Methods for handling hazardous solid waste

Abstract

The present invention provides a method for treating hazardous waste solids, which belongs to a chemical treatment method involving organic materials. The hazardous waste solids are pre-treated and added to thionyl chloride, stirred evenly, to obtain a material slurry; trifluoromethylthianthrene trifluoromethanesulfonate is dissolved and added to the material slurry, stirred and leached for a predetermined time at normal temperature and pressure to obtain a metal-containing purified liquid and treated tailings; the concentration of each metal in the metal-containing purified liquid is detected by ICP-OES, and the dissolution-purification-recovery effect of each metal is calculated. The present invention uses trifluoromethylthianthrene trifluoromethanesulfonate to treat hazardous waste solids, and through the synergistic effect between functionalized functional groups, while managing hazardous wastes, the recycling of resources is achieved; the sulfur in the trifluoromethylthianthrene trifluoromethanesulfonate is used as a chelating site, which can be chelated with many heavy metals to achieve a comprehensive management effect of hazardous waste solids.

Description

Technical Field

[0001] The present invention relates to the technical field of hazardous solid waste resource utilization, and in particular to a method for treating hazardous solid waste. Background Art

[0002] Electronic waste is listed as a hazardous solid waste. The most valuable part of electronic waste is concentrated in printed circuit boards (PCBs). Printed circuit boards (PCBs) are components of almost all electrical and electronic equipment (EEE). Printed circuit boards (PCBs) generally account for 4-7% of the total mass of electrical and electronic equipment (EEE), and the proportion of printed circuit boards in electronic products such as electronic communications products, computers, and televisions is even greater. With the rapid advancement of technology and the rapid penetration of the market, a large amount of waste electrical and electronic equipment (WEEE) has been generated worldwide. Especially driven by small electronic products, its amount continues to grow at an alarming rate. In 2016, the global annual production of WEEE reached 44.7 million tons / year, and it is expected to reach 52.2 million tons / year by 2025. However, many developing countries currently lack advanced processing means and research methods for the recycling of electronic waste. Recycling work is usually carried out in labor-intensive workshops, and simple landfill or incineration treatment causes great harm to humans, animals and the environment.

[0003] The pyrometallurgical resource recovery technology for hazardous solid waste refers to the process of removing plastics and other organic components from discarded electrical and electronic products and their dismantling products through pyrometallurgical treatment methods such as incineration, pyrolysis, and smelting, so that various metals are melted to form alloys, and then the separation of precious and base metals, precious metals and non-ferrous metals is achieved through electrolysis, anode mud treatment and refining. With traditional pyrometallurgical treatment technology, the comprehensive recovery rate of metal resources can generally reach more than 95%. After pyrometallurgical treatment of electronic waste, precious metals and base metals are effectively separated, but it is usually difficult to obtain high-purity metals, so it is often necessary to combine wet processes for purification. Due to the differences in the composition of electronic waste and natural resources, the use of traditional pyrometallurgical technology for treating natural mineral resources to treat electronic waste can easily form toxic gases such as dioxins during the incineration and smelting process, causing pollution to the atmospheric environment. At the same time, the cost of tail gas treatment is high, and thus the limitations are strong, making it difficult to meet current environmental protection standards.

[0004] At present, there are many environmentally friendly methods for treating electronic waste, including the aqua regia method, the halogen method, the glycine method, etc. While achieving the recovery of precious metals, there are still certain limitations. The most obvious problem is that the unique processing structure of electronic waste causes some metal resources to be in the interlayer of the circuit board substrate material. The traditional wet process for treating electronic waste has a certain leaching limit, and the agent cannot penetrate into the interlayer, resulting in some metals, especially heavy metals, remaining in the material, making it impossible to maximize the recycling of resources and meet the environmental protection requirements of the treated materials.

[0005] Trifluoromethylthianthrene trifluoromethanesulfonate contains trifluoromethyl group and trifluoromethanesulfonic acid group, which can give the compound certain physical and chemical properties and are widely used in organic synthetic chemistry. The application of trifluoromethylthianthrene trifluoromethanesulfonate in the field of hazardous waste treatment is a new use based on existing compounds. This new application field has important practical applications and market prospects, and will bring new solutions and technological innovations to the field of waste treatment.

[0006] In view of this, it is necessary to design an improved method for treating hazardous waste solids to solve the above problems. Summary of the invention

[0007] In view of the defects of the above-mentioned prior art, the purpose of the present invention is to provide a method for treating hazardous waste solids, utilizing the synergistic effect of functionalized functional groups in the molecular structure of each agent to achieve the recycling of valuable metals in hazardous waste solids and the purification and recovery of harmful metals, so as to solve the resource management of hazardous waste solids and achieve both economic and environmental benefits.

[0008] To achieve the above object, the present invention provides a method for treating hazardous solid waste, comprising the following steps:

[0009] S1. The hazardous waste solid is pretreated and added to thionyl chloride, stirred evenly to obtain a material slurry;

[0010] S2. After dissolving the trifluoromethylthianthrene trifluoromethanesulfonate, add the solution to the material slurry obtained in step S1, stir and leach for a predetermined time at room temperature and pressure to obtain a metal-containing purified liquid and treated tailings;

[0011] S3. Use ICP-OES (inductively coupled plasma emission spectrometer) to detect the concentration of each metal in the metal-containing purification solution and calculate the dissolution-purification-recovery effect of each metal.

[0012] As a further improvement of the present invention, the hazardous waste solid includes one or more of waste circuit boards, waste photovoltaic modules, and waste battery electrode modules.

[0013] As a further improvement of the present invention, in step S1, the hazardous solid waste is pre-treated by splitting, shearing and crushing the hazardous solid waste to a predetermined concentration, wherein the predetermined concentration is that the material with a particle size of -0.355 mm accounts for 75% to 85% of the total mass of the material.

[0014] As a further improvement of the present invention, the mass concentration percentage of the hazardous waste solid to the thionyl chloride is 10% to 30%.

[0015] As a further improvement of the present invention, in step S2, the trifluoromethylthianthrene trifluoromethanesulfonate is one or more of TT-1, TT-2 and TT-3. The TT-1 is 5-(trifluoromethyl)-5H-dithioanthracene-5-ium trifluoromethanesulfonate, the TT-2 is S-(trifluoromethyl)dibenzothiophene trifluoromethanesulfonate, and the TT-3 is diphenyl(trifluoromethyl)sulfonium trifluoromethanesulfonate.

[0016] As a further improvement of the present invention, the molar concentration of the trifluoromethylthianthrene trifluoromethanesulfonate in the material slurry is 0.01-1 mol / L.

[0017] As a further improvement of the present invention, the solvent used to dissolve the trifluoromethylthianthrene trifluoromethanesulfonate is thionyl chloride.

[0018] As a further improvement of the present invention, in step S2, the stirring leaching time is 2 to 3 hours. The beneficial effects of the present invention are:

[0019] 1. The present invention provides a method for treating hazardous waste solids, wherein the hazardous waste solids are pre-treated and added to thionyl chloride, and stirred evenly to obtain a material slurry; after dissolving a trifluoromethylthianthrene trifluoromethanesulfonate, the trifluoromethylthianthrene trifluoromethanesulfonate is added to the material slurry, and stirred and leached for a predetermined time at room temperature and pressure to obtain a metal-containing purified liquid and treated tailings; the concentration of each metal in the metal-containing purified liquid is detected by ICP-OES, and the dissolution-purification-recovery effect of each metal is calculated. The present invention uses a trifluoromethylthianthrene trifluoromethanesulfonate as a reagent for treating hazardous waste solids, and through the synergistic effect between functionalized functional groups, while treating hazardous wastes, the recycling of resources is achieved.

[0020] 2. In the process of treating hazardous waste solids, the present invention uses thionyl chloride as a solution to dissolve organic components in hazardous waste solids, such as flame retardant coatings, etc., under the premise of dissolving agents. At the same time, some organic polymer materials swell during the dissolution process, and the metal in the interlayer is fully exposed, which provides necessary conditions for subsequent agent contact-dissolution. The trifluoromethyl in the trifluoromethylthianthrene trifluoromethanesulfonate is easily converted into a trifluoromethyl free radical, which has extremely high reactivity and undergoes free radical substitution with thionyl chloride, and is converted into a chlorine free radical. The chlorine free radical can react with metals with inactive chemical properties in the material to achieve the dissolution-recovery of precious metals, such as gold, palladium, platinum, etc., which is different from the previous recovery technology of precious metals, which requires the introduction of an oxidant to achieve the conversion of the target metal valence state. In addition, in the free radical conversion process, the sulfur in the trifluoromethylthianthrene trifluoromethanesulfonate can be used as a chelating site to achieve chelation with many heavy metals (mercury, manganese, cadmium), thereby achieving a comprehensive treatment effect of hazardous waste solids. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The scanning electron microscope and energy spectrum analysis test diagram of the metal-containing purified liquid after recovery treatment in Example 1 of the present invention. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the scheme of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0024] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0025] The present invention provides a method for treating hazardous waste solids, comprising the following steps:

[0026] S1. Pre-treat hazardous waste solids and add them to thionyl chloride, stir evenly, and obtain material slurry.

[0027] Specifically, the hazardous waste solids include one or more of waste circuit boards, waste photovoltaic modules, and waste battery electrode modules. The hazardous waste solids are split, sheared, and crushed to a particle size of -0.355 mm, which accounts for 75% to 85% of the total mass of the materials, and added to thionyl chloride. The mass concentration percentage of the hazardous waste solids and thionyl chloride is preferably 10% to 30%.

[0028] S2. After the trifluoromethylthianthrene trifluoromethanesulfonate is dissolved, it is added to the material slurry obtained in step S1, and stirred and leached for a predetermined time at normal temperature and pressure to obtain a metal-containing purified liquid and treated tailings.

[0029] Specifically, a trifluoromethylthianthrene trifluoromethanesulfonate is dissolved in an appropriate amount of thionyl chloride, added to a material slurry and leached for 2 to 3 hours, wherein the trifluoromethylthianthrene trifluoromethanesulfonate is one or more of TT-1, TT-2 and TT-3, wherein TT-1 is 5-(trifluoromethyl)-5H-dithioanthene-5-ium trifluoromethanesulfonate, TT-2 is S-(trifluoromethyl)dibenzothiophene trifluoromethanesulfonate, and TT-3 is diphenyl (trifluoromethyl) sulfonium trifluoromethanesulfonate; and the molar concentration of the trifluoromethylthianthrene trifluoromethanesulfonate in the material slurry is 0.01 to 1 mol / L.

[0030] S3. Use ICP-OES to detect the concentration of each metal in the metal-containing purification solution and calculate the dissolution-purification-recovery effect of each metal.

[0031] The method for treating hazardous solid waste provided by the present invention is described below with reference to specific embodiments.

[0032] Example 1

[0033] Example 1 provides a method for treating hazardous solid waste. The hazardous solid waste material used in the experiment is waste circuit boards, and the content of each element is shown in Table 1:

[0034] Table 1 Element analysis of waste circuit boards after preliminary treatment

[0035] Element Au* Pd* Pt* Cd Fe Cu Hg Mn content(%) 46.23 0.13 0.20 1.41 12.38 0.15 0.50 0.79

[0036] Note: *Unit is g / t;

[0037] The specific steps include:

[0038] S1. Split, shear and crush the waste circuit boards until the material size is -0.355mm, accounting for 85% of the total mass of the material, add thionyl chloride, and the mass concentration percentage of the material and thionyl chloride is 30%;

[0039] S2. Add the dissolved TT-1 to the material slurry prepared in step S1, the molar concentration of which is 0.05 mol / L of thionyl chloride, and stir and leach for 2 h at room temperature and pressure to obtain a metal-containing purified liquid and treated tailings;

[0040] S3. Use ICP-OES to detect the concentration of each metal in the metal-containing purification solution, and calculate the dissolution-purification-recovery effect of each metal, as shown in Table 2, wherein the detection error of ICP-OES is ±2%.

[0041] The metal-containing purified liquid obtained above was adjusted to neutral (pH=7±0.2), and allowed to stand for 10 minutes to generate a precipitate. The precipitate was tested by scanning electron microscopy and energy spectrum analysis. Figure 1 As shown, the precipitate components are mainly Mn and Fe, while gold, platinum, palladium, copper and mercury exist in the purified liquid without generating precipitate.

[0042] Example 2-3

[0043] Examples 2-3 respectively provide a method for treating hazardous waste solids. Compared with Example 1, the only difference is that the types of trifluoromethylthianthrene trifluoromethanesulfonate are different, namely TT-2 and TT-3. Other experimental parameters and conditions are basically the same as those in Example 1 and will not be repeated here.

[0044] Embodiment 4-5

[0045] Examples 4-5 respectively provide a method for treating hazardous waste solids. Compared with Example 1, the only difference is that the types of hazardous waste solids are different, namely, waste photovoltaic components and waste battery electrode components. Other experimental parameters and conditions are basically the same as those in Example 1 and will not be repeated here.

[0046] Comparative Example 1

[0047] Comparative Example 1 provides a method for treating hazardous waste solids. Compared with Example 1, the only difference is that the agent is triphenylsulfonium trifluoromethanesulfonate, and other experimental parameters and conditions are basically the same as those in Example 1, which will not be repeated here.

[0048] The dissolution-purification-recovery effects of each metal in Examples 1 to 5 and Comparative Example 1 are shown in the following table.

[0049] Table 2 Dissolution-purification-recovery effect of each metal

[0050]

[0051]

[0052] As shown in Table 2, in Examples 1 to 5, through the synergistic effect between the functional groups of the reagents, while treating hazardous wastes, the recycling of resources is achieved. In addition to having good dissolution-purification-recovery effects on precious metals such as gold, palladium, platinum and heavy metals such as mercury, manganese and cadmium, the present invention also has excellent treatment effects on iron and copper. In Comparative Example 1, due to the lack of free radicals to initiate fragment trifluoromethyl free radicals, free radical transfer cannot be performed to generate chlorine free radicals, and ultimately the precious metals (Au, Pd, Pt) and Cd cannot be dissolved.

[0053] In summary, the present invention provides a medicament and process for treating hazardous waste solids. In the process of treating hazardous waste solids, the medicament of the present invention uses thionyl chloride as a solution to dissolve the organic components in the hazardous waste solids, such as flame retardant coatings, etc., under the premise of dissolving the medicament. At the same time, part of the organic polymer material swells during the dissolution process, and the metal in the interlayer is fully exposed, which provides the necessary conditions for the subsequent contact-dissolution of the medicament. The trifluoromethyl in the trifluoromethylthianthrene trifluoromethanesulfonate is easily converted into a trifluoromethyl free radical, which has a very high reactivity and undergoes free radical substitution with thionyl chloride to be converted into a chlorine free radical. The chlorine free radical can react with the metal in the material that is chemically inactive to achieve the dissolution-recovery of precious metals, such as gold, palladium, platinum, etc. This is different from the previous precious metal recovery technology, which requires the introduction of an oxidant to achieve the transformation of the target metal valence state. In addition, in the free radical conversion process, the sulfur (S:) in the trifluoromethylthianthrene trifluoromethanesulfonate is used as a chelating site to achieve chelation with many heavy metals (mercury, manganese, cadmium), achieving a comprehensive treatment effect of hazardous waste solids.

[0054] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for treating hazardous solid waste, characterized in that: The following steps are involved: S1. Adding the pretreated hazardous waste solid to thionyl chloride and stirring evenly to obtain a material slurry; the hazardous waste solid includes one or more of waste circuit boards, waste photovoltaic modules, and waste battery electrode modules; S2. After dissolving the trifluoromethylthianthrene trifluoromethanesulfonate, add the solution to the material slurry obtained in step S1, stir and leach for a predetermined time at room temperature and pressure to obtain a metal-containing purified liquid and treated tailings; S3. Use ICP-OES to detect the concentration of each metal in the metal-containing purification solution and calculate the dissolution-purification-recovery effect of each metal.

2. The method for treating hazardous solid waste according to claim 1, characterized in that: In step S1, the hazardous solid waste is pretreated by splitting, shearing and crushing the hazardous solid waste to a predetermined concentration.

3. The method for treating hazardous solid waste according to claim 2, characterized in that: The predetermined concentration is that the material with a particle size of -0.355 mm accounts for 75% to 85% of the total mass of the material.

4. The method for treating hazardous solid waste according to claim 3, characterized in that: The mass concentration percentage of the hazardous waste solid and the thionyl chloride is 10% to 30%.

5. The method for treating hazardous solid waste according to claim 1, characterized in that: In step S2, the trifluoromethylthianthrene trifluoromethanesulfonate is one or more of TT-1, TT-2 and TT-3, wherein TT-1 is 5-(trifluoromethyl)-5H-dithioanthene-5-ium trifluoromethanesulfonate, TT-2 is S-(trifluoromethyl)dibenzothiophene trifluoromethanesulfonate, and TT-3 is diphenyl(trifluoromethyl)sulfonium trifluoromethanesulfonate.

6. The method for treating hazardous solid waste according to claim 5, characterized in that: The molar concentration of the trifluoromethylthianthrene trifluoromethanesulfonate in the material slurry is 0.01-1 mol / L.

7. The method for treating hazardous solid waste according to claim 5, characterized in that: The solvent used to dissolve the trifluoromethylthianthrene trifluoromethanesulfonate is thionyl chloride.

8. The method for treating hazardous solid waste according to claim 1, characterized in that: In step S2, the stirring leaching time is 2 to 3 hours.

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