Method for synergistically preparing high-strength ceramsite by utilizing river and lake bottom mud and oil sludge incineration dry slag

Abstract

The invention discloses a method for synergistically preparing high-strength ceramsite from river and lake bottom mud and oil sludge incineration dry residues, and relates to the field of solid waste treatment. The method comprises the following steps: respectively pretreating river and lake bottom mud, oil sludge incineration dry slag and lithium slag to obtain dry powder, and uniformly mixing the dry powder with quartz sand; adding a binder and water to prepare a ceramsite blank body; the preparation method comprises the following steps: carrying out constant temperature drying treatment, preheating, sintering and cooling to obtain the high-strength ceramsite, with the sintering temperature being 1110-1130 DEG C and the sintering time being 10-30 min. The curing of heavy metals in the oil sludge incineration dry residues is realized, the high-strength ceramsite is prepared by synergistically utilizing the river and lake bottom mud and the oil sludge incineration dry residues, the problem of storage and accumulation of solid wastes is solved, the resource utilization of the solid wastes is also realized, no other supplements are needed except a small amount of HPMC binder and quartz sand are added in the preparation process, and the resource consumption is reduced.

Description

Technical Field

[0001] This invention relates to the field of solid waste treatment, and in particular to a method for synergistically preparing high-strength ceramsite using river and lake bottom sediment and oil sludge incineration dry residue. Background Technology

[0002] River and lake sediment is an important component of aquatic ecosystems. It is a long-term sedimentary mixture of natural components and anthropogenic pollutants, posing a certain threat to aquatic ecological security. The volume of sediment generated annually through river and lake dredging is enormous. How to reduce its volume and dispose of it harmlessly has become an important research topic. Landfilling prevents effective resource utilization, while agricultural use fails to guarantee fertility. The main components of sediment are SiO2 and Al2O3, in addition to certain amounts of Na2O, K2O, MgO, CaO, Fe2O3, and FeO. These components form the material basis for firing ceramsite, making the utilization of sediment as a building material possible.

[0003] Oil sludge is a common solid waste in the petrochemical industry. Common treatment methods include incineration, pyrolysis, and landfill. Untreated oil sludge has a high content of petroleum hydrocarbons, and direct use in the production of ceramsite may pose safety risks. Landfilling, on the other hand, fails to achieve resource utilization. Incineration significantly reduces the petroleum hydrocarbon content in the dried oil sludge residue, improving the safety of ceramsite production. Furthermore, the dried oil sludge residue contains abundant SiO2 and Al2O3, key components for ceramsite skeletal structure, demonstrating its potential for ceramsite production. However, the dried oil sludge residue contains various heavy metals and other toxic substances, requiring careful consideration during resource utilization.

[0004] Currently, there are many studies on firing river and lake sediments and oily sludge into ceramsite separately, but there is a lack of research on the synergistic use of the two to prepare ceramsite. Moreover, existing research on the preparation of solid waste-based ceramsite has some problems: 1) The proportion of solid waste added is low, and a small amount of addition cannot achieve large-scale reduction of solid waste, which is not conducive to solving the problem of large-scale solid waste accumulation; 2) The proportion of natural materials such as clay added is high, which will cause a large consumption of resources and is not conducive to ecological and environmental protection; 3) The mechanical properties of ceramsite are not outstanding, and it cannot be widely used in various scenarios in actual engineering. Summary of the Invention

[0005] This invention provides a method for preparing high-strength ceramsite using the dry residue from the incineration of river and lake bottom sediment and oil sludge, supplemented with lithium slag and quartz sand, to achieve harmless treatment and resource utilization of solid waste, and to solve the difficulties in oil sludge disposal and heavy metal solidification.

[0006] This invention discloses a method for co-preparing high-strength ceramsite using river and lake bottom sediment and oil sludge incineration residue, the method comprising:

[0007] 1) Pre-treat river and lake bottom sediment, oil sludge incineration residue and lithium slag to obtain dry powder, and mix the three dry powders with 200 mesh quartz sand.

[0008] 2) Add hydroxypropyl methylcellulose solution as a binder to the mixture in step 1), add water to mix the raw materials evenly, and make ceramsite embryos of uniform size.

[0009] 3) The ceramsite blank is dried at a constant temperature, then preheated and sintered. After cooling, high-strength ceramsite can be obtained. The sintering temperature is 1110-1130 ℃ and the sintering time is 10-30 min.

[0010] Further, the pretreatment method in step 1) is as follows: the river and lake bottom mud is separated from the waste and the part containing tar is removed; the treated river and lake bottom mud, oil sludge incineration residue and lithium slag are placed together in a constant temperature drying oven and dried to constant weight; the dried solid waste material is removed and crushed by a grinding mill and passed through a 200-mesh sieve to obtain dry powder with a particle size of less than 0.075 mm.

[0011] Furthermore, the mass ratio of the river and lake bottom sediment, the dry residue from oil sludge incineration, and the lithium slag is 5:1 to 1:1.

[0012] Furthermore, the composition of the river and lake bottom sediment is: SiO2: 20~60%, Al2O3: 5~40%; the composition of the oil sludge incineration dry residue is: SiO2: 20~70%, Al2O3: 5~45%; and the composition of the lithium slag is: SiO2: 20~60%, Al2O3: 5~45%.

[0013] Furthermore, the ceramic raw materials contain SiO2, Al2O3, Fe2O3, CaO, MgO, Na2O and K2O; wherein the mass percentages of SiO2 and Al2O3 are 48%–70% and 10%–23% respectively, and the sum of the mass percentages of Fe2O3, CaO, MgO, Na2O and K2O is 13%–26%.

[0014] Furthermore, in step 2), the mass concentration of the hydroxypropyl methylcellulose solution is 1% to 2%, and the amount of water added is 30% to 35% of the mass of the ceramic pellet embryo.

[0015] Furthermore, the process of drying the ceramsite embryo at a constant temperature in step 3) specifically involves placing the ceramsite embryo in a constant temperature drying oven at 105 ℃ for more than 4 hours.

[0016] Furthermore, the preheating temperature in step 3) is 600–800 °C, and the preheating time is 10–30 min.

[0017] Further, in step 3), the sintering temperature is 1120–1130 °C, and the sintering time is 10–30 min.

[0018] Furthermore, the high-strength ceramsite meets the following properties: compressive strength ≥ 15.0 MPa, bulk density ≤ 1100 kg / m³. 3 Water absorption rate <1.5%.

[0019] The present invention utilizes river and lake bottom sediment (providing a matrix), oily sludge (supplementing silicon and aluminum + pre-detoxification), and lithium slag (lowering melting temperature + promoting densification + solidifying heavy metals) to achieve the triple goals of 100% resource utilization of solid waste, harmless treatment of heavy metals, and high performance of ceramsite through complementary components, low-temperature co-melting, and synergistic solidification mechanisms. This completely solves the core problems of solid waste stockpiling, consumption of natural resources, and insufficient mechanical properties of ceramsite.

[0020] River and lake sediment: provides the main silicon and aluminum components (SiO2 20~60%, Al2O3 5~40%), which are the matrix materials for ceramsite. Its rich Fe2O3, CaO and other oxides form a liquid phase during sintering, promoting particle bonding.

[0021] Oil sludge incineration dry residue: replenishes silicon and aluminum components (SiO2 20~70%, Al2O3 5~45%), while its high-temperature pretreatment (incineration) significantly reduces the petroleum hydrocarbon content, solving the safety risks of direct incineration. Heavy metals (such as Hg, As) in the dry residue are solidified in the ceramic particle glass phase during sintering, avoiding secondary pollution.

[0022] Lithium-containing compounds (such as Li2O) can be used as mineralizers to significantly reduce sintering temperature (1120~1130℃), shorten sintering time (10~30 min), promote the formation of a densified structure, and improve the strength of ceramic particles.

[0023] Heavy metals in oily sludge undergo ion exchange with lithium ions in lithium slag, forming stable silicate mineral phases (such as spodumene structure), thus achieving chemical fixation of heavy metals. Clay minerals (such as kaolinite) in river and lake sediments further capture free heavy metals through adsorption, and multiple mechanisms ensure that leaching toxicity meets standards.

[0024] The mass ratio of the three components (5:1 to 1:1) results in a total solid waste content exceeding 90%, requiring only a small amount of quartz sand to adjust the composition, achieving large-scale volume reduction. Compared to traditional technologies (such as those using only 30% bottom sludge), this invention eliminates the need for natural clay, completely solving the resource consumption problem. Pretreatment (incineration) of the dry oil sludge removes organic toxins and solidifies heavy metals through sintering; lithium slag enhances the solidification effect, ensuring the leaching toxicity of the ceramsite meets standards. The principle of the bio-based stabilizer technology is consistent with this synergistic solidification mechanism. The interaction of these three components results in a ceramsite compressive strength ≥15.0 MPa (traditional solid waste ceramsite only 5~8 MPa), bulk density ≤1100 kg / m³, and water absorption <1.5%. The fluxing effect of lithium slag and the optimization of the silicon-aluminum composition are key, avoiding the low strength defects of the non-fired method.

[0025] This invention aims to achieve the resource utilization of two common solid wastes: river and lake sediment, oil sludge incineration residue, and lithium slag. Co-utilization of solid wastes, through the rational blending of solid wastes with different characteristics, can fully utilize the properties of each component, thereby effectively improving the treatment and utilization efficiency of solid wastes. Traditional ceramsite preparation mainly utilizes natural materials such as shale and clay. With the increasing awareness of ecological protection and resource recycling, the use of solid wastes to replace natural materials in ceramsite preparation has shown promising prospects in recent years. Using oil sludge and sediment in ceramsite preparation can not only save natural resources but also solve the problem of solid waste disposal, enabling the recycling of solid waste resources and creating new economic value.

[0026] This invention achieves the solidification of heavy metals in dry residue from oil sludge incineration and synergistically utilizes river and lake bottom sediment and dry residue from oil sludge incineration to prepare high-strength ceramsite. This not only solves the problem of solid waste storage and accumulation but also realizes its resource utilization. In the preparation process, apart from adding a small amount of HPMC binder and quartz sand, no other supplementary agents are required, thus reducing resource consumption. Attached Figure Description

[0027] Figure 1 A schematic diagram of the process flow for the method of firing ceramsite provided by the present invention;

[0028] Figure 2 The image shown is a scanning electron microscope (SEM) image (×20000) of the ceramsite prepared in Example 1 of this invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the spirit of the contents disclosed in the present invention will be described in detail below. After understanding the embodiments of the present invention, any person skilled in the art can make changes and modifications based on the technology taught in the present invention without departing from the spirit and scope of the present invention.

[0030] The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0031] Example 1

[0032] This embodiment provides a method for co-preparing high-strength ceramsite using river and lake bottom sediment and dry residue from oil sludge incineration, specifically including the following steps:

[0033] (1) Pretreatment of solid waste raw materials: Separate the garbage mixed in the river and lake bottom mud and remove the part containing tar. Transfer the obtained bottom mud, oil sludge incineration dry residue and lithium slag together into a 105 ℃ constant temperature box to dry to constant weight, then crush it with a grinder and pass it through a 200 mesh sieve for later use.

[0034] The river and lake sediment used in this example came from Sanyong Lake in Daqing City, the dry residue from oil sludge incineration also came from Daqing, and the lithium slag came from Shandong, which is spodumene lithium slag.

[0035] (2) XRF testing and elemental analysis were performed on the treated river and lake bottom mud powder, oil sludge incineration dry residue, lithium slag powder (the composition of the river and lake bottom mud is: SiO2: 58.56%, Al2O3: 15.90%; the composition of the oil sludge incineration dry residue is: SiO2: 51.35%, Al2O3: 13.54%; the composition of the lithium slag is: SiO2: 49.08%, Al2O3: 19.24%) and the purchased 200-mesh quartz sand powder (the SiO2 content in the quartz sand is 96.00%) to obtain the proportion of C and S elements and the content of Na2O, K2O, MgO, CaO and Fe2O3 in the raw materials (the mass proportions of SiO2 and Al2O3 are 48%~70% and 10%~23% respectively, and the sum of the mass proportions of Fe2O3, CaO, MgO, Na2O and K2O is 13%~26%). Based on this, the composition of the ceramsite raw material was set as follows: river and lake bottom mud: dry residue from oil sludge incineration: lithium slag: quartz sand in a ratio of 3:3:3:1. Several powders were mixed in proportion, 1% HPMC solution was added as a binder, and 30% water was added to mix the raw material evenly before granulation.

[0036] (3) The spheres are placed in a constant temperature oven at 105 ℃ and dried for 4 h to remove the moisture. Then they are placed in a sintering device and preheated at 600 ℃ for 20 min. Then the temperature is raised to 1120 ℃ and held for 15 min. After cooling to room temperature, high-strength ceramic granules can be obtained.

[0037] The ceramsite obtained in this embodiment has a particle size of 10–25 mm, a compressive strength of 26.54 MPa, and a bulk density of 1031 kg / m³. 3The water absorption rate is 0.83% in 1 hour, and its performance meets the requirements for high-strength ceramsite in the building materials industry standard "Sludge Ceramsite" (JC / T 2621-2021).

[0038] The heavy metal leaching concentrations of high-strength ceramsite are: copper 0.014 mg / L, manganese 0.021 mg / L, chromium 0.013 mg / L, zinc 0.059 mg / L, and lead 0.010 mg / L, all of which are lower than the concentration limits of hazardous components in the leachate specified in the "Identification Standard for Hazardous Waste: Leaching Toxicity Identification" (GB 5085.3-2007).

[0039] In this embodiment, the sulfur content in the lithium slag reaches 3.29%, and if calculated as SO3, its SO3 content is 14.48%. Sulfur-containing substances can decompose and produce gas at high temperatures. The dry sludge contains incompletely decomposed organic matter, and its carbon content is 6.52%. Carbon can also decompose and produce gas at high temperatures, which together promote the formation of a dense structure in the ceramsite.

[0040] The flue gas and wastewater generated in the entire process described above must be specially treated to meet the standards before they can be discharged.

[0041] Example 2

[0042] This embodiment provides a method for co-preparing high-strength ceramsite using river and lake bottom sediment and dry residue from oil sludge incineration, specifically including the following steps:

[0043] (1) Pretreatment of solid waste raw materials: Separate the garbage mixed in the river and lake bottom mud and remove the part containing tar. Transfer the obtained bottom mud, oil sludge incineration dry residue and lithium slag together into a 105 ℃ constant temperature box to dry to constant weight, then crush it with a grinder and pass it through a 200 mesh sieve for later use.

[0044] The river and lake sediment used in this example came from Sanyong Lake in Daqing City, the dry residue from oil sludge incineration also came from Daqing, and the lithium slag came from Shandong, which is spodumene lithium slag.

[0045] (2) The treated river and lake bottom sediment powder, oil sludge incineration dry residue, lithium slag powder (the composition of the river and lake bottom sediment is: SiO2: 58.56%, Al2O3: 15.90%; the composition of the oil sludge incineration dry residue is: SiO2: 51.35%, Al2O3: 13.54%; the composition of the lithium slag is: SiO2: 49.08%, Al2O3: 19.24%) and the purchased 200-mesh quartz sand powder ( X-ray fluorescence spectroscopy (XRF) and elemental analysis were performed on the quartz sand (containing 96.00% SiO2) to determine the proportions of C and S elements and the contents of Na2O, K2O, MgO, CaO, and Fe2O3 in several raw materials (the mass proportions of SiO2 and Al2O3 were 48%–70% and 10%–23%, respectively, and the sum of the mass proportions of Fe2O3, CaO, MgO, Na2O, and K2O was 13%–26%). Based on this, the composition of the ceramsite raw material was set as river and lake bottom mud: dry oil sludge incineration: lithium slag: quartz sand in a ratio of 5:1:3:1. The powders were mixed in the specified proportions, 1% HPMC solution was added as a binder, and 30% water was added to mix the raw materials thoroughly before granulation.

[0046] (3) The spheres are placed in a constant temperature oven at 105 ℃ and dried for 4 h to remove the moisture. Then they are placed in a sintering device and preheated at 600 ℃ for 20 min. Then the temperature is raised to 1120 ℃ and kept at 15 min. After cooling to room temperature, high-strength ceramsite can be obtained.

[0047] The ceramsite obtained in this embodiment has a particle size of 10–25 mm, a compressive strength of 23.72 MPa, and a bulk density of 1017 kg / m³. 3 The water absorption rate is 0.99%, and its performance meets the requirements for high-strength ceramsite in the building materials industry standard "Sludge Ceramsite" (JC / T 2621-2021). The heavy metal leaching concentrations of the high-strength ceramsite are: copper 0.002 mg / L, manganese 0.014 mg / L, chromium 0.010 mg / L, zinc 0.032 mg / L, and lead 0.008 mg / L, all of which are lower than the concentration limits of hazardous components in the leachate specified in "Identification Standard for Hazardous Waste: Leaching Toxicity Identification" (GB 5085.3-2007). The flue gas and wastewater generated in the entire process described above must be specially treated to meet standards before being discharged.

[0048] The above description is merely a specific embodiment of this application and is not intended to limit the present invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for co-preparing high-strength ceramsite using river and lake bottom sediment and oil sludge incineration residue, characterized in that, The method includes: 1) Pre-treat river and lake bottom sediment, oil sludge incineration residue and lithium slag to obtain dry powder, and mix the three dry powders with 200 mesh quartz sand. 2) Add hydroxypropyl methylcellulose solution as a binder to the mixture in step 1), add water to mix the raw materials evenly, and make ceramsite embryos of uniform size. 3) The ceramsite blank is dried at a constant temperature, then preheated and sintered. After cooling, high-strength ceramsite can be obtained. The sintering temperature is 1110-1130 ℃ and the sintering time is 10-30 min.

2. The method for co-preparing high-strength ceramsite using river and lake bottom sediment and oil sludge incineration residue as described in claim 1, characterized in that, The pretreatment method in step 1) is as follows: the river and lake bottom mud is separated from the waste and the part containing tar is removed; the treated river and lake bottom mud, oil sludge incineration residue and lithium slag are placed together in a constant temperature drying oven and dried to constant weight; the dried solid waste material is removed and crushed by a grinding mill and passed through a 200-mesh sieve to obtain dry powder with a particle size of less than 0.075 mm.

3. A method for co-preparing high-strength ceramsite using river and lake bottom sediment and oil sludge incineration residue as described in claim 1 or 2, characterized in that, The mass ratio of the river and lake bottom sediment, the dry residue from oil sludge incineration, and the lithium slag is 5:1 to 1:

1.

4. The method for co-preparing high-strength ceramsite using river and lake bottom sediment and oil sludge incineration residue as described in claim 3, characterized in that, The composition of the river and lake bottom sediment is: SiO2: 20~60%, Al2O3: 5~40%; the composition of the oil sludge incineration dry residue is: SiO2: 20~70%, Al2O3: 5~45%; the composition of the lithium slag is: SiO2: 20~60%, Al2O3: 5~45%.

5. The method for co-preparing high-strength ceramsite using river and lake bottom sediment and oil sludge incineration residue as described in claim 1, characterized in that, The ceramic raw materials contain SiO2, Al2O3, Fe2O3, CaO, MgO, Na2O and K2O; wherein the mass percentages of SiO2 and Al2O3 are 48%–70% and 10%–23% respectively, and the total mass percentages of Fe2O3, CaO, MgO, Na2O and K2O are 13%–26%.

6. The method for co-preparing high-strength ceramsite using river and lake bottom sediment and oil sludge incineration residue as described in claim 1, characterized in that, In step 2), the mass concentration of the hydroxypropyl methylcellulose solution is 1% to 2%, and the amount of water added is 30% to 35% of the mass of the ceramic pellet embryo.

7. The method for co-preparing high-strength ceramsite using river and lake bottom sediment and oil sludge incineration residue according to claim 1, characterized in that, Step 3) describes the process of drying the ceramsite embryo at a constant temperature by placing it in a 105℃ constant temperature drying oven for more than 4 hours.

8. The method for co-preparing high-strength ceramsite using river and lake bottom sediment and oil sludge incineration residue according to claim 1, characterized in that, The preheating temperature in step 3) is 600–800 °C, and the preheating time is 10–30 min.

9. The method for co-preparing high-strength ceramsite using river and lake bottom sediment and oil sludge incineration residue according to claim 1, characterized in that, In step 3), the sintering temperature is 1120–1130 °C and the sintering time is 10–30 min.

10. The method for co-preparing high-strength ceramsite using river and lake bottom sediment and oil sludge incineration residue according to claim 1, characterized in that, The high-strength ceramsite described above meets the following properties: compressive strength ≥ 15.0 MPa, bulk density ≤ 1100 kg / m³. 3 Water absorption rate <1.5%.

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