A method for waste disposal

Abstract

This application discloses a waste treatment method that utilizes carbide slag and sludge as raw materials to produce hydrogen at 400℃-600℃. This method not only achieves resource utilization of sludge and carbide slag, significantly reducing the potential environmental risks posed by sludge and carbide slag accumulation and discharge, but also leverages the core mechanism that cellulose-based organic matter at 400℃-600℃ tends to produce CO2 and H2 as major byproducts, and the reaction of CO2 with Ca in carbide slag under high-temperature steam conditions to generate CaCO3, thereby maximizing H2 collection. This invention has significant practical implications for the resource utilization of carbide slag and sludge, two major solid wastes. Furthermore, the hydrogen production process at 400℃-600℃ enables negative CO2 emissions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid waste harmless treatment, in particular to a waste treatment method. BACKGROUND

[0002] With the rapid development of economy, the scale of municipal sewage treatment in China is also increasing day by day, and the sludge output generated by the operation of sewage treatment plants is also increasing year by year. According to statistics, the municipal sludge output in China in 2019 reached 6000 tons (calculated at 80% moisture content). By 2025, the municipal sludge output in China will exceed 90 million tons. Influenced by the long-term "pay more attention to water and less attention to sludge" concept in China, the treatment of municipal sludge has not been given enough attention, resulting in an increasing amount of municipal sludge in major cities in China, which seriously affects the normal operation of sewage treatment plants, and the problem of sludge treatment and disposal has not been effectively solved. Overall, the municipal sludge treatment and disposal technology in China has formed four process routes mainly including "deep dewatering + emergency landfill", "anaerobic digestion + land use", "aerobic fermentation + land use", and "dry incineration + ash landfill / building material utilization". The building material utilization process will emit a large amount of CO2, which does not meet the current low-carbon environmental protection policy in China. Emergency landfill is simple to operate, but this method will waste resources and increase environmental risks. Land use is better than incineration, but it requires stable treatment of sludge, which is a short board of sludge treatment and disposal at present in China. At the same time, due to the mixing of industrial wastewater, the heavy metals and other toxic and harmful substances in municipal sludge often exceed the standard, which limits the land use.

[0003] Calcium carbide slag is the main by-product of the calcium carbide method of acetylene process. Due to the rapid development of industries such as polyvinyl chloride, the production of calcium carbide slag has increased sharply. Generally, the production of 1 t of polyvinyl chloride can produce about 1.2-1.5 t of calcium carbide slag, and the annual output of calcium carbide slag in China is about 200 million tons. The main component of calcium carbide slag is Ca(OH)2, which is CaO after drying and dewatering, with a calcium mass fraction of about 60%-70%, and the slurry has strong alkalinity, in addition to a small amount of Al2O3 and SiO2 impurities. Due to its strong alkalinity, calcium carbide slag can cause various environmental problems such as soil and water sources, and harm human health. There are many ways to utilize calcium carbide slag, which can be used as a main raw material for cement, or as a chemical product, but the effect is not satisfactory, and the carbon emission is high, which does not meet the "double carbon" policy in China.

[0004] The traditional treatment and disposal process of market sludge, sludge generated in the sewage treatment process and calcium carbide slag has the disadvantages of high process energy consumption, high equipment cost, inability to realize resource utilization of sludge and calcium carbide slag at the same time, and inability to produce hydrogen, and there is no perfect alternative solution. Therefore, it is urgent to solve the problem of large storage of municipal sludge, sludge generated in the sewage treatment process and calcium carbide slag in China. SUMMARY

[0005] The application discloses a waste treatment method to solve the problem of large storage of municipal sludge, sludge generated in the sewage treatment process and carbide slag in China.

[0006] To achieve the above-mentioned purpose, the embodiments of the present application adopt the following technical solutions:

[0007] The application provides a waste treatment method, which comprises the following steps: uniformly mixing sludge and carbide slag, adding a catalyst, and heating to carry out a hydrogen production reaction, so as to realize waste treatment, wherein the catalyst is a multi-core coordination compound, and the multi-core coordination compound is obtained by combining a core body with a ligand containing a hydroxyl group.

[0008] Optionally, the sludge comprises C, N, H, O and S elements, and the content of the C, N, H, O and S elements in the sludge accounts for 42.5-52.5%, 5.7-6.9%, 6.2-6.5%, 5.4-8.3% and 3.2-4.7% respectively.

[0009] Optionally, the carbide slag comprises Ca(OH)2, and the mass fraction of Ca in the carbide slag is 60%-70%.

[0010] Optionally, the mass ratio of the sludge to the carbide slag after drying is 2:1-5:1.

[0011] Optionally, the heating temperature is 400-600 DEG C.

[0012] Optionally, the addition amount of the catalyst is 3%-7% of the total mass of the mixed sludge and carbide slag.

[0013] Optionally, the core body in the catalyst is two or more of an aluminum core, a silicon core, a nickel core and a calcium core.

[0014] Optionally, the catalyst is a multi-core with aluminum, silicon, nickel and calcium as the core body, and a ligand containing a hydroxyl group is combined to obtain a multi-core coordination compound, wherein the mass fraction of the aluminum, silicon, nickel and calcium elements in the multi-core accounts for 5-20 parts, 3-15 parts, 30-55 parts and 6-10 parts respectively.

[0015] Optionally, the carbide slag is crushed before the sludge and the carbide slag are uniformly mixed.

[0016] Optionally, the sludge and the carbide slag are mixed and then heated, and the heating temperature is 400-600 DEG C.

[0017] The above at least one technical solution adopted by the embodiments of the present application can achieve the following beneficial effects: the present application provides a waste treatment method, which produces hydrogen by using carbide slag and sludge as raw materials at 400-600 DEG C. Not only is the resource utilization of sludge and carbide slag realized, but also the potential risks of sludge and carbide slag accumulation and external discharge to the environment are greatly reduced. In addition, based on the core mechanism that cellulose-based organic matter tends to generate CO2 and H2 as main by-products at 400-600 DEG C, and the reaction of CO2 and Ca in carbide slag under high-temperature steam conditions to generate CaCO3, H2 can be collected to the maximum extent. The present application has important practical significance for the resource utilization of two major solid wastes, i.e. carbide slag and sludge. In addition, CO2 can be discharged by producing hydrogen at 400-600 DEG C. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the embodiments of the present application and, together with the description, further serve to explain the principles of the present application and to enable a person skilled in the relevant art to make and use the present application. In the drawings:

[0019] Figure 1 A flow chart of the process of producing hydrogen by using carbide slag and sludge as raw materials at 400-600 DEG C in the embodiments of the present application.

[0020] Figure 2 A graph of the types and proportions of hydrogen production products of municipal sludge and carbide slag in a sewage treatment plant in Beijing in Embodiment 1 of the present application, wherein the unit is %.

[0021] Figure 3 A graph of the types and proportions of hydrogen production products of secondary sedimentation tank sludge and carbide slag in a sewage treatment plant in Beijing in Embodiment 2 of the present application, wherein the unit is %. DETAILED DESCRIPTION

[0022] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described below in detail with reference to the embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person skilled in the art without creative work fall within the scope of protection of the present application.

[0023] According to one embodiment of the present application, a waste treatment method is provided, which comprises: uniformly mixing sludge and carbide slag, adding a catalyst, heating to produce hydrogen, and realizing waste treatment. The catalyst is a multi-core coordination compound, and the multi-core coordination compound is obtained by combining a core with a ligand containing a hydroxyl group.

[0024] The sludge refers to the sludge generated in the operation of a sewage treatment plant. In the embodiments of the present application, the source of the sludge can be anywhere, and no specific limitation is made. The carbide slag refers to the by-product generated in the process of producing acetylene by the calcium carbide method. The sludge contains C, N, H, O and S elements, and the content of C, N, H, O and S in the sludge accounts for 42.5-52.5%, 5.7-6.9%, 6.2-6.5%, 5.4-8.3%, and 3.2-4.7%, respectively. The carbide slag contains Ca(OH)2, and the mass fraction of Ca in the carbide slag is 60%-70%.

[0025] The specific treatment method can be: adding the sludge into the reactor, and adding the crushed carbide slag at the same time, wherein the mass fraction of the sludge is 80% in terms of water content, which is the general water content of the sludge, and the lower the water content, the better, because the mixture of the general sludge and the carbide slag needs to be dried, and then a catalyst is added for subsequent steps. In the embodiments of the present application, the sludge and the carbide slag can be mixed in any ratio. Preferably, the mass ratio of the dried sludge to the carbide slag is 2:1-5:1, for example, it can be 2:1, 3:1, 4:1, 5:1 or any value between the above values. More preferably, the mass ratio of the dried sludge to the carbide slag is 2:1, when the mass ratio of 2:1-5:1 is selected, especially when the mass ratio of 2:1 is selected, the content of Ca in the mixture of the sludge and the carbide slag meets the optimal reaction condition.

[0026] The reactor is placed in a stirrer to stir and mix the sludge and the carbide slag. The catalyst is added and continues to be stirred, and the amount of the catalyst is 3%-7% of the total mass of the mixture of the sludge and the carbide slag, for example, it can be 3%, 4%, 5%, 6%, 7% or any value between the above values. After mixing uniformly, the above mixture is heated to 400-600°C for hydrogen production reaction by using a heating furnace, wherein the heating temperature can be, for example, 400°C, 450°C, 500°C, 550°C, 600°C or any value between the above values. In the embodiments of the present application, the sludge and the carbide slag can be mixed in any ratio. Preferably, the amount of the catalyst is 3% of the mass of the mixture of the sludge and the carbide slag. With this ratio, the raw materials are easy to stir uniformly, and the uniformity of the reaction product is the highest.

[0027] The mixing of the sludge and the carbide slag is carried out by pre-mixing. In the embodiments of the present application, the carbide slag can be the waste slag generated in the direct acetylene method process, or the carbide slag can be crushed and used, and the present application does not make specific limitations on this. The mixing of the crushed carbide slag and the sludge can increase the reaction area of the carbide slag, increase the specific surface area and active sites after crushing, improve the reaction efficiency, and make the treatment effect of the carbide slag better.

[0028] The sludge has a water content of 80% by mass, so it contains a lot of water. After the sludge is mixed with the carbide slag, it is heated in a heating system, and the heating temperature is 400-600°C, which can create a water vapor atmosphere with the help of the water in the sludge, i.e., the source of water in the technical principle chemical equation. The heating temperature can be, for example, 400°C, 450°C, 500°C, 550°C, 600°C, or any value between the above values. The heated sludge and carbide slag are subjected to secondary mixing treatment, and a catalyst is added, and the subsequent reaction occurs in a high-efficiency stirring system. In the embodiments of the present application, the secondary mixing is because the sludge and the carbide slag will be agglomerated under the water vapor atmosphere of the sludge, and need to be stirred and mixed again for better reaction.

[0029] The existing sludge needs to be heated to above 1000°C to produce hydrogen, which requires a high temperature, while the present application can produce hydrogen at 400-600°C. The catalyst in the present application is a multi-core coordination compound, which is obtained by combining a core with a ligand containing a hydroxyl group. The catalyst can be arbitrarily selected. Preferably, the core in the catalyst is two or more of aluminum core, silicon core, nickel core, and calcium core. More preferably, the catalyst is a multi-core containing aluminum, silicon, nickel, and calcium as the core, and a ligand containing a hydroxyl group to obtain a multi-core coordination compound. The mass fraction of aluminum, silicon, nickel, and calcium in the multi-core is 5-20 parts, 3-15 parts, 30-55 parts, and 6-10 parts, respectively.

[0030] The sludge contains a large amount of cellulose material. When heated in the presence of a catalyst, as the temperature rises, the hydroxyl groups in the ligands of the catalyst oxidize the cellulose-based organic matter, promoting its gradual decomposition. Under the action of the hydroxyl-containing ligands, the cellulose-based organic matter first generates CO2 and CH4. The catalyst contains polynuclear atoms with aluminum, silicon, nickel, and calcium as cores. These polynuclear atoms have reducing properties, enabling CH4 reforming to generate CO2 and H2 under steam conditions. After the cellulose-based organic matter generates CH4, the catalyst promotes the reaction of CH4 at 400℃-600℃, tending towards the generation of CO2 and H2. Therefore, H2 can be produced through catalytic catalysis, achieving a green and low-carbon technology for waste treatment. CO2 is absorbed by Ca in the carbide slag to generate CaCO3, thus achieving efficient separation of H2 and CO2 and improving the purity of H2.

[0031] The primary function of the catalyst is to lower the reaction temperature of hydrogen production from sludge and carbide slag. Additionally, the catalyst can improve the degradation efficiency of organic matter in the sludge, ensuring a more complete reaction. The CO2 produced during the reaction of sludge and carbide slag can rapidly react with the large amount of free calcium in the carbide slag under heating conditions to generate CaCO3. This allows the reaction to proceed in the forward direction and increases the purity of H2 in the products.

[0032] In the embodiments of this specification, the heating temperature after adding the catalyst is 400℃-600℃. This invention is based on the fact that organic matter, mainly cellulose, tends to produce CO2 and H2 as major byproducts when reacting at 400℃-600℃; however, under high-temperature conditions, cellulose materials produce various coal tar and other major byproducts. Without the catalyst of this invention, at temperatures below 400℃, the main product of the thermal decomposition of cellulose materials is CH4, with CO2 as a byproduct; at temperatures below 600℃, the main product is CO2, with H2 and CO as byproducts; and at temperatures above 800℃, the main product is H2, with CO and various coal tar as byproducts. However, with the addition of the catalyst in this invention, hydrogen production can be achieved at 400℃-600℃.

[0033] The specific technical principles involved in the waste treatment method are as follows:

[0034] CH4 + H2O = 3H2 + CO

[0035] CO + H₂O = H₂ + CO₂

[0036] C6(H2O)5 + 7H2O = 12H2 + 6CO2

[0037] CO2 + carbide slag → CaCO3

[0038] This treatment method can produce hydrogen at a low temperature of 400℃-600℃, with high hydrogen production efficiency, reaching about 90% of the total products. CO2 emissions are low, only about 5% of the total products. This method can digest a large amount of organic matter in the sludge, simultaneously achieving resource recovery of electrolytic slag and sludge. The H2 produced can be used as a green energy source, meeting my country's requirements for low-carbon and green development.

[0039] The treatment method involves processing units including a mixing tank, a heating system, a feeding system, and a hydrogen production system. The mixing tank is used to mix sludge and carbide slag. The mixing tank includes a dosing device and a stirring device. The heating system is used to heat the mixed sludge and carbide slag. The feeding system is used to add a catalyst.

[0040] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0041] Example 1:

[0042] A method for treating waste is provided, comprising the following steps:

[0043] (1) Add municipal sludge from a wastewater treatment plant in Beijing to the reactor, and add crushed carbide slag at the same time. Place the reactor in a stirrer and stir for 60 minutes to mix the municipal sludge and carbide slag evenly. During the stirring process, the reactor is heated to 600°C. The mass ratio of the dried municipal sludge to the carbide slag is 5:1.

[0044] (2) Continue to mix the heated municipal sludge and carbide slag a second time, and add a multinuclear coordination compound catalyst. The amount of catalyst is 7% of the mass of the municipal sludge and carbide slag mixture. Continue stirring for 60 minutes. During the stirring process, the reactor is heated to 600°C to achieve waste treatment.

[0045] The catalyst is a polynuclear compound containing aluminum, silicon, nickel, and calcium as its core, which combines with a hydroxyl-containing ligand to form a polynuclear coordination compound. The mass percentages of aluminum, silicon, nickel, and calcium in the polynuclear compound are 20 parts, 15 parts, 55 parts, and 10 parts, respectively. The catalyst's main function in the heating process is to lower the reaction temperature of municipal sludge and carbide slag in the hydrogen production process. The main products generated during the reaction of municipal sludge and carbide slag at a wastewater treatment plant in Beijing are described. Figure 2 As shown in the figure. The types and proportions of hydrogen production products from municipal sludge and calcium carbide slag are as follows. Figure 2 As shown, Figure 2 The volume percentage of hydrogen is 92.3%, CH4 is 0.6%, CO is 1.9%, and CO2 is 5.2%. Figure 2It can be seen that hydrogen accounts for the majority of the products after waste treatment, indicating that the waste treatment method of this embodiment can produce hydrogen at 400-600°C.

[0046] The municipal sludge in this embodiment is provided by a sewage treatment plant in Beijing. The municipal sludge used in this embodiment is the sludge treated by the entire sewage process of the sewage treatment plant, including the primary sedimentation tank, the secondary sedimentation tank and the mixed sludge of the subsequent process. The content of C, N, H, O and S elements in the municipal sludge accounts for 52.5%, 5.7%, 6.5%, 5.4% and 4.7%, respectively.

[0047] The carbide slag in this embodiment is provided by a polyvinyl chloride processing plant. Its main component is Ca(OH)2, and after drying and dehydration, it is CaO, with a calcium mass fraction of 70%. The slurry of the carbide slag has strong alkalinity, and in addition, it also contains a small amount of Al2O3 and SiO2 impurities. In this embodiment, other types of carbide slag with Ca(OH)2 as the main component are also suitable for this application, and this embodiment does not make specific limitations.

[0048] Example 2:

[0049] A waste treatment method is provided, including the following steps:

[0050] (1) Add the secondary sedimentation tank sludge of a sewage treatment plant in Beijing and crushed carbide slag to the reactor, and stir for 60 min in the stirrer to mix the municipal sludge and carbide slag uniformly. The reactor is heated during the stirring process, and the heating temperature is 400°C. The mass ratio of the dried municipal sludge to the carbide slag is 2:1.

[0051] (2) Continue to mix and treat the heated municipal sludge and carbide slag, and add a catalyst, a multi-core coordination compound, at the same time. The amount of the catalyst is 3% of the mass of the mixture of the municipal sludge and the carbide slag, and continue to stir for 60 min. The reactor is heated during the stirring process, and the heating temperature is 400°C, to achieve the treatment of the waste.

[0052] The catalyst is a multi-core containing aluminum, silicon, nickel and calcium as the core, combined with a ligand containing hydroxyl to obtain a multi-core coordination compound. The mass fraction of aluminum, silicon, nickel and calcium elements in the multi-core accounts for 5 parts, 3 parts, 30 parts and 6 parts, respectively. The main role of the catalyst in the heating process is to reduce the hydrogen production reaction temperature of the municipal sludge and the carbide slag. Figure 3 The main products produced during the reaction of the municipal sludge and the carbide slag of a sewage treatment plant in Beijing are shown in the table. Figure 3 The types and proportions of hydrogen production products of the secondary sedimentation tank sludge and the carbide slag are shown in the table. Figure 3The volume ratio of hydrogen is 88.5%, the volume ratio of CH4 is 5.6%, the volume ratio of CO is 2.4%, and the volume ratio of CO2 is 3.5%, which is obtained from Figure 3 It can be seen that hydrogen accounts for the majority of the products after waste treatment, indicating that the waste treatment method of this embodiment can produce hydrogen at 400-600°C.

[0053] The proportions of C, N, H, O and S in the secondary sedimentation tank sludge are 43%, 6.7%, 5.4%, 7.1% and 3.6%, respectively. The main component of the carbide slag is Ca(OH)2, with a calcium mass fraction of about 68%, and also contains a small amount of Al2O3 and SiO2 impurities.

[0054] Example 3:

[0055] A waste treatment method is provided, comprising the steps of:

[0056] (1) Adding municipal sludge from a sewage treatment plant in Beijing and crushed carbide slag into a reactor, and stirring in a stirrer for 60 min to mix the municipal sludge and carbide slag uniformly, and heating the reactor during stirring, with a heating temperature of 500°C, wherein the mass ratio of the dried municipal sludge to the carbide slag is 4:1;

[0057] (2) Continuing to mix and treat the heated municipal sludge and carbide slag, and adding a catalyst, a multi-core coordination compound, with a catalyst amount of 5% of the mass of the mixture of municipal sludge and carbide slag, and continuing to stir for 60 min, and heating the reactor during stirring, with a heating temperature of 500°C, to achieve waste treatment.

[0058] The catalyst is a multi-core containing aluminum, silicon, nickel and calcium as the core, combined with a ligand containing a hydroxyl group to obtain a multi-core coordination compound, wherein the mass fraction of aluminum, silicon, nickel and calcium elements in the multi-core is 15 parts, 8 parts, 40 parts and 8 parts, respectively. The municipal sludge in this embodiment is provided by a sewage treatment plant in Beijing, and the municipal sludge used in this embodiment is the sludge treated by the entire sewage process of the sewage treatment plant, including the primary sedimentation tank, the secondary sedimentation tank and the mixed sludge of the subsequent processes. The content of C, N, H, O and S in the municipal sludge is 42.5%, 6.9%, 6.2%, 8.3% and 3.2%, respectively.

[0059] The carbide slag in this embodiment is provided by a polyvinyl chloride processing plant, and its main component is Ca(OH)2, which is CaO after drying and dehydration, with a calcium mass fraction of 65%. The slurry of the carbide slag has strong alkalinity, and also contains a small amount of Al2O3 and SiO2 impurities. In this embodiment, other types of carbide slag with Ca(OH)2 as the main component are also suitable for this application, which is not specifically limited in this embodiment.

[0060] The advantages and beneficial technical effects of the present application are as follows:

[0061] (1) The present application utilizes municipal sludge and carbide slag to produce hydrogen, which not only realizes the resource utilization of bulk solid waste, but also realizes low-temperature and high-efficiency hydrogen production.

[0062] (2) The present application can capture CO2 in the decomposition products of municipal sludge while producing hydrogen, which conforms to the "carbon peak" and "carbon emission reduction" policies of China, and ultimately converts CO2 into CaCO3 products for storage, realizing benefits.

[0063] (3) Based on the reaction characteristics of cellulose materials, which tend to generate CO2 and H2 as main by-products at low temperatures, and with the help of free calcium in carbide slag at 400-600 DEG C, the present application realizes efficient separation of CO2 and H2.

[0064] (4) The present application utilizes municipal sludge and carbide slag to produce hydrogen, and the utilization rate of municipal sludge and carbide slag is close to 100%, which has broad practical application prospects.

[0065] The above only describes the embodiments of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the scope of the claims of the present application.

Claims

1. A method of treating waste, characterized by, The application relates to a hydrogen production method and device. The catalyst is a multi-core coordination compound, and the multi-core coordination compound is obtained by combining a core with a hydroxyl-containing ligand; the core in the catalyst is two or more of an aluminum core, a silicon core, a nickel core and a calcium core; the heating temperature is 400-600 DEG C. The sludge contains a large amount of cellulose material, and cellulose-based organic matter is first generated into CO2 and CH4 under the action of the hydroxyl-containing ligand; the multi-core catalyst containing aluminum, silicon, nickel and calcium has a reduction effect and can realize CH4 reforming to generate CO2 and H2 under water vapor conditions; CO2 is absorbed by Ca in the carbide slag to generate CaCO3, thereby realizing efficient separation of H2 and CO2 and improving H2 purity. The sludge contains C, N, H, O and S elements, and the content of C, N, H, O and S in the sludge is 42.5-52.5%, 5.7-6.9%, 6.2-6.5%, 5.4-8.3% and 3.2-4.7% respectively.

2. The method of disposing of waste according to claim 1, wherein, The carbide slag contains Ca (OH) 2, and the mass fraction of Ca in the carbide slag is 60-70%.

3. The method of disposing of waste material of claim 1, wherein, The mass ratio of the dried sludge to the carbide slag is 2:1-5:

1.

4. The method of disposing of waste material of claim 1, wherein, The adding amount of the catalyst is 3-7% of the total mass of the mixed sludge and carbide slag.

5. The method of disposing of waste material of claim 1, wherein, The catalyst is a multi-core containing aluminum, silicon, nickel and calcium as the core, and a hydroxyl-containing ligand is combined to obtain a multi-core coordination compound, wherein the mass fraction of aluminum, silicon, nickel and calcium in the multi-core is 5-20 parts, 3-15 parts, 30-55 parts and 6-10 parts respectively.

6. The method of disposing of waste material of claim 1, wherein, The carbide slag is crushed before the sludge and the carbide slag are mixed.

7. The method of disposing of waste material of claim 1, wherein, The sludge and the carbide slag are mixed and then heated, and the heating temperature is 400-600 DEG C.

8. The method of disposing of waste material of claim 1, wherein, ​

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