was continued for 1 hour, and the filter cake was obtained through solid-liquid separation using a plate and frame filter press.

[0116] The filter cake is placed in a plasma melting furnace, nitrogen is introduced to maintain a reducing atmosphere, and the furnace temperature is controlled at 1700°C for 2 hours to decompose organic pollutants and allow heavy metal oxides to enter the slag phase. The molten slag phase enters the microwave melting bath through a chute, where coke powder (5% of the slag mass) is added. The microwave melting bath temperature is controlled at 1100°C for 1.5 hours of reduction. The liquid metal phase is then recovered by sedimentation, and the remaining slag phase is transferred to a mineralizing mixer.

[0117] Hydroxyapatite powder (12% of the slag mass) is added to a mineralizing mixer and mixed at 80 rpm for 30 minutes. The mixture is then transferred to a curing tank and cured at room temperature for 48 hours. The cured mineralized slag is then mixed with a vitrified matrix (SiO2:Al2O3:CaO = 6:2:2, representing 32% of the total material) and fed into a vitrification furnace, where it is melted at 1500°C for 1 hour to form a vitreous body. The vitreous body is then quenched and crushed to a particle size of ≤3 mm, mixed with Portland cement (20% of the vitreous body mass), and pressed into a solidified body using a hydraulic press at 15 MPa.

[0118] Example 7

[0119] 100 kg of hazardous waste containing 28.3 g / kg of Pb, 12.7 g / kg of Cu, and 0.5 ng / g of dioxin (I-TEQ) was crushed to a particle size of ≤5 mm using a jaw crusher. The mixture was then transferred to a homogenization mixing tank and mechanically stirred at 150 rpm for 30 minutes, adjusting the moisture content to 45%. The mixture was then transferred to a bioreactor, where 2 kg of a composite microbial inoculant (SRB:MPB:BS) was added in a ratio of 60:30:10. The reaction temperature was maintained at 35°C, and the biosorption reaction was carried out for 28 hours. After completion of the reaction, a thiol-containing precipitant (0.8% of the hazardous waste mass) was added to the tank, stirring was continued for 1 hour, and the filter cake was obtained through solid-liquid separation using a plate and frame filter press.

[0120] The filter cake is placed in a plasma melting furnace, nitrogen is introduced to maintain a reducing atmosphere, and the furnace temperature is controlled at 1700°C for 2 hours to decompose organic pollutants and allow heavy metal oxides to enter the slag phase. The molten slag phase enters the microwave melting bath through a chute, where coke powder (5% of the slag mass) is added. The microwave melting bath temperature is controlled at 1400°C for 1.5 hours of reduction. The liquid metal phase is then recovered by sedimentation, and the remaining slag phase is transferred to a mineralizing mixer.

[0121] Hydroxyapatite powder (12% of the slag mass) is added to a mineralizing mixer and mixed at 80 rpm for 30 minutes. The mixture is then transferred to a curing tank and cured at room temperature for 48 hours. The cured mineralized slag is then mixed with a vitrified matrix (SiO2:Al2O3:CaO = 6:2:2, representing 48% of the total material) and fed into a vitrification furnace, where it is melted at 1500°C for 1 hour to form a vitreous body. The vitreous body is then quenched and crushed to a particle size of ≤3 mm, mixed with Portland cement (20% of the vitreous body mass), and pressed into a solidified body using a hydraulic press at 15 MPa.

[0122] Example 8

[0123] 100 kg of hazardous waste containing 28.3 g / kg of lead, 12.7 g / kg of copper, and 0.5 ng / g of dioxin (I-TEQ) was crushed to a particle size of ≤5 mm using a jaw crusher. The mixture was then transferred to a homogenization mixing tank and mechanically stirred at 150 rpm for 30 minutes, adjusting the moisture content to 45%. The mixture was then transferred to a bioreactor, where 2 kg of a composite microbial inoculant (SRB:MPB:BS) was added in a ratio of 60:30:10. The reaction temperature was maintained at 35°C, and the biosorption reaction was carried out for 5 hours. After completion of the reaction, a thiol-containing precipitant (0.8% of the hazardous waste mass) was added to the tank, stirring was continued for 1 hour, and solid-liquid separation was performed using a plate and frame filter press to obtain a filter cake.

[0124] The filter cake is placed in a plasma melting furnace, nitrogen is introduced to maintain a reducing atmosphere, and the furnace temperature is controlled at 1700°C for 2 hours to decompose organic pollutants and allow heavy metal oxides to enter the slag phase. The molten slag phase enters the microwave melting bath through a chute, where coke powder (5% of the slag mass) is added. The microwave melting bath temperature is controlled at 1050°C for 1.5 hours of reduction. The liquid metal phase is then recovered by sedimentation, and the remaining slag phase is transferred to a mineralizing mixer.

[0125] Hydroxyapatite powder (12% of the slag mass) is added to a mineralizing mixer and mixed at 80 rpm for 30 minutes. The mixture is then transferred to a curing tank and cured at room temperature for 48 hours. The cured mineralized slag is then mixed with a vitrified matrix (SiO2:Al2O3:CaO = 6:2:2, representing 30% of the total material) and fed into a vitrification furnace, where it is melted at 1500°C for 1 hour to form a vitreous body. The vitreous body is then quenched and crushed to a particle size of ≤3 mm, mixed with Portland cement (20% of the vitreous body mass), and pressed into a solidified body using a hydraulic press at 15 MPa.

[0126] Embodiment 9

[0127] 100 kg of hazardous waste containing 28.3 g / kg of Pb, 12.7 g / kg of Cu, and 0.5 ng / g of dioxin (I-TEQ) was crushed to a particle size of ≤5 mm using a jaw crusher. The mixture was then transferred to a homogenization mixing tank and mechanically stirred at 150 rpm for 30 minutes, adjusting the moisture content to 45%. The mixture was then transferred to a bioreactor, where 2 kg of a composite microbial inoculant (SRB:MPB:BS) was added in a ratio of 60:30:10. The reaction temperature was maintained at 35°C, and the biosorption reaction was carried out for 30 hours. After completion of the reaction, a thiol-containing precipitant (0.8% of the hazardous waste mass) was added to the tank, stirring was continued for 1 hour, and solid-liquid separation was performed using a plate and frame filter press to obtain a filter cake.

[0128] The filter cake is placed in a plasma melting furnace, nitrogen is introduced to maintain a reducing atmosphere, and the furnace temperature is controlled at 1700°C for 2 hours to decompose organic pollutants and allow heavy metal oxides to enter the slag phase. The molten slag phase enters the microwave melting bath through a chute, where coke powder (5% of the slag mass) is added. The microwave melting bath temperature is controlled at 1450°C for 1.5 hours of reduction. The liquid metal phase is then recovered by sedimentation, and the remaining slag phase is transferred to a mineralizing mixer.

[0129] Hydroxyapatite powder (12% of the slag mass) is added to a mineralizing mixer and mixed at 80 rpm for 30 minutes. The mixture is then transferred to a curing tank and cured at room temperature for 48 hours. The cured mineralized slag is then mixed with a vitrified matrix (SiO2:Al2O3:CaO = 6:2:2, representing 50% of the total material) and fed into a vitrification furnace, where it is melted at 1500°C for 1 hour to form a vitreous body. The vitreous body is then quenched and crushed to a particle size of ≤3 mm, mixed with Portland cement (20% of the vitreous body mass), and pressed into a solidified body using a hydraulic press at 15 MPa.

[0130] Example 10 (blank control group)

[0131] 100 kg of hazardous waste containing 28.3 g / kg of Pb, 12.7 g / kg of Cu, and 0.5 ng / g of dioxin (I-TEQ) was crushed to a particle size of ≤5 mm using a jaw crusher. The mixture was then transferred to a homogenization mixing tank and mechanically stirred at 150 rpm for 30 minutes to adjust the moisture content to 45%. A thiol-containing precipitant (0.8% of the hazardous waste mass) was added directly to the mixing tank. After stirring for 1 hour, the mixture was subjected to solid-liquid separation using a plate and frame filter press to obtain a filter cake (omitting the biosorption step).

[0132] The filter cake was placed in a plasma melting furnace, nitrogen was introduced to maintain a reducing atmosphere, and the furnace temperature was controlled at 1700°C for 2 hours (omitting the microwave bath reduction step), decomposing organic contaminants and incorporating heavy metal oxides into the slag phase. The molten slag phase was transferred directly to a mineralizing mixer via a chute, where hydroxyapatite powder (12% of the slag mass) was added. After mixing at 80 rpm for 30 minutes, the slag phase was transferred to a curing tank for 48 hours at room temperature. The cured mineralized slag phase was mixed with a vitrified matrix (SiO2:Al2O3:CaO = 6:2:2, representing 38% of the total material) and then transferred to a vitrification melting furnace, where it was melted at 1500°C for 1 hour to form a vitreous body. The vitreous body was then quenched by water, crushed to a particle size of ≤3 mm, mixed with Portland cement (20% of the vitreous body mass), and pressed into a solidified body using a hydraulic press at 15 MPa.

[0133] Specific working process

[0134] Heavy metal-containing sludge / residue and organic hazardous waste containing polychlorinated biphenyls and dioxins are crushed in jaw or hammer crushers before entering a homogenization mixing tank. Mechanical agitation is used to mix the mixture evenly, and after adjusting the moisture content, the mixture is transferred to a bioreactor. A composite microbial inoculant is added for adsorption, decomposing the organic matter and initially fixing the heavy metals. The finished product enters a chemical precipitation tank, where a thiol-containing precipitant is added for reaction. After solid-liquid separation, the filter cake is obtained using a plate and frame filter press, and the filtrate enters the sewage treatment system.

[0135] The filter cake is directly conveyed to the plasma melting furnace, where it is melted by high-temperature plasma in a reducing atmosphere. Organic pollutants are decomposed into harmless gases, and heavy metal oxides enter the slag phase. The high-temperature slag phase enters the microwave melting bath through a chute. After the addition of coke powder, it undergoes microwave-assisted reduction. The liquid metal phase is recovered by sedimentation, and the remaining slag phase is transferred to a mineralizing mixer.

[0136] Hydroxyapatite powder is added to the mineralizing mixer and mixed with the slag. The mixture is then transferred to a curing tank for room temperature curing, where heavy metal ions react with the hydroxyapatite to form stable crystals. The mineralized slag is mixed with a vitrified substrate and then melted into a vitrification furnace to form a vitreous body. This is then quenched, quenched, and mixed with cement. The product is then pressed into shape using a hydraulic press, ultimately yielding a solidified body that can be safely landfilled or recycled.

[0137] The various technical features described in the above exemplary embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above exemplary embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A harmless treatment process for non-ferrous metal hazardous waste, characterized in that: The following steps are involved: S1: (a) Crush the hazardous waste to a particle size of ≤5 mm, homogenize and adjust the moisture content to 40%-60%; (b) using a composite microbial agent for biosorption, wherein the composite agent is composed of sulfate-reducing bacteria (55%-65%), methanogens (25%-35%), and Bacillus subtilis (5%-15%), and the agent dosage is 0.4%-0.6% of the mass of the hazardous waste; (c) After biosorption, chemical precipitation is performed using sodium diethyldithiocarbamate (DDTC) containing a thiol functional group at a stoichiometric ratio of 1.1 to 1.3 times the residual concentration of the heavy metal, and solid-liquid separation is performed to obtain a filter cake having a moisture content of ≤60%; S2: (a) Decomposing the organic pollutants in the pretreated filter cake by plasma melting, the plasma temperature is 1600-1800°C, the reaction atmosphere is a reducing atmosphere (O2 concentration ≤ 5%), and the hazardous waste residence time is 3-5s; (b) The high-temperature slag phase (temperature ≥ 1000°C) produced by plasma melting is directly introduced into a microwave molten pool, where heavy metals are reduced by microwaves at a frequency of 2.45 GHz. The molten pool temperature is 1150-1350°C, and the reducing agent dosage is 2%-6% of the slag phase mass. S3: (a) hydroxyapatite mineralization of the slag phase produced by the microwave melting pool, with the hydroxyapatite addition amount being 8%-17% of the slag phase mass, the moisture content after mixing being 18%-27%, and curing at room temperature for 5-9 days; (b) The mineralized slag phase is mixed with a vitrified matrix (SiO2:Al2O3:CaO=5.5-6.5:1.5-2.5:1.5-2.5, with the addition amount being 35%-45% of the mass of the mineralized slag phase), melted at 1350-1550°C, and then quenched in water (cooling rate ≥80°C / s), mixed with 4%-6% cement, and pressed into shape (pressure 8-12 MPa).

2. The harmless treatment process for non-ferrous metal hazardous waste according to claim 1, characterized in that: The reaction conditions of the biosorption are: temperature 33-37° C., pH=6.3-7.7, stirring rate 70-110 rpm, and reaction time 10-26 h.

3. The harmless treatment process for non-ferrous metal hazardous waste according to claim 1, characterized in that: The reaction conditions of the chemical precipitation are: pH = 7.8-9.2, stirring rate 130-170 rpm, reaction time 25-35 min; solid-liquid separation uses a plate and frame filter press (pressure 0.7-0.9 MPa), and the heavy metal concentration of the filtrate is ≤0.5 mg / L.

4. The harmless treatment process for non-ferrous metal hazardous waste according to claim 1, characterized in that: The plasma-melted gaseous product is treated by a quenching tower (1600-1800° C. to 180-220° C., residence time <2.5s) + activated carbon adsorption + bag dust removal.

5. The harmless treatment process for non-ferrous metal hazardous waste according to claim 1, characterized in that: The reaction time of the microwave melting pool is 13-22 minutes.

6. The harmless treatment process for non-ferrous metal hazardous waste according to claim 1, characterized in that: The crystals generated by the mineralization of hydroxyapatite include pyromorphite or hydroxyapatite.

7. The harmless treatment process for non-ferrous metal hazardous waste according to claim 1, characterized in that: The holding time of the vitrification melting is 0.8-1.2h.

8. The harmless treatment process for non-ferrous metal hazardous waste according to claim 1, characterized in that: The reducing agent is coke powder with a particle size of ≤2mm.

9. The harmless treatment process for non-ferrous metal hazardous waste according to claim 1, characterized in that: The particle size of the solidified body after water quenching and rapid cooling is ≤50mm.

10. The harmless treatment process for non-ferrous metal hazardous waste according to claim 1, characterized in that: The non-ferrous metal hazardous waste includes sludge residue containing heavy metals (Pb, Cu, Ni) and organic hazardous waste containing polychlorinated biphenyls and dioxins.

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