Method for removing mercury by incineration of medical waste, mercury removal adsorbent and its use

Abstract

This invention provides a method for removing mercury by incinerating medical waste, a mercury removal adsorbent, and its use. [Solution] The method for removing mercury by incinerating medical waste includes the step of spraying a mercury removal adsorbent solution onto the surface of the medical waste and then incinerating it. The mercury removal adsorbent of the present invention contains CaCl2, CaBr2 and KI, and by combining these three, Hg in exhaust gas is removed. 0 This significantly improves the removal of Hg. The mercury removal adsorbent further contains MgO, which acts as a basic neutralizing agent, neutralizing acidic gases such as HCl, HBr, and HI generated by incineration, thereby providing a more stable reaction environment for halogen radicals, and thus Hg 0 It reduces the potential inhibition of the oxidation chain reaction and improves the oxidation rate. At the same time, the presence of MgO plays a role in reducing the dioxin concentration in the exhaust gas and, as a neutralizing agent, reduces acid dew point corrosion, thereby reducing equipment corrosion caused by exhaust gas.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical waste treatment, and particularly relates to a method for removing mercury by incinerating medical waste, a mercury removal adsorbent, and its use.

Background Art

[0002] Medical waste incineration is an important method for realizing the reduction and harmless treatment of solid waste. However, mercury (Hg), a heavy metal contained in incineration flue gas, is a typical pollutant, and its emission poses a serious threat to the ecological environment and human health. In the prior art, mercury in incineration flue gas mainly exists in the forms of elemental mercury (Hg 0 ), divalent mercury (Hg 2+ ), and particulate mercury (Hg p ). Hg 2+ can be removed by a wet deacidification tower, and Hg p can be removed by a dust collector. However, Hg 0 has stable chemical properties and is hardly soluble in water, so it cannot be effectively removed by ordinary devices and has become a major bottleneck in mercury emission control.

[0003] Currently, for the removal of Hg 0 , a single halogen-based mercury removal adsorbent (such as calcium bromide) is usually used. However, there are problems such as limited oxidation rate of Hg 0 , and it is impossible to simultaneously achieve the reduction of dioxin emission.

[0004] Therefore, developing a synergistic mercury removal technology for incineration flue gas with high mercury removal efficiency and suppressing the generation of dioxin has become an urgent technical problem to be solved in this field.

Summary of the Invention

[0005] In view of the defects existing in the prior art, the present invention provides a method for removing mercury by incinerating medical waste, a mercury removal adsorbent, and its use. The mercury removal adsorbent adopted in the present invention contains CaCl2, CaBr2 and KI. By compounding these three components, the oxidation rate of Hg 0 is greatly improved, the emission of dioxin is reduced, and the high-efficiency removal of Hg 0 in the flue gas discharged from the incineration of medical waste is realized. Furthermore, the problems of acidification of flue gas, corrosion of equipment and dioxin emission are solved simultaneously.

[0006] In order to achieve the above object, the present invention adopts the following technical means. The present invention provides a mercury removal adsorbent containing CaCl2, CaBr2 and KI, wherein the mass ratio of CaCl2, CaBr2 and KI is (4.5-5.5):(0.8-1.2):(0.05-0.15).

[0007] Preferably, the mercury removal adsorbent further contains MgO.

[0008] Preferably, the mass of the MgO in the mercury removal adsorbent is 1-4% of the total mass of CaCl2, CaBr2 and KI.

[0009] Preferably, the mass ratio of CaCl2, CaBr2 and KI is 5.0:1.0:0.15.

[0010] Preferably, the mass of the MgO in the mercury removal adsorbent is 2% of the total mass of CaCl2, CaBr2 and KI.

[0011] In a second aspect, the present invention further provides the use of the above mercury removal adsorbent in the removal of Hg 0 and dioxin in the flue gas discharged from the incineration of medical waste.

[0012] In a third aspect, a method for removing mercury by incinerating medical waste is further provided. The method includes a step of adding the above mercury removal adsorbent into water to obtain a mercury removal adsorbent solution, The steps include: spraying the mercury removal adsorbent solution onto the surface of the medical waste, and then incinerating it; Includes.

[0013] The preferred incineration temperature is 600-1000°C.

[0014] Preferably, the ratio of the total chemical equivalents of bromine, chlorine, and iodine to the chemical equivalent of mercury in the medical waste is (1000-4000):1. Here, the total chemical equivalents of bromine, chlorine, and iodine are given by the following formula:

number

number

[0015] Preferably, the mass fraction of the mercury removal adsorbent in the mercury removal adsorbent solution is 1 to 10%.

[0016] The present invention provides a method for removing mercury by incinerating medical waste, a mercury removal adsorbent, and its use, which have the following advantages compared to the prior art. 1. The present invention relates to a method for removing mercury by incinerating medical waste, which involves adding a mercury-removing adsorbent to water to obtain a mercury-removing adsorbent solution, spraying the mercury-removing adsorbent solution onto the surface of the medical waste, and then incinerating it. The mercury-removing adsorbent of the present invention contains CaCl2, CaBr2, and KI, and by combining these three, Hg in the exhaust gas is removed. 0 This significantly improves the removal of Hg 0The oxidation of Hg is promoted by the generation of radicals, and Br· radicals promote Hg 0 Oxidation of (bromine radical Br· is Hg 0 divalent mercury (Hg 2+ The reaction rate of oxidizing to ) is the fastest, and Hg in mercury removal adsorbents 0 It is the main factor in the oxidation of Hg. It shows particularly excellent oxidizing effects in the medium to high temperature range (600-900°C). Although the activity of the Cl· radical is somewhat weak, Cl is usually the most abundant in exhaust gas and provides a sustained oxidizing atmosphere. Iodide ions in KI alter the thermal decomposition pathway of CaBr2 / CaCl2, allowing the release of active halogen radicals at lower temperatures, and the I· radical has high activity, causing a stronger chain reaction. Therefore, the synergistic action of bromine-chlorine-iodine leads to the oxidation of Hg. 0 This enables faster, more complete oxidation with broader temperature adaptability. At the same time, the mercury removal adsorbent of the present invention can significantly reduce the dioxin concentration in exhaust gas through a bromine-chlorine-iodine ternary complex, reducing dioxin emissions by 35.6% compared to calcium bromide alone. 2. The mercury removal adsorbent of the present invention further contains MgO, which functions as a basic neutralizing agent. Although MgO itself does not directly participate in oxidation, it neutralizes acidic gases such as HCl, HBr, and HI generated by incineration, thereby providing a more stable and less interfering reaction environment for halogen radicals (Br·, Cl·, I·). This reduces the potential inhibition of the oxidation chain reaction of HgO and improves the oxidation rate. At the same time, since the suppression of dioxins mainly depends on the destruction of precursors by halogen radicals, the dioxin concentration is further reduced in the presence of MgO. In addition, as a basic neutralizing agent, MgO reacts with hydrogen halides (HCl, HBr, HI) to produce corresponding salts, thereby reducing acid dew point corrosion and reducing equipment corrosion caused by exhaust gases. [Brief explanation of the drawing]

[0017] To more clearly illustrate embodiments of the present invention or technical means in the prior art, the drawings used in the description of embodiments or the prior art will be briefly described below. Clearly, the drawings described below represent only a few embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0018] [Figure 1] This figure shows the effect of different mercury removal adsorbents in Example 1 and Comparative Example 1 on the Hg0 oxidation rate under different incineration temperatures and different equivalent ratios. [Modes for carrying out the invention]

[0019] To facilitate understanding of the present invention, it will be described more comprehensively below in combination with specific embodiments. Specific embodiments will show preferred examples of the present invention. However, the present invention can be implemented in a variety of forms and is not limited to the embodiments described herein. The purpose of providing these embodiments is to provide a more complete and comprehensive understanding of the disclosure of the present invention.

[0020] The order in which the following embodiments are described is not limited to any preferred order. Furthermore, in this description, the term “including” means “including but not limited to.” While various embodiments of the present invention may be expressed in range form, such range form is for convenience and brevity only and should not be interpreted as a strict limitation on the scope of the invention. Therefore, such range descriptions should be considered to specifically disclose all possible subranges and single numerical values ​​within that range. For example, a range description from 1 to 6 is considered to specifically disclose subranges such as 1 to 3, 1 to 4, 1 to 5, 2 to 4, 2 to 6, 3 to 6, and single numerical values ​​such as 1, 2, 3, 4, 5, and 6, and applies similarly regardless of the range. Also, where a numerical range is indicated in this specification, it means that any numerical value (fraction or integer) within that range is included.

[0021] The present invention provides a mercury removal adsorbent. The mercury removal adsorbent comprises CaCl2, CaBr2, and KI, with a mass ratio of CaCl2, CaBr2, and KI of (4.5~5.5):(0.8~1.2):(0.05~0.15).

[0022] The mercury removal adsorbent of the present invention contains CaCl2, CaBr2, and KI, and by combining these three, Hg in exhaust gas is removed. 0 This significantly improves the removal of Hg. Specifically, halogens promote the oxidation of Hg by generating radicals, and Hg by Br radicals. 0 Oxidation (bromine radical Br· is Hg0 is divalent mercury (Hg 2+ The reaction rate of oxidizing to ) is the fastest, and Hg in mercury removal adsorbents 0 It is the main factor in the oxidation of Hg. It shows particularly excellent oxidizing effects in the medium to high temperature range (600-900°C). Although the activity of the Cl· radical is somewhat weak, Cl is usually the most abundant in exhaust gas and provides a sustained oxidizing atmosphere. Iodide ions in KI alter the thermal decomposition pathway of CaBr2 / CaCl2, releasing active halogen radicals at lower temperatures, and the I· radical has high activity, causing a stronger chain reaction. Therefore, the synergistic action of bromine-chlorine-iodine leads to the oxidation of Hg. 0 This enables faster, more complete oxidation with broader temperature adaptability. At the same time, the mercury removal adsorbent of the present invention can significantly reduce dioxin concentration through a bromine-chlorine-iodine ternary complex, reducing dioxin emissions by 35.6% compared to calcium bromide alone.

[0023] In some examples, MgO is also included.

[0024] In some examples, the mass of MgO is 1-4% of the total mass of CaCl2, CaBr2, and KI.

[0025] Furthermore, the mercury removal adsorbent of the present invention contains MgO, which functions as a basic neutralizing agent. Although MgO itself does not directly participate in oxidation, it neutralizes acidic gases such as HCl, HBr, and HI generated by incineration, thereby providing a more stable and less interfering reaction environment for halogen radicals (Br·, Cl·, I·). This reduces the potential inhibition of the oxidation chain reaction of HgO and improves the oxidation rate. At the same time, since the suppression of dioxins mainly depends on the destruction of precursors by halogen radicals, the dioxin concentration is further reduced in the presence of MgO. In addition, as a basic neutralizing agent, MgO reacts with hydrogen halides (HCl, HBr, HI) to produce corresponding salts, thereby reducing acid dew point corrosion and reducing equipment corrosion caused by exhaust gases.

[0026] In some examples, the mass ratio of CaCl2, CaBr2, and KI is 5.0:1.0:0.1.

[0027] In some examples, the mass of MgO is 2% of the sum of the masses of CaCl2, CaBr2, and KI.

[0028] Based on the same concept, the present invention further relates to the removal of mercury from the exhaust gas of medical waste incineration. 0 It also provides for use in the removal of dioxins.

[0029] Based on the same concept of invention, the present invention further provides a method for removing mercury by incinerating medical waste, comprising the following steps. S1: The mercury removal adsorbent is added to water to obtain a mercury removal adsorbent solution. S2: After spraying the mercury removal adsorbent solution onto the surface of the medical waste, it is incinerated.

[0030] The present invention relates to a method for removing mercury by incinerating medical waste, in which a mercury-removing adsorbent solution is sprayed onto the surface of the medical waste before incineration, and the medical waste generates exhaust gas during incineration. The mercury-removing adsorbent contains CaCl2, CaBr2, and KI, and by combining these three, the Hg in the exhaust gas is removed. 0Oxidation rate (Hg 0 divalent mercury (Hg 2+ This significantly improves oxidation and also dramatically reduces the dioxin concentration in exhaust gas through a ternary bromine-chlorine-iodine complex.

[0031] In some examples, the incineration temperature is 600 to 1000°C.

[0032] In some examples, the ratio of the total chemical equivalents of bromine, chlorine, and iodine to the chemical equivalent of mercury in the medical waste is (1000-4000):1. Here, the method for calculating the total chemical equivalents of bromine, chlorine, and iodine is:

number

number

[0033] In the above formula, M a This indicates the mass of CaCl2 in the mercury removal adsorbent solution, M a ×0.639 represents the mass of the element Cl in CaCl2 (the mass fraction of the element Cl in CaCl2 is 63.9%). b This indicates the mass of CaBr2 in the mercury removal adsorbent solution, and M b ×0.799 represents the mass of Br in CaBr2 (the mass fraction of Br in CaBr2 is 79.9%). c The value of ∫ represents the mass of KI in the mercury removal adsorbent solution, and Mc × 0.764 represents the mass of element I in KI (the mass fraction of element I in KI is 76.4%).

[0034] In some cases, the mass of mercury in medical waste was measured by microwave-resolved atomic fluorescence spectroscopy, specifically employing the national standard HJ 702-2014 "Measurement of mercury, arsenic, selenium, bismuth, and antimony in solid waste by microwave-resolved atomic fluorescence spectroscopy."

[0035] In some examples, the mass fraction of the mercury removal adsorbent in the mercury removal adsorbent solution is 1 to 10%.

[0036] In some examples, particulate mercury (Hg) in the exhaust gas produced by incineration p ) is removed by a dust collector, Hg 2+ This can be removed by a wet deoxidation tower.

[0037] The following describes the method for removing mercury by incineration of medical waste, the mercury removal adsorbent, and its use in the present invention with specific examples. This section further explains the content of the present invention in combination with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means employed in the examples are common means known to those skilled in the art. Unless otherwise specified, the reagents, methods, and apparatus employed in the present invention are common reagents, methods, and apparatus to those skilled in the art.

[0038] The Hg element content in the medical waste used in the following examples and comparative examples is 10 mg / kg (i.e., the mass of Hg element in 1 kg of medical waste is 10 mg).

[0039] Example 1 This embodiment provides a mercury removal adsorbent comprising CaCl2, CaBr2, and KI, with a mass ratio of 5:1:0.1 between CaCl2, CaBr2, and KI.

[0040] This embodiment further provides a method for removing mercury by incinerating medical waste, and includes the following steps. S1: The mercury removal adsorbent from Example 1 is added to water to obtain a mercury removal adsorbent solution. S2: After spraying the mercury removal adsorbent solution onto the surface of the medical waste, it is incinerated. Here, the incineration temperature is 900°C, the mass fraction of the mercury-removing adsorbent in the mercury-removing adsorbent solution is 5%, and the ratio of the total chemical equivalents of bromine, chlorine, and iodine in the mercury-removing adsorbent solution to the chemical equivalent of mercury in the medical waste is (1000-4000):1 (1000:1, 2000:1, 3000:1, and 4000:1, respectively).

[0041] Comparative Example 1 This comparative example provides a mercury removal adsorbent that is CaBr2.

[0042] This embodiment further provides a method for removing mercury by incinerating medical waste, and includes the following steps. S1: The mercury removal adsorbent from Comparative Example 1 is added to water to obtain a mercury removal adsorbent solution. S2: After spraying the mercury removal adsorbent solution onto the surface of the medical waste, it is incinerated. Here, the incineration temperature is 800-1000°C (800°C, 900°C, and 1000°C respectively), the mass fraction of the mercury removal adsorbent in the mercury removal adsorbent solution is 5%, and the chemical equivalent of Br in the mercury removal adsorbent solution is (the chemical equivalent of Br is,

number

[0043] According to the method of Example 1, under incineration conditions at a temperature of 900°C, different amounts of mercury removal adsorbent were used to remove Hg 0 The effect on oxidation rate was evaluated. Furthermore, following the method of Comparative Example 1, a single mercury removal adsorbent, CaBr2, was used to evaluate Hg under different incineration temperatures and chemical equivalent ratios. 0 The effect on oxidation rate was evaluated. Here, Hg 0The method for measuring the oxidation rate is as follows: Medical waste (without the addition of an adsorbent solution) is incinerated at the same temperature (e.g., 900°C) for 2 hours, and the Hg in the exhaust gas is measured. 0 Let the mass be m1, and medical waste to which an adsorbent solution has been added was incinerated at the same temperature (e.g., 900°C) for 2 hours, and the Hg in the exhaust gas was measured. 0 Let the mass of be m², Hg 0 Oxidation rate = (m1-m2) / m1 × 100%. Hg in exhaust gas 0 The method for measuring mass is as follows: First, the exhaust gas is passed through a NaHCO3 solution to remove SO2, and then introduced into an RA-915M mercury analyzer to measure the Hg in the sample incinerated exhaust gas. 0 The concentration was measured and Hg was detected using an RA-915M mercury analyzer. 0 The time-dependent curve of the concentration is obtained, this concentration is integrated over time, and then multiplied by the exhaust gas flow rate to calculate the mass of Hg0 in the exhaust gas.

[0044] The measurement results are shown in Figure 1. In Figure 1, the horizontal axis shows the ratio of the total chemical equivalents of bromine-chlorine-iodine (or chemical equivalent of Br) to the chemical equivalent of mercury in medical waste. In Figure 1, the bromine-chlorine-iodine ternary composite agent at 900°C, i.e., the mercury removal adsorbent in Example 1, under different chemical equivalent ratio conditions at an incineration temperature of 900°C, is Hg 0 The effect on oxidation rate is shown. As shown in Figure 1, under the conditions of a single calcium bromide mercury removal adsorbent, Hg 0 The oxidation rate is highest. On the other hand, under high temperature conditions of 1000°C, Hg 0 The oxidation rate decreases compared to 800°C and 900°C. This is mainly because, according to thermodynamic equilibrium calculations, mercury in medical waste is mainly Hg during the high-temperature combustion process. 0 It is released in the form of Hg, and the higher the temperature, the greater the amount of Hg. 0 This is because the proportion of Hg increases as the temperature of the incineration exhaust gas decreases. 0 Hg is produced in exhaust gas through a series of complex homogeneous and heterogeneous reactions. 2+ It transforms into this. Under high temperature conditions of 1000℃, the proportion of Hg0 in the exhaust gas is high, so Hg 0 The oxidation rate increases.

[0045] Under the conditions of a single calcium bromide mercury adsorbent, when the mass ratio of bromine to mercury increases from 1000 to 2000 under the conditions of 800°C, 900°C, and 1000°C, the amount of Hg in the incineration exhaust gas increases. 0 The oxidation rate improves significantly. On the other hand, if the chemical equivalent ratio of bromine to mercury increases further, Hg 0 The increase in oxidation rate is gradual, and the change is small.

[0046] Under the conditions of the bromine-chlorine-iodine ternary complex mercury removal adsorbent, its Hg 0 The oxidizing effect was confirmed to be superior to that of a single calcium bromide mercury removal adsorbent. As the chemical equivalent ratio of the bromine-chlorine-iodine adsorbent to mercury increased from 1000 to 4000, Hg 0 The oxidation rates improved by 8.13%, 4.69%, 3.51%, and 1.46%, respectively, compared to a single calcium bromide adsorbent. When the mass ratio of bromine-chlorine-iodine adsorbent to mercury was 4000, Hg 0 The oxidation rate reaches almost 100%, and a chemical equivalent ratio of 2000 between the bromine-chlorine-iodine adsorbent and mercury is a relatively ideal addition ratio.

[0047] Example 2 This embodiment provides a mercury removal adsorbent containing CaCl2, CaBr2, and KI, with the mass ratio of CaCl2, CaBr2, and KI being (4.5~5.5):(0.8~1.2):(0.05~0.15). The specific formulation is shown in Table 1. This embodiment further provides a method for removing mercury by incinerating medical waste, and includes the following steps. S1: The mercury removal adsorbent from Example 2 is added to water to obtain a mercury removal adsorbent solution. S2: After spraying the mercury removal adsorbent solution onto the surface of the medical waste, it is incinerated. Here, the incineration temperature is 900°C, the mass fraction of the mercury-removing adsorbent in the mercury-removing adsorbent solution is 5%, and the ratio of the total chemical equivalents of bromine, chlorine, and iodine in the mercury-removing adsorbent solution to the chemical equivalent of mercury in the medical waste is 2000:1.

[0048] Following the method of Example 2, the effect of different mass ratios of CaCl2, CaBr2, and KI in the mercury removal adsorbent on the Hg0 oxidation rate was investigated under conditions of incineration temperature of 900°C and a ratio of the total chemical equivalents of bromine-chlorine-iodine to the chemical equivalents of mercury in medical waste of 2000:1. The results are shown in Table 1.

[0049] Table 1: Mass ratios of different CaCl2, CaBr2, and KI in Hg 0 Influence on oxidation rate [Table 1]

[0050] As can be seen from Table 1 above, bromine is Hg at high temperatures. 0 CaBr2 is the leading factor in oxidation, and when it is deficient, Hg 0 It is a major limiting factor in oxidation. Iodine acts as a highly efficient catalyst, significantly lowering the release temperatures of Br and Cl and improving their activity. A positive synergistic effect exists between Br and I, and changes in their content affect Hg 0 It is very sensitive to oxidation levels. Cl can provide a sustained and stable oxidizing atmosphere to the system, but the effect of CaCl2 is weaker than that of CaBr2. Therefore, the ratio with Br must be maintained within a certain range, as excess can dilute the active ingredients. Overall, CaCl2:CaBr2:KI = 5:1:0.1 is Hg 0 This is the optimal blending ratio for oxidation.

[0051] Example 3 This embodiment provides a mercury removal adsorbent comprising CaCl2, CaBr2, KI, and MgO, with a mass ratio of 5:1:0.1 for CaCl2, CaBr2, and KI, and the mass of MgO being 1-4% of the total mass of CaCl2, CaBr2, and KI (specifically 1%, 2%, 3%, and 4%, respectively). This embodiment further provides a method for removing mercury by incinerating medical waste, and includes the following steps. S1: The mercury removal adsorbent from Example 3 is added to water to obtain a mercury removal adsorbent solution. S2: After spraying the mercury removal adsorbent solution onto the surface of the medical waste, it is incinerated. Here, the incineration temperature is 900°C, the mass fraction of the mercury-removing adsorbent in the mercury-removing adsorbent solution is 5%, and the ratio of the total chemical equivalents of bromine, chlorine, and iodine in the mercury-removing adsorbent solution to the chemical equivalent of mercury in the medical waste is 2000:1.

[0052] Following the method of Example 3, the effect of different mass fractions of MgO added to the mercury removal adsorbent on the Hg0 oxidation rate was investigated under conditions of incineration temperature of 900°C and a ratio of the total chemical equivalents of bromine-chlorine-iodine to the chemical equivalents of mercury in medical waste of 2000:1. The results are shown in Table 2 below.

[0053] Table 2: Effect of different mass fractions of MgO addition on Hg0 oxidation rate [Table 2]

[0054] As can be seen from Table 2, by adding an appropriate amount of MgO, MgO itself becomes Hg 0 Although it does not directly oxidize HgO, neutralizing the acidic gas provides a more stable and less interfering reaction environment for halogen radicals (Br·, Cl·, I·), thereby reducing the potential inhibition of the chain reaction of HgO oxidation and improving the oxidation rate. The optimal condition is when the amount of MgO added is 2%, at which point the acidic gas is effectively neutralized, and the occupation of adsorption sites on the reactor surface by the acidic gas is reduced, which is expected to improve the gas-solid reaction efficiency. On the other hand, if the amount of MgO added exceeds 3%, the excess MgO reduces the concentration of the active halogen component per unit mass due to physical dilution, and may also change the dispersion characteristics of the mercury removal adsorbent mixture, which may offset the positive effects of environmental optimization and Hg 0 The oxidation rate was reduced. From the above, it can be seen that adding 2% MgO is the optimal condition for a ternary composite mercury removal adsorbent with a ratio of CaCl2:CaBr2:KI = 5:1:0.1.

[0055] Example 4 This embodiment provides a mercury removal adsorbent. The mercury removal adsorbent contains CaCl2, CaBr2, KI, and MgO, with a mass ratio of 5:1:0.1 for CaCl2, CaBr2, and KI, and the mass of MgO is 2% of the sum of the masses of CaCl2, CaBr2, and KI. This embodiment further provides a method for removing mercury by incinerating medical waste, and includes the following steps. S1: The mercury removal adsorbent from Example 4 is added to water to obtain a mercury removal adsorbent solution. S2: After spraying the mercury removal adsorbent solution onto the surface of the medical waste, it is incinerated. Here, the incineration temperature is 900°C, the mass fraction of the mercury-removing adsorbent in the mercury-removing adsorbent solution is 5%, and the ratio of the total chemical equivalents of bromine, chlorine, and iodine in the mercury-removing adsorbent solution to the chemical equivalent of mercury in the medical waste is 2000:1.

[0056] Example 5 This embodiment provides a method for removing mercury by incinerating medical waste. The method includes the following steps. S1: A mercury removal adsorbent is added to water to obtain a mercury removal adsorbent solution. The mercury removal adsorbent (without MgO) contains CaCl2, CaBr2, and KI, and the mass ratio of CaCl2, CaBr2, and KI is 5:1:0.1. S2: After spraying the mercury removal adsorbent solution onto the surface of the medical waste, it is incinerated. Here, the incineration temperature is 900°C, the mass fraction of the mercury-removing adsorbent in the mercury-removing adsorbent solution is 5%, and the ratio of the total chemical equivalents of bromine-chlorine-iodine to the chemical equivalents of mercury in the medical waste is 2000:1.

[0057] Comparative Example 2 This comparative example provides a method for removing mercury by incinerating medical waste. The method includes the following steps. S1: A mercury-removing adsorbent is added to water to obtain a mercury-removing adsorbent solution. Here, the mercury-removing adsorbent is CaBr2. S2: After spraying the mercury removal adsorbent solution onto the surface of the medical waste, it is incinerated. Here, the incineration temperature is 900°C, the mass fraction of the mercury removal adsorbent in the mercury removal adsorbent solution is 5%, and the ratio of the chemical equivalent of Br in the mercury removal adsorbent solution to the chemical equivalent of mercury in the medical waste is 2000:1.

[0058] Comparative Example 3 This comparative example provides a method for removing mercury by incinerating medical waste. The method includes the following steps. Medical waste is incinerated. The incineration temperature is 900°C.

[0059] Following the methods of Examples 4-5 and Comparative Examples 2-3, the materials were incinerated for 2 hours each, and the dioxin concentration in the exhaust gas was measured to evaluate the effect of different mercury removal adsorbents on the dioxin concentration in the exhaust gas. The results are shown in Table 3.

[0060] Table 3: Effects of different mercury removal adsorbents on dioxin concentrations in exhaust gas [Table 3]

[0061] Table 3 shows ng TEQ / Nm 3 This refers to the total toxic equivalent of dioxins contained in a unit volume (1 cubic meter) of exhaust gas, with nanograms (ng) as the unit.

[0062] As can be seen from Table 3, the bromine-chlorine-iodine ternary mercury removal adsorbent can significantly reduce dioxin concentrations, reducing dioxin emissions by 35.6% compared to single calcium bromide. The presence of MgO efficiently neutralizes acidic gases such as HCl, HBr, and HI generated by incineration, and provides a more stable and less interfering reaction environment for halogen radicals (Br·, Cl·, I·). On the other hand, since the suppression of dioxin generation mainly depends on the destruction of precursors by halogen radicals, dioxin concentrations are further reduced in the presence of MgO.

[0063] The technical features in the embodiments described above can be combined in any way, and for the sake of brevity, not all possible combinations of the technical features in the embodiments described above are described. However, as long as these combinations of technical features are not contradictory, they should be understood to fall within the scope described herein.

[0064] The foregoing are merely preferred embodiments of the present application and serve to illustrate the technical principles thereof. These descriptions are for illustrative purposes only and should not be interpreted as limiting the scope of protection of the present application. Any modifications, equivalent substitutions and improvements made thereto, as well as other specific embodiments that a person skilled in the art could easily conceive, based on the spirit and principles of the present application, shall be included within the scope of protection of the present application.

Claims

1. A mercury removal adsorbent, CaCl ２ CaBr ２ and KI, CaCl ２ And, CaBr ２ A mercury removal adsorbent characterized by having a mass ratio of (4.5-5.5):(0.8-1.2):(0.05-0.15) with respect to KI.

2. The mercury removal adsorbent according to claim 1, further characterized by containing MgO.

3. The mass of the aforementioned MgO is CaCl ２ CaBr ２ The mercury removal adsorbent according to claim 2, characterized in that it is 1 to 4% of the total mass of KI.

4. The aforementioned CaCl ２ And, CaBr ２ The mercury removal adsorbent according to claim 1, characterized in that the mass ratio of KI is 5.0:1.0:0.

1.

5. The mass of the MgO is 2% of the total mass of CaCl ２ , CaBr ２ and KI, and the mercury removal adsorbent according to claim 3 is characterized in that.

6. Hg in exhaust gas from medical waste incineration ０ and the use of a mercury removal adsorbent according to any one of claims 1 to 5 in the removal of dioxins.

7. A method for removing mercury by incinerating medical waste, A step of adding a mercury removal adsorbent according to any one of claims 1 to 5 to water to obtain a mercury removal adsorbent solution, The steps include: spraying the mercury removal adsorbent solution onto the surface of the medical waste, and then incinerating it; A method characterized by including

8. The method according to claim 7, characterized in that the incineration temperature is 600 to 1000°C.

9. The ratio of the total chemical equivalents of bromine, chlorine, and iodine in the mercury removal adsorbent solution to the chemical equivalent of mercury in the medical waste is (1000-4000):

1. Here, the total chemical equivalents of bromine, chlorine, and iodine are given by the following formula: [Math 1] It is calculated by the formula, where M ａ CaCl in a mercury removal adsorbent solution ２ It shows the mass of M ｂ CaBr in mercury removal adsorbent solution ２ It shows the mass of M ｃ This indicates the mass of KI in the mercury removal adsorbent solution. The chemical equivalent of mercury in medical waste is given by the following formula: [Math 2] It is calculated by the formula, where M Ｈｇ The method according to claim 7, characterized in that indicates the mass of mercury element in medical waste.

10. The method according to claim 7, characterized in that the mass fraction of the mercury removal adsorbent in the mercury removal adsorbent solution is 1 to 10%.

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