阅读说明：本技术 一种基于机械化学法协同工业固废处理pvc的方法 (Method for treating PVC (polyvinyl chloride) based on cooperation of mechanochemical method and industrial solid waste ) 是由 刘红盼 朱江 杨和山 段亨攀 李忠彬 倪海涛 于 2021-08-12 设计创作，主要内容包括：本发明公开了一种基于机械化学法协同工业固废处理PVC的方法,包括以下步骤：S1、将PVC颗粒进行初步破碎,破碎粒径为0.1～0.1cm；S2、常温常压下,将破碎后的PVC颗粒与工业固废放入球磨机中进行高能混合球磨。本发明所述机械化学法主要为固相反应,不涉及液态有机溶剂等,且最终产物无害化,不产生有害气体或液体；本发明所涉及的工艺简单,反应条件温和,大大降低了处理能耗和运行成本；本发明采用工业固废(高钙渣、高硅渣或高铝废渣等)对PVC降解过程中的氯元素进行原位捕集,实现了“以废治废”的目的。(The invention discloses a method for treating PVC (polyvinyl chloride) based on a mechanochemical method and industrial solid waste, which comprises the following steps of: s1, primarily crushing PVC particles, wherein the crushed particle size is 0.1-0.1 cm; and S2, placing the crushed PVC particles and the industrial solid wastes into a ball mill for high-energy mixing ball milling at normal temperature and normal pressure. The mechanochemical method is mainly a solid-phase reaction, does not relate to liquid organic solvents and the like, and the final product is harmless and does not generate harmful gas or liquid; the invention has simple process and mild reaction condition, and greatly reduces the treatment energy consumption and the operation cost; the invention adopts industrial solid waste (high-calcium slag, high-silicon slag or high-aluminum waste slag and the like) to carry out in-situ capture on chlorine element in the PVC degradation process, thereby realizing the purpose of treating waste by waste.)

1. A method for treating PVC based on a mechanochemical method and industrial solid waste is characterized by comprising the following steps:

s1, primarily crushing PVC particles, wherein the crushed particle size is 0.1-1 cm;

and S2, placing the crushed PVC particles and the industrial solid wastes into a ball mill for high-energy mixing ball milling at normal temperature and normal pressure.

2. The method for treating PVC based on the mechanochemical process and the industrial solid waste is characterized in that: the industrial solid waste is one or more of high-calcium slag, high-silicon slag or high-aluminum waste slag.

3. The method for treating PVC based on the mechanochemical process and the industrial solid waste is characterized in that: the mass ratio of the PVC to the industrial solid waste is 10-50: 1.

4. The method for treating PVC based on the mechanochemical process and the industrial solid waste is characterized in that: the ball milling tank and the ball body are made of stainless steel, and the rotating speed of the ball milling tank and the ball body is 20-250 revolutions per minute (large disc) and 50-550 revolutions per minute (ball milling tank).

5. The method for treating PVC based on the mechanochemical process and the industrial solid waste is characterized in that: the ball milling time is 30-180 min.

6. The method for treating PVC based on the mechanochemical process and the industrial solid waste is characterized in that: the industrial solid waste is one or more of red mud, carbide slag and steel slag.

Technical Field

The invention relates to the technical field of environmental pollution treatment, in particular to a method for treating PVC (polyvinyl chloride) based on a mechanochemical method in cooperation with industrial solid waste.

Background

Polyvinyl chloride (PVC) has low cost, wide material source, and physical and mechanical propertiesHas excellent performance and is widely applied to various fields of social production and life. Waste PVC is difficult to degrade in natural environment, and is mostly reduced and harmlessly treated by a heat treatment technology, but hydrogen chloride, dioxin substances and the like are generated by the combustion of PVC, so that the environment is seriously polluted. At present, the PVC degradation mechanism mainly comprises a free radical mechanism, an ion mechanism, a single molecule mechanism and the like, a heat treatment method is usually adopted to treat PVC, but the molecular structure of the PVC has 56-58% of chlorine content, and the generated chlorine free radical has strong corrosivity to the liner in a boiler. The PVC can be dechlorinated to eliminate the subsequent boiler corrosion hazard. The invention patent CN102824719A discloses a mechanochemical-based method for treating perfluoro-and polyfluoro-compound solid waste. The method comprises the steps of mixing perfluoro or polyfluoro compound solid waste with a defluorination reagent KOH under the conditions of normal temperature and normal pressure, and then placing the mixture in a dry planetary high-energy ball-milling reactor for reaction, wherein the mass ratio of the defluorination reagent to the perfluoro or polyfluoro compound is 5-95: 1, and the degradation and defluorination of the perfluoro or polyfluoro compound are realized by utilizing mechanochemical reaction. The invention patent CN103386314A discloses a method for preparing a photocatalyst with visible light response by mechanochemical treatment of polybrominated diphenyl ether solid waste, which comprises the steps of firstly, mixing polybrominated diphenyl ether solid waste with a debromination reagent (Bi)₂O₃) Mixing and placing the mixture in a ball milling tank of a ball mill, wherein the molar ratio of Bi to Br is 1 to 1, then adjusting the rotation speed of the ball mill to be 300-800 rpm and the running time to be about 15min to realize the rapid degradation and debromination of polybrominated diphenyl ether, and finally preparing the bromine-containing photocatalyst with visible light response through mechanochemical reaction.

At present, the disclosed mechanochemical dehalogenation reaction process mostly adopts pure chemical reagents for treatment. The invention fully utilizes the inorganic mineral phase in the industrial solid waste, activates or accelerates the reaction activity of the mineral phase and organic chloride through the ecological-friendly mechanochemical effect, and utilizes the inorganic components in the industrial solid waste to retard the generation of the chlorine-containing precursor in situ so as to achieve the aim of treating the waste by the waste.

Disclosure of Invention

The invention aims to provide a method for treating PVC based on a mechanochemical method and industrial solid waste, which aims to solve the problems in the prior art.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for treating PVC based on a mechanochemical method cooperated with industrial solid waste comprises the following steps:

s1, primarily crushing PVC particles, wherein the crushed particle size is 0.1-1 cm;

and S2, placing the crushed PVC particles and the industrial solid wastes into a ball mill for high-energy mixing ball milling at normal temperature and normal pressure.

Further, the industrial solid waste is one or more of high-calcium slag, high-silicon slag or high-aluminum waste slag

Further, the mass ratio of the PVC to the industrial solid waste is 10-50: 1.

Furthermore, the ball milling tank and the ball body are made of stainless steel, and the rotating speed is 20-250 revolutions per minute (large disc) and 50-550 revolutions per minute (ball milling tank).

Further, the ball milling time is 30-180 min.

Further, the industrial solid waste is one or more of red mud, carbide slag and steel slag.

Mechanochemistry is a method of applying mechanical energy to a solid, liquid or other condensed substance by means of shearing, rubbing, impact, extrusion, etc., to induce a change in the structure and physicochemical properties thereof, and to induce a chemical reaction. Unlike ordinary thermochemical reaction, the mechanochemical reaction is powered by mechanical energy rather than thermal energy, so that the reaction can be completed without harsh conditions such as high temperature, high pressure and the like.

The mechanochemical treatment process is to enhance the reaction activity of inert halogen atoms (Cl) in PVC molecules by a mechanical strengthening means, so that the inert halogen atoms and an alkaline dehalogenation reagent are subjected to chemical reaction and are converted into water-soluble metal halides; PVC or chlorine-containing waste, a dehalogenation reagent and a ball-milling medium steel ball are mixed and put into a ball mill for ball milling, and in the ball milling process, the steel ball continuously collides with waste particles, and mechanical energy is transmitted to PVC and dechlorination reagent (alkaline compound) particles, so that the PVC and the dechlorination reagent are continuously thinned, the reaction activity is enhanced, the PVC dehalogenation reaction is enhanced, and the harmlessness is realized.

Compared with the prior art, the invention has at least one of the following beneficial effects:

(1) the mechanochemical method is mainly a solid-phase reaction, does not relate to liquid organic solvents and the like, and the final product is harmless and does not generate harmful gas or liquid;

(2) the invention has simple process and mild reaction condition, and greatly reduces the treatment energy consumption and the operation cost;

(3) the invention adopts industrial solid waste (high-calcium slag, high-silicon slag or high-aluminum waste slag and the like) to carry out in-situ capture on chlorine element in the PVC degradation process, thereby realizing the purpose of treating waste by waste.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the following embodiments further describe the present invention in detail. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1:

a method for treating PVC based on a mechanochemical method cooperated with industrial solid waste comprises the following steps:

s1, primarily crushing PVC particles, wherein the crushed particle size is 0.1-1 cm;

and S2, placing the crushed PVC particles and the industrial solid wastes into a ball mill for high-energy mixing ball milling at normal temperature and normal pressure.

Example 2:

on the basis of example 1: the industrial solid waste is one or more of high-calcium slag, high-silicon slag or high-aluminum waste slag.

Example 3:

on the basis of examples 1-2: the mass ratio of the PVC to the industrial solid waste is 10-50: 1.

Example 4:

on the basis of examples 1 to 3: the ball milling tank and the ball body are made of stainless steel, and the rotating speed of the ball milling tank and the ball body is 20-250 revolutions per minute (large disc) and 50-550 revolutions per minute (ball milling tank).

Example 5:

on the basis of examples 1 to 4: the ball milling time is 30-180 min.

Example 6:

on the basis of examples 1 to 5: the industrial solid waste is one or more of red mud, carbide slag and steel slag.

Example 7:

the method for treating PVC based on the cooperation of the mechanochemical method and the industrial solid waste specifically comprises the following steps:

at room temperature, mixing the primarily crushed PVC particles with industrial solid waste red mud, putting the mixture into a stainless steel ball-milling tank for sealing, putting the loaded ball-milling tank into a ball mill, wherein the mass ratio of the red mud to the PVC is 20:1, setting the revolution (large disc) to be 100-150 r/m, the rotation (ball-milling tank) to be 50-60 r/m, and the time is 60 min.

Detecting chloride ions by a molar method through AgNO₃The standard solution titrates the solution containing the chloride ions, and the dechlorination rate of the PVC under the mechanochemical effect is calculated according to the consumption of the silver nitrate, and the result shows that the dechlorination rate is 62%.

Example 8:

the method for treating PVC based on the cooperation of the mechanochemical method and the industrial solid waste specifically comprises the following steps:

mixing the PVC particles after primary crushing and industrial solid waste carbide slag at room temperature, then placing the mixture into a ball milling tank made of stainless steel for sealing, then placing the ball milling tank after loading into a ball mill, wherein the mass ratio of the carbide slag to the PVC is 30:1, setting the revolution (large disc) to 220-250 revolutions per minute and the rotation (ball milling tank) to 500-550 revolutions per minute, and the time is 120 min.

Detecting chloride ions by a molar method through AgNO₃The standard solution titrates the solution containing the chloride ions, and the dechlorination rate of the PVC under the mechanochemical effect is calculated according to the consumption of the silver nitrate, and the result shows that the dechlorination rate is 95%.

Example 9:

the method for treating PVC based on the cooperation of the mechanochemical method and the industrial solid waste specifically comprises the following steps:

mixing the PVC particles after primary crushing and industrial solid waste steel slag at room temperature, then putting the mixture into a ball milling tank made of stainless steel for sealing, then putting the ball milling tank after charging into a ball mill, setting the mass ratio of carbide slag to PVC to be 40:1, setting the revolution (large disc) to be 180-200 r/m and the rotation (ball milling tank) to be 400-450 r/m, and setting the time to be 100 min.

Detecting chloride ions by a molar method through AgNO₃The standard solution titrates the solution containing the chloride ions, and the dechlorination rate of the PVC under the mechanochemical effect is calculated according to the consumption of the silver nitrate, and the result shows that the dechlorination rate is 88 percent.

Example 10:

the method for treating PVC based on the cooperation of the mechanochemical method and the industrial solid waste specifically comprises the following steps:

at room temperature, mixing the primarily crushed PVC particles with industrial solid waste red mud, putting the mixture into a stainless steel ball-milling tank for sealing, putting the loaded ball-milling tank into a ball mill, wherein the mass ratio of the red mud to the PVC is 25:1, setting the revolution (large disc) to be 150-180 r/m and the rotation (ball-milling tank) to be 350-400 r/m, and the time is 120 min.

Detecting chloride ions by a molar method through AgNO₃The standard solution titrates the solution containing the chloride ions, and the dechlorination rate of the PVC under the mechanochemical effect is calculated according to the consumption of the silver nitrate, and the result shows that the dechlorination rate is 92%.

Example 11:

the method for treating PVC based on the cooperation of the mechanochemical method and the industrial solid waste specifically comprises the following steps:

at room temperature, mixing the PVC particles after primary crushing with industrial solid waste carbide slag, then placing the mixture into a ball milling tank made of stainless steel for sealing, then placing the ball milling tank after loading into a ball mill, wherein the mass ratio of the carbide slag to the PVC is 15:1, the revolution (large disc) is set to be 120-150 r/m, the rotation (ball milling tank) is set to be 260-300 r/m, and the time is 150 min.

The chloride ions are detected by a molar method, the solution containing the chloride ions is titrated by an AgNO3 standard solution, the removal rate of chlorine in PVC under the mechanochemical effect is calculated according to the consumption of silver nitrate, and the result shows that the dechlorination rate is 85%.

Example 12:

the method for treating PVC based on the cooperation of the mechanochemical method and the industrial solid waste specifically comprises the following steps:

mixing the PVC particles after primary crushing and industrial solid waste steel slag at room temperature, then putting the mixture into a ball milling tank made of stainless steel for sealing, then putting the ball milling tank after charging into a ball mill, wherein the mass ratio of the steel slag to the PVC is 10:1, the revolution (large disc) is set to be 80-120 r/min, the rotation (ball milling tank) is set to be 200-250 r/min, and the time is 90 min.

Detecting chloride ions by a molar method through AgNO₃The standard solution titrates the solution containing the chloride ions, and the dechlorination rate of the PVC under the mechanochemical effect is calculated according to the consumption of the silver nitrate, and the result shows that the dechlorination rate is 73 percent.

Example 13

Taking red mud as an example, the influence of experimental parameters on dechlorination rate is explored, and the influence is shown in table 1:

table 1: influence of experimental parameters on dechlorination rate:

grouping	Rotational speed	Particle size	Time	Dechlorination rate
					1	50 to 60 rpm	0.5～1cm	60min	62％
2	400 to 450 rpm	0.5～1cm	60min	81％
					3	50 to 60 rpm	0.1～0.5cm	60min	68％
4	50 to 60 rpm	0.1～0.5cm	120min	73％
					5	400 to 450 rpm	0.5～1cm	120min	83％
6	400 to 450 rpm	0.1～0.5cm	120min	90％

From the above examples, it is concluded that the higher the ball milling speed, the faster the collisions between the milling balls, the more collision energy is generated, and therefore the more energy is transferred and the more energy is applied to the contaminants, thereby converting mechanical energy into chemical energy to remove chlorine from PVC. But the rotating speed is too fast, the materials are easy to stick on the four walls of the ball milling tank, and the ball milling efficiency is reduced.

The ball milling time is short, the particle size of the material is large, the specific surface area is small, the contact area with the grinding ball is small, the energy transfer is less, and the removal effect is poor; the ball milling time is long, the particle size of the material is small, the specific surface area is large, the generated energy is large, the removal effect is good, the sample processing time is too long, the energy consumption is large, and the workload is increased, so that the ball milling efficiency can be improved by the appropriate ball milling time.

The ball-material ratio is small, the contact area between the grinding balls and the materials is small, the energy generated by the collision of the grinding balls is transmitted to the materials less, the utilization rate is low, the energy utilization of the reaction is less, and the degradation effect is poor; along with the increase of the ball-material ratio, the contact area is also increased, and the energy generated by collision between the grinding balls is increased, so that more energy can be transferred to the material, the reaction rate is increased, and meanwhile, the temperature of the material is increased along with the increase of the ball-material ratio, which is favorable for improving the removal efficiency of chlorine in PVC.

CaO is used as an external additive, electrons are transferred by collision among grinding balls and between the grinding balls and a grinding ball tank, and free electrons capture chlorine atoms, so that the aim of degrading and dechlorinating can be fulfilled; the alumina has strong adsorption capacity and catalytic performance; neutral oxidant quartz (SiO)₂) Is a precursor of surface plasmon and is prone to generate radicals with oxidation centers or fracture surfaces during ball milling.

The basic reaction process can be described as follows.

(1) And (4) adsorption and activation. The high energy ball mill mixes the additive and the contaminant sufficiently and brings the solids into intimate contact, while the mechanical forces generated serve to activate the surface activity of the additive.

(2) And (5) performing primary reaction. The free electrons and/or active free radicals generated by the additive react with the organic pollutants to enable the pollutants to undergo a series of reactions such as dechlorination/chlorination, (de) hydrogenation, oxidation reduction, cracking/polymerization and the like.

(3) And (4) mineralization. After sufficient energy is accumulated, organic pollutants are generally reduced into a mixture of amorphous carbon, graphite, light hydrocarbon and the like; chlorine atoms are dissociated from organic contaminants to form inorganic water-soluble Cl^-Finally, dechlorination and complete mineralization of the target pollutants are realized.

The action mode on the organic pollutants is mainly as follows:

(1) and (4) electron transfer. Metal oxides (CaO, MgO, Al)₂O₃、Fe₃O₄Etc.), zero valent metal, etc. in the ball milling process, lattice defect accumulation occurs, and a large amount of free electrons are generated and transferred to organic pollutants for action.

(2) The free radicals act. Mechanical action of additives (e.g. SiO)₂Etc.) the chemical bonds are broken and the constantly exposed radicals act on the organic contaminants.

(3) And (3) nucleophilic substitution reaction. Nucleophilic substitution reaction occurs between the hydride additive and the organic pollutant.

When metal oxide/hydroxide or the like is used as a dehalogenating agent, the principle reaction formula (represented by CaO) of the mechanochemical treatment of chlorine-containing organic matter is:

R-Cl+CaO→CxHy+CaCl₂+H₂O(l)

in a closed container, energy generated by high-speed ball milling operation causes nucleophilic substitution of halide ions and H < - >, so that halogen-containing organic substances and a dehalogenating agent undergo chemical reaction, and meanwhile, macromolecules undergo cracking, reduction and polymerization and are finally converted into micromolecular compounds until simple substance carbon or amorphous carbon, thereby achieving the dehalogenation effect.

The main chemical compositions of the red mud, the carbide slag and the steel slag are industrial wastes containing calcium, aluminum and silicon, and the requirements of the red mud, the carbide slag and the steel slag as a dehalogenation agent are met.

Reference throughout this specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment described generally in this application. The appearances of the same phrase in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the scope of the invention to effect such feature, structure, or characteristic in connection with other embodiments.

Although the invention has been described herein with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More specifically, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure/claims of this application. In addition to variations and modifications in the component parts and/or arrangements, other uses will also be apparent to those skilled in the art.