Vitrification treatment method for hazardous solid waste containing arsenic

Abstract

The present invention relates to the field of solid waste treatment, and discloses a vitrification treatment method for arsenic-containing hazardous solid waste. The method comprises: mixing auxiliary vitrified oxide with arsenic-containing hazardous solid waste residue to prepare pre-mixed slag, and the pre-mixed slag meets the following conditions: the pre-mixed slag is medium (FeO x +Al 2 O 3 ) content ≥ 20wt%, Fe(Ⅲ) / ∑Fe ≥ 50%, silica acidity ≥ 1.5, oxygen-silicon ratio ≤ 3.5; silica acidity is expressed as K, when 1.5≤K<1.8, ω As ≤2.5wt%; when 1.8≤K<2.0,ω As ≤3.5wt%. When 2.0≤K≤2.5, ω As ≤5wt%; the upper limit of each of the other heavy metals is ω Me =(3.26K-4.08)wt%, where K = 1.5-2.5, and the upper limit of Ni content in slag is (0.2-0.25)·ω Me ; Then the pre-mixed slag is melted and rapidly cooled. This method has good treatment effect.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste treatment, and in particular to a vitrification treatment method for arsenic-containing hazardous solid waste. Background Art

[0002] Solid waste vitrification is a method of treating solid waste to make it harmless. Solid waste is melted at high temperature (or some vitrified substances are added to it, such as broken glass, carbonate-silicon dioxide mixture) to form a glass solid. Vitrification is a common treatment method for arsenic-containing hazardous waste.

[0003] Existing research, such as "Shan Taoyun, Liu Queming, Liao Guangrong, Deng Weihua. Research on harmless treatment and resource technology of arsenic mixed salt [J]. Mineral Resources and Geology, 2013, 27 (S1): 68-71." The method disclosed in the content is mainly as follows: (1) waste glass bottles or slag are mixed with a certain amount of arsenic mixed salt, and melted at high temperature to form a glass solid body, and its toxic leaching test can meet the standard of general solid waste. (2) The melting temperature of the solid body is 1100℃~1300℃, and the time is 60~120min. The arsenic content in the solid body is: arsenic ≤6.0% when waste glass bottles are used as carriers, and arsenic ≤4.5% when slag is used as carriers. The toxic leaching test results of the solid body are arsenic ≯5.0mg / L, which meets the national general solid waste requirements. (3) The solid body obtained by using slag as carrier is used as raw material for underground filling cement production, which is safe and environmentally friendly, and its usage is very large. This method can fundamentally render arsenic-containing mixed salts harmless; the solidified body obtained by using waste glass bottles as carriers can be safely stacked or used as a clarifier for some glass production.

[0004] However, the above method has the following problems: 1. This method meets the leaching toxicity identification requirements of GB 5085.3-2007 Hazardous Waste Identification Standard, GB / T 41015-2021- is more stringent than GB 5085.3-2007, and the comparative document 1 does not necessarily meet GB / T 41015-2021 "Technical Requirements for Solid Waste Vitrification Treatment Products"; 2. It is simply a simple material mixing and smelting, and only controls the arsenic content, and does not examine the impact of other factors on the vitrification treatment effect.

[0005] In view of this, this application is hereby filed. Summary of the invention

[0006] The purpose of the present invention is to provide a vitrification treatment method for arsenic-containing hazardous solid waste.

[0007] The present invention is achieved in that:

[0008] In a first aspect, the present invention provides a method for vitrification treatment of arsenic-containing hazardous solid waste, comprising:

[0009] (1) The auxiliary vitrified oxide is mixed with arsenic-containing hazardous solid waste to prepare a pre-mixed slag, and the pre-mixed slag meets the following conditions:

[0010] The pre-mixed slag is CaO-FeO x -Al 2 O 3 -Me x O y -SiO 2 The slag is mainly composed of multiple systems, among which (FeO x +Al 2 O 3 ) content ≥ 20wt%, Fe(III) / ∑Fe ≥ 50%, silica acidity ≥ 1.5, oxygen-silicon ratio ≤ 3.5;

[0011] Silicic acidity is expressed as K. When 1.5≤K<1.8, ω As ≤2.5wt%; when 1.8≤K<2.0,ω As ≤3.5wt%. When 2.0≤K≤2.5, ω As ≤5wt%;

[0012] The upper limit of each heavy metal that needs to be tested for leaching toxicity except Ni is ω Me =(3.26K-4.08)wt%, where K = 1.5-2.5, and the upper limit of Ni content in slag is (0.2-0.25)·ω Me ;

[0013] Silica acidity refers to the total number of moles of oxygen in acidic oxides / the total number of moles of oxygen in alkaline oxides. Alumina and chromium oxide in slag are not included in the calculation of silica acidity. Ferric oxide is calculated as ferrous oxide.

[0014] The oxygen-silicon ratio refers to the molar number of oxygen in the slag / the sum of the molar numbers of silicon and arsenic in the slag. The oxygen in the alumina in the slag is not included in the calculation of the oxygen-silicon ratio.

[0015] (2) The pre-mixed slag is smelted, and after being fully melted, it is rapidly cooled to obtain rapidly cooled slag.

[0016] In an optional embodiment, the smelting temperature is 50-200° C. higher than the hemispherical temperature of the pre-mixed slag, and the smelting temperature is maintained for at least 30 minutes.

[0017] In an optional embodiment, the melt viscosity is controlled to be ≤2.0 Pa·s.

[0018] In an optional embodiment, the melt viscosity is controlled to be ≤1.0 Pa·s.

[0019] In an optional embodiment, the vitrification degree of the pre-mixed slag is ≥ 85% after the rapid cooling treatment.

[0020] In an optional embodiment, the rapid cooling method includes water quenching, rapid air cooling or spray cooling.

[0021] In an alternative embodiment, the auxiliary vitrified oxide includes at least one of silicon dioxide, calcium oxide, iron oxide, and aluminum oxide.

[0022] In an optional embodiment, the smelting atmosphere is an oxidizing atmosphere.

[0023] In an optional embodiment, after obtaining the quenched slag, the process further comprises:

[0024] (3) The composition of the quenched slag is analyzed and tested in accordance with GB / T 41015-2021 "Technical Requirements for Products of Solid Waste Vitrification Treatment". If the indicators are unqualified, the quenched slag is treated as arsenic-containing hazardous solid waste slag for ingredient correction and steps (1) to (3) are repeated.

[0025] The present invention has the following beneficial effects:

[0026] The vitrification treatment method for arsenic-containing hazardous solid waste provided in the embodiment of the present application regulates the silica acidity, oxygen-silicon ratio and the ratio of trivalent iron to total iron content so that these conditions are within a suitable range. On this premise, the upper limit content of arsenic and other heavy metals is studied. In the process of vitrification treatment of arsenic-containing hazardous solid waste, the chemical composition of the pre-mixed slag is controlled to meet the above requirements, which has a good treatment effect on arsenic-containing hazardous solid waste and can ensure that the treated vitrified slag meets GB / T41015-2021 "Technical Requirements for Solid Waste Vitrification Treatment Products". The method provided in this application has a better treatment effect than the existing treatment method that only requires the arsenic content. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0028] The vitrification treatment method for arsenic-containing hazardous solid waste provided by an embodiment of the present invention is described in detail below.

[0029] The vitrification treatment method for arsenic-containing hazardous solid waste provided by the embodiment of the present invention comprises:

[0030] (1) The auxiliary vitrified oxide is mixed with arsenic-containing hazardous solid waste to prepare a pre-mixed slag, and the pre-mixed slag meets the following conditions:

[0031] The pre-mixed slag is CaO-FeO x -Al 2 O 3 -Me x O y -SiO 2 The slag is mainly composed of multiple systems, among which (FeO x +Al 2 O 3 ) content ≥ 20wt%, Fe(III) / ∑Fe ≥ 50%, silica acidity ≥ 1.5, oxygen-silicon ratio ≤ 3.5;

[0032] Silicic acidity is expressed as K. When 1.5≤K<1.8, ω As ≤2.5wt%; when 1.8≤K<2.0,ω As ≤3.5wt%. When 2.0≤K≤2.5, ω As ≤5wt%;

[0033] The upper limit of each of the other heavy metals (such as Cu, Pb, Zn, Mn, etc.) that need to be tested for leaching toxicity except Ni is ω Me =(3.26K-4.08)wt%, where K = 1.5-2.5, and the upper limit of Ni content in slag is (0.2-0.25)·ω Me ; Since Cu, Ni, Pb, Zn, Mn, etc. have high recovery, when K≥1.5, the upper limit values ​​of Cu, Pb, Zn, and Mn all reach more than 0.8wt%. For example, copper can generally be recovered through ore dressing. The arsenic-containing hazardous solid wastes that need to be treated are mainly arsenic-containing slags such as iron arsenate and calcium arsenate produced by precipitated arsenic after the recovery of valuable metals. Although it will not cause excessive heavy metals under normal circumstances, it is not ruled out that there are some special arsenic-containing materials, so a little attention is still needed during the batching process.

[0034] The silica acidity originally refers to the total number of moles of oxygen in the acidic oxides / the total number of moles of oxygen in the basic oxides. In this scheme, the following corrections are made: the aluminum oxide and chromium oxide in the slag are not included in the calculation of the silica acidity, and the ferric oxide is calculated as ferrous oxide;

[0035] The oxygen-silicon ratio originally refers to the molar number of oxygen in the slag / the molar number of silicon in the slag. In this scheme, the following corrections are made: the oxygen in the alumina in the slag is not taken into account, and As is calculated on an equal molar basis with silicon, that is, the oxygen-silicon ratio refers to the molar number of oxygen in the slag / the sum of the molar numbers of silicon and arsenic in the slag;

[0036] (2) The pre-mixed slag is smelted, and after being fully melted, it is rapidly cooled to obtain rapidly cooled slag.

[0037] The inventors found that the upper limit of arsenic content in the vitrified product will change with the changes in the proportion of the components of the compatible slag type, silica acidity, oxygen-silicon ratio, and Fe(III) / ∑Fe. max % is positively correlated, and the oxygen-silicon ratio is positively correlated with ω max % is negatively correlated. The vitrification method for arsenic-containing hazardous solid waste provided in the embodiment of the present application adjusts the silica acidity, oxygen-silicon ratio and the ratio of trivalent iron to total iron content so that these conditions are within a suitable range. On this premise, the upper limit content of arsenic and other heavy metals is studied. In the process of vitrification treatment of arsenic-containing hazardous solid waste, the chemical composition of the pre-mixed slag is controlled to meet the above requirements, which has a good treatment effect on arsenic-containing hazardous solid waste and can ensure that the treated vitrified slag meets GB / T 41015-2021 "Technical Requirements for Products of Solid Waste Vitrification Treatment". The method provided in this application has better treatment effect than the existing treatment method that only requires the arsenic content.

[0038] Specifically, the vitrification treatment method of arsenic-containing hazardous solid waste comprises the following steps:

[0039] S1. Pre-treat arsenic-containing hazardous solid waste

[0040] Arsenic-containing hazardous solid wastes mainly come from the metallurgical, chemical and wastewater treatment industries. Arsenic exists mainly in the form of arsenates, oxides or arsenic sulfide slag, including but not limited to iron arsenate, calcium arsenate, sodium arsenate and arsenic oxide, etc. The mass percentage of arsenic in arsenic-containing wastes is ≤50%;

[0041] It should be noted that if the arsenic in the slag is in the form of arsenic sulfide, it is best to treat it to convert it into relatively stable arsenate.

[0042] The arsenic-containing hazardous solid waste is pretreated by drying, crushing, granulating, agglomerating and other processes to obtain arsenic-containing hazardous solid waste residue with a dry basis moisture content of ≤50wt% and a particle size of ≤2cm. The specific pretreatment process is currently a conventional operation and will not be described in detail here, as long as the arsenic-containing hazardous solid waste residue can meet the above requirements.

[0043] S2. Preparation of pre-mixed slag

[0044] The auxiliary vitrified oxides are mixed with arsenic-containing hazardous solid waste slag to prepare the pre-mixed slag. The auxiliary vitrified oxides are mainly some oxides used to adjust the chemical composition of arsenic-containing hazardous solid waste slag. The auxiliary vitrified oxides include but are not limited to quartz stone, limestone, iron oxide, etc. or other materials that can be added as silicon dioxide, calcium oxide, and iron oxide (it can also be hazardous solid waste whose main components are the above compounds, but the content of heavy metals in hazardous solid waste needs to be controlled when using it).

[0045] After the auxiliary vitrified oxide is added, the pre-mixed slag meets the following conditions:

[0046] The pre-mixed slag is CaO-FeO x -Al 2 O 3 -Me x O y -SiO 2 The slag is mainly composed of multiple systems, among which (FeO x +Al 2 O 3 ) content ≥ 20wt%, Fe(III) / ∑Fe ≥ 50%, silica acidity ≥ 1.5, oxygen-silicon ratio ≤ 3.5;

[0047] Silicic acidity is expressed as K. When 1.5≤K<1.8, ω As ≤2.5wt%; when 1.8≤K<2.0,ω As ≤3.5wt%. When 2.0≤K≤2.5, ω As ≤5wt%;

[0048] The upper limit of each heavy metal other than Ni that needs to be tested for leaching toxicity is ω Me =(3.26K-4.08)wt%, where K = 1.5-2.5, and the upper limit of Ni content in slag is (0.2-0.25)·ω Me ;

[0049] The silica acidity originally refers to the total number of moles of oxygen in the acidic oxides / the total number of moles of oxygen in the basic oxides. The following corrections are made in this scheme: the aluminum oxide and chromium oxide in the slag are not included in the calculation of silica acidity, and ferric oxide is calculated as ferrous oxide;

[0050] The oxygen-silicon ratio originally refers to the molar number of oxygen in the slag divided by the molar number of silicon in the slag. The following corrections are made in this scheme: the oxygen in the alumina in the slag is not taken into account, and As is calculated on an equal molar basis with silicon, that is, the oxygen-silicon ratio refers to the molar number of oxygen in the slag divided by the sum of the molar numbers of silicon and arsenic in the slag.

[0051] The above-mentioned ferric oxide is calculated as ferrous oxide, which means that in the calculation of Fe 2 O 3 When calculating the molar amount of oxygen in the slag, the original n(O)=1.5n(Fe) is directly calculated as n(O)=n(Fe). For example, if there is a total of 1 mol of Fe in a certain mass of slag, 2 O 3 The actual amount of oxygen should be 1.5 mol, but it is calculated as 1 mol here.

[0052] The rest of the correction process is also to calculate, deduct or perform corresponding conversions in accordance with the requirements in the instructions.

[0053] S3. Smelting

[0054] The pre-mixed slag and fuel are put into a metallurgical furnace for smelting, or put into a metallurgical molten pool for smelting.

[0055] The main function of fuel is to provide heat for smelting, and the amount added can meet the smelting requirements.

[0056] The smelting process uses external force to stir the melt to form a stirred molten pool to ensure that the slag is fully and evenly melted.

[0057] To further ensure sufficient melting, the melting temperature is 50-200°C higher than the hemispherical temperature of the pre-mixed slag (for example, the melting temperature is 50°C, 100°C, 150°C or 200°C higher than the pre-mixed slag), and stays at this melting temperature for at least 30 minutes to ensure sufficient melting.

[0058] The lower the melt viscosity, the more complete the melting. To ensure complete melting, the melt viscosity is controlled to be ≤2.0 Pa·s, preferably ≤1.0 Pa·s.

[0059] Furthermore, the smelting atmosphere is an oxidizing atmosphere, such as oxygen, or a mixture of oxygen and other inert gases, where the inert gas refers to a gas that does not react with the melt (such as carbon dioxide).

[0060] S4, rapid cooling treatment

[0061] The melt is subjected to rapid cooling treatment, and the rapid cooling method includes water quenching, rapid air cooling or spray cooling. The rapid cooling method is preferably water quenching.

[0062] After rapid cooling, the vitrification degree of the pre-mixed slag is ≥85%.

[0063] After the rapid cooling treatment, the composition of the quenching slag is analyzed in accordance with GB / T 41015-2021 "Technical Requirements for Products of Solid Waste Vitrification Treatment". If the indicators are unqualified, the quenching slag is treated as arsenic-containing hazardous solid waste slag for ingredient correction and steps S2 to S4 are repeated.

[0064] After the chemical composition is prepared in step S2, the vitrified slag obtained by rapid cooling can basically meet the GB / T41015-2021 "Technical Requirements for Products of Solid Waste Vitrification Treatment". However, it is not ruled out that the vitrified slag does not meet the corresponding indicators due to errors in the treatment process. Therefore, if this happens, repeat steps S2 to S4.

[0065] In this step, the degree of vitrification, acid solubility loss rate, acid leaching method and water leaching method are all implemented in accordance with the requirements of GB / T41015-2021 national standard, and the relevant indicators are also implemented in accordance with GB / T 41015-2021 national standard.

[0066] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0067] Example 1

[0068] This embodiment provides a method for vitrification treatment of arsenic-containing hazardous solid waste.

[0069] The arsenic-containing hazardous solid waste provided in this embodiment is solid arsenic slag containing ferric arsenate, and its chemical composition is: 12.5wt% arsenic, 37.3wt% iron, and trace amounts of heavy metals.

[0070] (1) Drying and crushing the arsenic-containing hazardous solid waste to obtain arsenic-containing hazardous solid waste residue with a dry basis moisture content of ≤50wt% and a particle size of ≤2cm.

[0071] (2) The auxiliary vitrified oxides of iron oxide, silicon dioxide, aluminum oxide and calcium oxide are mixed with arsenic-containing hazardous solid waste slag, and the chemical composition is adjusted to obtain pre-mixed slag. The pre-mixed slag type has a silica acidity of 1.5 after correction, and the oxygen-silicon ratio after correction meets the requirements, wherein the pre-mixed slag Al 2 O 3 , Fe 2 O 3 , CaO, and arsenic contents are 10wt%, 17.1wt%, 20.8wt%, and 2.1wt%, respectively;

[0072] (FeO x +Al 2 O 3 ) has a content of about 30wt%;

[0073] Fe(III) / ∑Fe is about 100%;

[0074] Cu, Pb, Zn and Mn are all trace amounts, meeting the requirements.

[0075] (3) The pre-mixed slag is melted, the hemispherical temperature of the pre-mixed slag is less than 1250°C, and the melting temperature is controlled to be 1300°C during the melting process. The smelting is carried out at this temperature for 120 minutes. The viscosity of the melt meets the requirements and the fluidity is good.

[0076] (4) The melt obtained in the previous step is water quenched to obtain vitrified slag, and various indicators of the vitrified slag are tested according to the requirements of the national standard GB / T41015-2021: the vitrification degree of the molten slag is 95.6%, the acid solubility loss rate is less than 1%, and the acid leaching index and the water leaching index are both qualified.

[0077] Example 2

[0078] This embodiment provides a method for vitrification treatment of arsenic-containing hazardous solid waste.

[0079] The arsenic-containing hazardous solid waste provided in this embodiment is solid arsenic slag containing ferric arsenate, and its chemical composition is: 12.5wt% arsenic, 37.3wt% iron, and trace amounts of heavy metals.

[0080] (1) Drying and crushing the arsenic-containing hazardous solid waste to obtain arsenic-containing hazardous solid waste residue with a dry basis moisture content of ≤50wt% and a particle size of ≤2cm.

[0081] (2) The auxiliary vitrified oxides of iron oxide, silicon dioxide, aluminum oxide and calcium oxide are mixed with arsenic-containing hazardous solid waste slag, and the chemical composition is adjusted to obtain pre-mixed slag. The pre-mixed slag type has a silica acidity of 1.8 after correction, and an oxygen-silicon ratio of about 3.23 after correction, which meets the requirements. The pre-mixed slag Al 2 O 3 , Fe 2 O 3 , CaO, and arsenic contents are 5wt%, 24.1wt%, 25.3wt%, and 3.0wt%, respectively;

[0082] (FeO x +Al 2 O 3 ) content is about 29.1wt%;

[0083] Fe(III) / ∑Fe is about 100%;

[0084] Cu, Pb, Zn and Mn are all trace amounts, meeting the requirements.

[0085] (3) The pre-mixed slag is melted, the hemispherical temperature of the pre-mixed slag is 1260°C, and the melting temperature is controlled to be 1320°C during the melting process. The smelting is carried out at this temperature for 120 minutes. The viscosity of the melt meets the requirements and the fluidity is good.

[0086] (4) The melt obtained in the previous step is water quenched to obtain vitrified slag, and various indicators of the vitrified slag are tested according to the requirements of the national standard GB / T41015-2021: the vitrification degree of the molten slag is 96.3%, the acid solubility loss rate is less than 1%, and the acid leaching index and the water leaching index are both qualified.

[0087] Example 3

[0088] This embodiment provides a method for vitrification treatment of arsenic-containing hazardous solid waste.

[0089] The arsenic-containing hazardous solid waste provided in this embodiment is solid arsenic slag containing ferric arsenate, and its chemical composition is: 12.5wt% arsenic, 37.3wt% iron, and trace amounts of heavy metals.

[0090] (1) Drying and crushing the arsenic-containing hazardous solid waste to obtain arsenic-containing hazardous solid waste residue with a dry basis moisture content of ≤50wt% and a particle size of ≤2cm.

[0091] (2) The auxiliary vitrified oxides of iron oxide, silicon dioxide, aluminum oxide and calcium oxide are mixed with arsenic-containing hazardous solid waste slag, and the chemical composition is adjusted to obtain pre-mixed slag. The pre-mixed slag type has a silica acidity of 2.0 after correction, and the oxygen-silicon ratio after correction is about 3.07, which meets the requirements. The pre-mixed slag Al 2 O 3 , Fe 2 O 3 , CaO, and arsenic contents are 5wt%, 22.45wt%, 23.57wt%, and 4.2wt%, respectively;

[0092] (FeO x +Al 2 O 3 ) content is about 27.45wt%;

[0093] Fe(III) / ∑Fe is about 100%;

[0094] Cu, Pb, Zn and Mn are all trace amounts, meeting the requirements.

[0095] (3) The pre-mixed slag is melted, the hemispherical temperature of the pre-mixed slag is 1220°C, and the melting temperature is controlled to be 1280°C during the melting process. The smelting is carried out at this temperature for 120 minutes. The viscosity of the melt meets the requirements and the fluidity is good.

[0096] (4) The melt obtained in the previous step is water quenched to obtain vitrified slag, and various indicators of the vitrified slag are tested according to the requirements of the national standard GB / T41015-2021: the vitrification degree of the molten slag is 97.5%, the acid solubility loss rate is less than 1%, and the acid leaching index and the water leaching index are both qualified.

[0097] Example 4

[0098] This embodiment provides a method for vitrification treatment of arsenic-containing hazardous solid waste.

[0099] The arsenic-containing hazardous solid waste provided in this embodiment is solid arsenic slag containing ferric arsenate, and its chemical composition is: 12.5wt% arsenic, 37.3wt% iron, and trace amounts of heavy metals.

[0100] (1) Drying and crushing the arsenic-containing hazardous solid waste to obtain arsenic-containing hazardous solid waste residue with a dry basis moisture content of ≤50wt% and a particle size of ≤2cm.

[0101] (2) The auxiliary vitrified oxides of iron oxide, silicon dioxide, aluminum oxide and calcium oxide are mixed with arsenic-containing hazardous solid waste slag, and the chemical composition is adjusted to obtain pre-mixed slag. The pre-mixed slag type has a silica acidity of 2.5 after correction, and the oxygen-silicon ratio after correction is about 2.85, which meets the requirements. The pre-mixed slag Al 2 O 3 , Fe 2 O 3, CaO, and arsenic contents are approximately 5wt%, 19.83wt%, 20.82wt%, and 4.8wt%, respectively;

[0102] (FeO x +Al 2 O 3 ) content is about 24.83wt%;

[0103] Fe(III) / ∑Fe is about 100%;

[0104] Cu, Pb, Zn and Mn are all trace amounts, meeting the requirements.

[0105] (3) The pre-mixed slag is melted, the hemispherical temperature of the pre-mixed slag is 1252°C, and the melting temperature is controlled to be 1330°C during the melting process. The smelting is carried out at this temperature for 120 minutes. The viscosity of the melt meets the requirements and the fluidity is good.

[0106] (4) The melt obtained in the previous step is water quenched to obtain vitrified slag, and various indicators of the vitrified slag are tested according to the requirements of the national standard GB / T41015-2021: the vitrification degree of the molten slag is 97.7%, the acid solubility loss rate is less than 1%, and the acid leaching index and the water leaching index are both qualified.

[0107] Example 5

[0108] This embodiment provides a method for vitrification treatment of arsenic-containing hazardous solid waste.

[0109] The arsenic-containing hazardous solid waste provided in this embodiment is solid arsenic slag containing ferric arsenate, and its chemical composition is: 12.5wt% arsenic, 37.3wt% iron, and trace amounts of heavy metals.

[0110] (1) Drying and crushing the arsenic-containing hazardous solid waste to obtain arsenic-containing hazardous solid waste residue with a dry basis moisture content of ≤50wt% and a particle size of ≤2cm.

[0111] (2) The auxiliary vitrified oxides of iron oxide, silicon dioxide, aluminum oxide and calcium oxide are mixed with arsenic-containing hazardous solid waste slag, and the chemical composition is adjusted to obtain pre-mixed slag. The pre-mixed slag type has a silica acidity of 1.65 after correction, and an oxygen-silicon ratio of about 3.36 after correction, which meets the requirements. The pre-mixed slag Al 2 O 3 , Fe 2 O 3 , CaO, and arsenic contents are approximately 5wt%, 25.3wt%, 26.55wt%, and 2.48wt%, respectively;

[0112] (FeO x +Al 2 O 3 ) content is about 30.3wt%;

[0113] Fe(III) / ∑Fe is about 100%;

[0114] Cu, Pb, Zn and Mn are all trace amounts, meeting the requirements.

[0115] (3) The pre-mixed slag is melted, and the hemispherical temperature of the pre-mixed slag is about 1250°C. The melting temperature is controlled to be 1310°C during the melting process. The melting is carried out at this temperature for 120 minutes. The viscosity of the melt meets the requirements and the fluidity is good.

[0116] (4) The melt obtained in the previous step is water quenched to obtain vitrified slag, and various indicators of the vitrified slag are tested according to the requirements of the national standard GB / T41015-2021: the vitrification degree of the molten slag is 97.7%, the acid solubility loss rate is less than 1%, and the acid leaching index and the water leaching index are both qualified.

[0117] Example 6

[0118] This embodiment provides a method for vitrification treatment of arsenic-containing hazardous solid waste.

[0119] The arsenic-containing hazardous solid waste provided in this embodiment is solid arsenic slag containing calcium arsenate, and its chemical composition is: 21.42wt% arsenic, 34.29wt% calcium, and trace amounts of heavy metals.

[0120] (1) Drying and crushing the arsenic-containing hazardous solid waste to obtain arsenic-containing hazardous solid waste residue with a dry basis moisture content of ≤50wt% and a particle size of ≤2cm.

[0121] (2) The auxiliary vitrified oxides of iron oxide, silicon dioxide, aluminum oxide and calcium oxide are mixed with arsenic-containing hazardous solid waste slag, and the chemical composition is adjusted to obtain pre-mixed slag. The pre-mixed slag type has a silica acidity of 1.9 after correction, and an oxygen-silicon ratio of about 3.15 after correction, which meets the requirements. The pre-mixed slag Al 2 O 3 , Fe 2 O 3 , CaO, and arsenic contents are 5wt%, 23.31wt%, 24.48wt%, and 3.47wt%, respectively;

[0122] (FeO x +Al 2 O 3 ) content is about 28.31wt%;

[0123] Fe(III) / ∑Fe is about 100%;

[0124] Cu, Pb, Zn and Mn are all trace amounts, meeting the requirements.

[0125] (3) The pre-mixed slag is melted. The hemispherical temperature of the pre-mixed slag is about 1240°C. The melting temperature is controlled to be 1310°C during the melting process. The smelting is carried out at this temperature for 120 minutes. The viscosity of the melt meets the requirements and the fluidity is good.

[0126] (4) The melt obtained in the previous step is water quenched to obtain vitrified slag, and various indicators of the vitrified slag are tested according to the requirements of the national standard GB / T41015-2021: the vitrification degree of the molten slag is 97.2%, the acid solubility loss rate is less than 1%, and the acid leaching index and the water leaching index are both qualified.

[0127] Comparative Example 1

[0128] This comparative example provides a vitrification treatment method for arsenic-containing hazardous solid waste.

[0129] The arsenic-containing hazardous solid waste provided in this embodiment is solid arsenic slag containing calcium arsenate, and its chemical composition is: 21.42wt% arsenic, 34.29wt% calcium, and trace amounts of heavy metals.

[0130] (1) Drying and crushing the arsenic-containing hazardous solid waste to obtain arsenic-containing hazardous solid waste residue with a dry basis moisture content of ≤50wt% and a particle size of ≤2cm.

[0131] (2) The auxiliary vitrified oxide copper smelting slag (containing 2.5 wt% copper, mainly ferrous silicate) is decomposed into the following oxide compositions: Fe 2 O 3 About 9.75wt%, FeO about 50.62wt%, SiO 2 About 25.64wt%, Al 2 O 3 About 4.25wt%, CaO about 3.5wt%, the rest in small amounts), iron oxide, silicon dioxide, aluminum oxide and calcium oxide are mixed with arsenic-containing hazardous solid waste slag, and the chemical composition is adjusted to obtain pre-matched slag. The pre-matched slag type has a silica acidity of 1.9 after correction, and an oxygen-silicon ratio of about 3.19 after correction, which meets the requirements. The pre-matched slag Al 2 O 3 ,FeO,Fe 2 O 3 , CaO, and arsenic contents are 5%, 12.88wt%, 7.02wt%, 25.61wt%, and 3.47wt%, respectively;

[0132] (FeO x +Al 2 O 3 ) content is about 26.33wt%;

[0133] Fe(III) / ∑Fe is about 32.9%;

[0134] Cu, Pb, Zn and Mn are all trace amounts, meeting the requirements.

[0135] (3) The pre-mixed slag is melted. The hemispherical temperature of the pre-mixed slag is about 1240°C. The melting temperature is controlled to be 1310°C during the melting process. The smelting is carried out at this temperature for 120 minutes. The viscosity of the melt meets the requirements and the fluidity is good.

[0136] (4) The melt obtained in the previous step is water quenched to obtain vitrified slag, and various indicators of the vitrified slag are tested according to the requirements of GB / T 41015-2021 national standard: the degree of vitrification of the molten slag is 97.2%, the acid solubility loss rate is less than 1%, and the acid leaching result shows that As exceeds the standard.

[0137] This comparative example is used to verify the importance of the Fe(Ⅲ) / ∑Fe ratio requirement. When Fe(Ⅲ) / ∑Fe does not meet ≥50%, the results show that the acid leaching arsenic exceeds the standard. Since the batching test is a very complicated process, it is impossible to achieve a true single factor variable without affecting other parameter values. This comparative example verifies the importance of the Fe(Ⅲ) / ∑Fe ratio requirement while keeping the fluctuation values ​​of other parameters as small as possible.

[0138] Comparative Example 2

[0139] This comparative example provides a vitrification treatment method for arsenic-containing hazardous solid waste.

[0140] The arsenic-containing hazardous solid waste provided in this embodiment is solid arsenic slag containing calcium arsenate, and its chemical composition is: 21.42wt% arsenic, 34.29wt% calcium, and trace amounts of heavy metals.

[0141] (1) Drying and crushing the arsenic-containing hazardous solid waste to obtain arsenic-containing hazardous solid waste residue with a dry basis moisture content of ≤50wt% and a particle size of ≤2cm.

[0142] (2) The auxiliary vitrified oxides of iron oxide, silicon dioxide, aluminum oxide and calcium oxide are mixed with arsenic-containing hazardous solid waste slag, and the chemical composition is adjusted to obtain pre-mixed slag. The pre-mixed slag type has a silica acidity of 1.9 after correction, and an oxygen-silicon ratio of about 3.15 after correction, which meets the requirements. The pre-mixed slag Al 2 O 3 , Fe 2 O 3 , CaO, and arsenic contents are 5wt%, 23.19wt%, 24.35wt%, and 3.75wt%, respectively;

[0143] (FeO x +Al 2 O 3 ) content is about 28.19wt%;

[0144] Fe(III) / ∑Fe is about 100%;

[0145] Cu, Pb, Zn and Mn are all trace amounts, meeting the requirements.

[0146] (3) The pre-mixed slag is melted. The hemispherical temperature of the pre-mixed slag is about 1240°C. The melting temperature is controlled to be 1310°C during the melting process. The smelting is carried out at this temperature for 120 minutes. The viscosity of the melt meets the requirements and the fluidity is good.

[0147] (4) The melt obtained in the previous step is water quenched to obtain vitrified slag, and various indicators of the vitrified slag are tested according to the requirements of GB / T41015-2021 national standard: the degree of vitrification of the molten slag is 97.2%, the acid solubility loss rate is less than 1%, and the acid leaching result shows that As exceeds the standard, which does not meet the vitrification treatment requirements.

[0148] This comparative example is used to verify the importance of the K value. The results show that the corresponding K value should not exceed the upper limit of compatibility. If the upper limit of the K value is exceeded, the acid leaching arsenic will exceed the standard.

[0149] Comparative Example 3

[0150] This embodiment provides a method for vitrification treatment of arsenic-containing hazardous solid waste.

[0151] The arsenic-containing hazardous solid waste provided in this embodiment is arsenic-containing zinc oxide smoke ash, and its chemical composition is: 21.42wt% arsenic, 45.29wt% zinc, and other heavy metal contents are less than 1wt%.

[0152] (1) Drying and crushing the arsenic-containing hazardous solid waste to obtain arsenic-containing hazardous solid waste residue with a dry basis moisture content of ≤50wt% and a particle size of ≤2cm.

[0153] (2) The auxiliary vitrified oxides of iron oxide, silicon dioxide, aluminum oxide and calcium oxide are mixed with arsenic-containing hazardous solid waste slag, and the chemical composition is adjusted to obtain pre-mixed slag. The pre-mixed slag type has a silica acidity of 1.9 after correction, and an oxygen-silicon ratio of about 3.29 after correction, which meets the requirements. The pre-mixed slag Al 2 O 3 , Fe 2 O 3 , CaO, and arsenic contents are 5wt%, 22.63wt%, 23.75wt%, and 2.1wt%, respectively;

[0154] (FeO x +Al 2 O 3 ) content is about 27.63wt%;

[0155] Fe(III) / ∑Fe is about 100%;

[0156] Cu, Pb and Mn are all in trace amounts, meeting the requirements, and the Zn content is 4.44wt%, exceeding the upper limit.

[0157] (3) The pre-mixed slag is melted. The hemispherical temperature of the pre-mixed slag is about 1240°C. The melting temperature is controlled to be 1310°C during the melting process. The smelting is carried out at this temperature for 120 minutes. The viscosity of the melt meets the requirements and the fluidity is good.

[0158] (4) The melt obtained in the previous step is water quenched to obtain vitrified slag, and various indicators of the vitrified slag are tested according to the national standard GB / T41015-2021: the vitrification degree of the molten slag is 97.2%, the acid solubility loss rate is less than 1%, and the acid leaching result shows that Zn exceeds the standard, which does not meet the vitrification treatment requirements.

[0159] This comparative example is used to verify the importance of the heavy metal ratio range. The results show that the heavy metal (Zn) content exceeds the standard and does not meet the requirements of vitrification after treatment. However, in general, the arsenic-containing zinc oxide smoke ash used in this comparative example has a high recycling value due to its high zinc content and is not directly treated as hazardous waste.

[0160] Comparative Example 4

[0161] This embodiment provides a method for vitrification treatment of arsenic-containing hazardous solid waste.

[0162] The arsenic-containing hazardous solid waste provided in this embodiment is solid arsenic slag containing calcium arsenate, and its chemical composition is: 21.42wt% arsenic, 34.29wt% calcium, and trace amounts of heavy metals.

[0163] (1) Drying and crushing the arsenic-containing hazardous solid waste to obtain arsenic-containing hazardous solid waste residue with a dry basis moisture content of ≤50wt% and a particle size of ≤2cm.

[0164] (2) The auxiliary vitrified oxides of iron oxide, silicon dioxide, aluminum oxide and calcium oxide are mixed with arsenic-containing hazardous solid waste slag, and the chemical composition is adjusted to obtain pre-mixed slag. The pre-mixed slag type has a silica acidity of 3.0 after correction, and an oxygen-silicon ratio of about 2.73 after correction, which meets the requirements. The pre-mixed slag Al 2 O 3 , Fe 2 O 3 , CaO, and arsenic contents are 5wt%, 18.37wt%, 19.28wt%, and 3.75wt%, respectively;

[0165] (FeO x +Al 2 O 3 ) content is about 23.37wt%;

[0166] Fe(III) / ∑Fe is about 100%;

[0167] Cu, Pb, Zn and Mn are all trace amounts, meeting the requirements.

[0168] (3) The pre-mixed slag is melted. The hemispherical temperature of the pre-mixed slag is about 1320°C. The melting temperature is controlled at 1380°C during the melting process. The melting is performed at this temperature for 120 minutes. The viscosity of the melt is too high, the fluidity is extremely poor, and it is difficult to operate.

[0169] (4) The melt obtained in the previous step is water quenched to obtain vitrified slag, and various indicators of the vitrified slag are tested according to the national standard GB / T41015-2021: the vitrification degree of the molten slag is 98.2%, the acid solubility loss rate is less than 1%, and the acid leaching result meets the requirements.

[0170] This comparative example is used to verify the importance of K value being within an appropriate range. If K value is too large, the melt viscosity is too large, the fluidity is extremely poor, and it is difficult to operate.

[0171] In summary, the vitrification treatment method for arsenic-containing hazardous solid waste provided in the embodiment of the present application regulates the silica acidity, oxygen-silicon ratio and the ratio of trivalent iron to total iron content so that these conditions are within a suitable range. On this premise, the upper limit content of arsenic and other heavy metals is studied. In the process of vitrification treatment of arsenic-containing hazardous solid waste, the chemical composition of the pre-mixed slag is controlled to meet the above requirements, which has a good treatment effect on arsenic-containing hazardous solid waste and can ensure that the treated vitrified slag meets GB / T41015-2021 "Technical Requirements for Solid Waste Vitrification Products". The method provided in this application has a better treatment effect than the existing treatment method that only requires the arsenic content.

[0172] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A vitrification treatment method for arsenic-containing hazardous solid waste, It is characterized in that include: (1) The auxiliary vitrified material is mixed with arsenic-containing hazardous solid waste to prepare a pre-mixed slag, wherein the pre-mixed slag meets the following conditions: The pre-mixed slag is CaO-FeO x -Al 2 O 3 -Me x O y -SiO 2 The slag is mainly composed of multiple systems, among which (FeO x +Al 2 O 3 ) content ≥ 20wt%, Fe(III) / ∑Fe ≥ 50%, silica acidity ≥ 1.5, oxygen-silicon ratio ≤ 3.5; The silica acidity is expressed as K. When 1.5≤K<1.8, ω As ≤2.5wt%; when 1.8≤K<2.0,ω As ≤3.5wt%; when 2.0≤K≤2.5,ω As ≤5wt%; The upper limit of each heavy metal that needs to be tested for leaching toxicity except Ni is ω Me =(3.26K-4.08)wt%, where K = 1.5-2.5, and the upper limit of Ni content in slag is (0.2-0.25)·ω Me ; The silica acidity refers to the total number of moles of oxygen in the acidic oxides / the total number of moles of oxygen in the basic oxides. Alumina and chromium oxide in the slag are not included in the calculation of silica acidity, and ferric oxide is calculated as ferrous oxide. The oxygen-silicon ratio refers to the molar number of oxygen in the slag / the sum of the molar numbers of silicon and arsenic in the slag. The oxygen in the alumina in the slag is not included in the calculation of the oxygen-silicon ratio. (2) Smelting the pre-mixed slag, and then rapidly cooling it after it is fully melted to obtain rapidly cooled slag.

2. The vitrification treatment method for arsenic-containing hazardous solid waste according to claim 1, It is characterized in that The smelting temperature is 50-200° C. higher than the hemispherical temperature of the pre-mixed slag, and the smelting temperature is maintained for at least 30 minutes.

3. The vitrification treatment method for arsenic-containing hazardous solid waste according to claim 2, It is characterized in that The melt viscosity was controlled to be ≤2.0 Pa·s.

4. The vitrification treatment method for arsenic-containing hazardous solid waste according to claim 3, It is characterized in that Control the melt viscosity to ≤1.0 Pa·s.

5. The vitrification treatment method for arsenic-containing hazardous solid waste according to claim 1, It is characterized in that After rapid cooling, the vitrification degree of the pre-mixed slag is ≥85%.

6. The vitrification treatment method for arsenic-containing hazardous solid waste according to claim 5, It is characterized in that The rapid cooling methods include water quenching, rapid air cooling or spray cooling.

7. The vitrification treatment method for arsenic-containing hazardous solid waste according to claim 1, It is characterized in that The auxiliary vitrified material includes at least one of silicon dioxide, calcium oxide, iron oxide and aluminum oxide, or hazardous solid waste mainly composed of the above oxides.

8. The vitrification treatment method for arsenic-containing hazardous solid waste according to claim 1, It is characterized in that The melting atmosphere is an oxidizing atmosphere.

9. The vitrification treatment method for arsenic-containing hazardous solid waste according to claim 1, It is characterized in that After obtaining the quenched slag, the method further comprises: (3) The composition of the quenched slag is analyzed and tested in accordance with GB / T 41015-2021 "Technical Requirements for Products of Solid Waste Vitrification Treatment". If the indicators are unqualified, the quenched slag is treated as arsenic-containing hazardous solid waste slag for ingredient correction and steps (1) to (3) are repeated.