Method for extracting alkali solution from soda ash waste alkali mud and calcium carbide hydrolysis by-product calcium carbide slag

Abstract

This invention discloses a method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide slag, a byproduct of acetylene production via calcium carbide hydrolysis. It relates to the field of industrial solid waste utilization technology and includes: (1) processing each batch of new sludge powder raw material using a countercurrent extraction process to obtain a concentrated leachate A rich in sodium carbonate and sodium silicate, and a final residue Z rich in silica; (2) subjecting the concentrated leachate A to ultrasonic treatment to separate and obtain a clear alkali metal salt solution B; (3) adding calcium carbide slag powder to the clear alkali metal salt solution B and performing a heating and stirring reaction to obtain a supernatant C containing sodium hydroxide; (4) heating and evaporating the supernatant C to concentrate and obtain a sodium hydroxide solution product. This invention can convert two types of waste residues into sodium hydroxide and sodium silicate solutions with clearly defined compositions and significant alkalinity. The purity of these solutions is sufficient to meet the application needs of industrial fields where the purity of the alkali solution is not high, thus broadening the pathways for high-value utilization of waste.

Description

Technical Field

[0001] This invention relates to the field of industrial solid waste utilization technology, specifically to a method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide slag, a byproduct of acetylene production via calcium carbide hydrolysis. Background Technology

[0002] Alkali sludge is a solid waste generated during the industrial production of sodium silicate (sodium silicate). It has a pH value of 11-12 and is highly alkaline. It is mainly composed of silicon dioxide (SiO2), sodium silicate (Na2SiO3), and sodium carbonate (Na2CO3).

[0003] Carbide slag is a byproduct of the hydrolysis of calcium carbide to produce acetylene in the calcium carbide PVC process. It has a pH value of 12-13 and its main phase composition is Ca(OH)2. The dumping of carbide slag not only occupies land resources, but also causes serious pollution to soil and water bodies due to its strong alkalinity.

[0004] Currently, the industry is still exploring ways to treat and utilize the highly alkaline waste residues, alkali sludge and carbide slag. Common approaches include separate neutralization treatment and using them as building material raw materials or roadbed fillers. However, these methods often suffer from incomplete treatment, low added value of the products, or failure to simultaneously address the alkalinity of the two waste residues and the problem of large-scale stockpiling. In particular, a mature process has yet to be developed that can effectively co-process the two waste residues and directly extract high-value chemical products (such as sodium hydroxide and sodium silicate).

[0005] Therefore, developing a new method that can organically combine alkali sludge and carbide slag to achieve efficient conversion of their alkaline components and resource recovery is of urgent need and important practical significance for fundamentally solving the environmental pollution problems of these two waste residues and creating economic benefits. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide a method for reacting alkaline sludge with carbide slag to produce sodium hydroxide and sodium silicate, thereby realizing the reuse of waste. The method of this invention extracts the soluble strong alkaline components from the alkaline sludge and uses the calcium components in the carbide slag to convert them into stable precipitates, thereby significantly reducing the leaching alkalinity and environmental hazards of the two waste residues from the source, and simultaneously producing useful chemical products. It brings economic benefits while protecting the environment and has broad application prospects.

[0007] The technical solution of this invention is: a method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide slag, a byproduct of acetylene production via calcium carbide hydrolysis, characterized by comprising the following steps: (1) Each batch of new alkaline mud powder raw material is processed by countercurrent extraction to obtain concentrated leachate A rich in sodium carbonate and sodium silicate and final residue Z rich in silica. (2) The concentrated leachate A is subjected to ultrasonic treatment to separate the suspended matter containing free silica, and a clear alkali metal salt solution B is obtained. (3) Add carbide slag powder to the clear alkali metal salt solution B, heat and stir to react, and after the reaction is completed, separate the solid and liquid to obtain the supernatant C containing sodium hydroxide; (4) The supernatant C containing sodium hydroxide is heated and evaporated to raise the pH value to the preset requirement, thereby obtaining a sodium hydroxide solution product. The preferred preset pH value is 13.8-14.2.

[0008] A preferred method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide residue (a byproduct of acetylene production via calcium carbide hydrolysis), wherein the countercurrent extraction process in step (1) specifically includes the following cyclic steps: (a) Primary extraction: The secondary concentrated leachate from the previous batch of the process is used as the extractant and mixed with the new alkaline mud powder raw material of the current batch for extraction. After solid-liquid separation, concentrated leachate A and primary leaching residue z1 are obtained. (b) Deep extraction: Fresh water is used as the extraction agent and mixed with the primary extract residue z1 obtained from the initial extraction. After solid-liquid separation, a secondary concentrated extract b1 and the final residue Z are obtained. In the first batch of alkaline mud powder raw material, step (a) uses fresh water as the extractant; the secondary concentrated leachate b1 obtained in step (b) of the current batch is recycled as the extractant for the initial extraction of the next batch of raw material.

[0009] A more preferred method for extracting an alkaline solution from the alkaline mud of sodium silicate waste and the calcium carbide slag, a byproduct of acetylene production by calcium carbide hydrolysis, wherein the mixing and extraction in steps (a) and (b) are carried out under a water bath at 60-80°C with stirring for 1-2 hours.

[0010] More preferably, in the method for extracting alkaline solution from the alkali mud of sodium silicate waste and the calcium carbide slag byproduct of acetylene production by hydrolysis of calcium carbide, the mass ratio of the new alkali mud powder raw material to the extractant in step (a) is 1:5~7, and the mass ratio of the new alkali mud powder raw material to the extractant in step (b) is also 1:5~7.

[0011] The preferred method for extracting alkaline solution from sodium silicate waste sludge and calcium carbide slag, a byproduct of acetylene production by hydrolysis of calcium carbide, is as follows: the ultrasonic treatment time in step (2) is 0.5 to 1 hour.

[0012] The preferred method for extracting alkaline solution from alkali sludge from sodium silicate waste and calcium carbide slag, a byproduct of acetylene production by hydrolysis of calcium carbide, involves heating and stirring the reaction in step (3) under a water bath at 60-80°C for 1-1.5 hours.

[0013] The preferred method for extracting alkaline solution from sodium silicate waste sludge and calcium carbide slag, a byproduct of acetylene production by hydrolysis of calcium carbide, is that the mass ratio of the calcium carbide slag powder added in step (3) to the sludge powder raw material in step (1) is 1:6~8.

[0014] The preferred method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide residue (a byproduct of acetylene production via calcium carbide hydrolysis) further includes the following step (5). (5) Dry and pulverize the final residue Z obtained after countercurrent extraction in step (1) to obtain residue powder rich in active silica; add the residue powder to the sodium hydroxide solution product obtained in step (4).

[0015] A more preferred method for extracting alkaline solution from sodium silicate waste sludge and calcium carbide slag, a byproduct of acetylene production by calcium carbide hydrolysis, involves step (5) of heating and stirring the reaction under a water bath at 60-80°C for 1.5-2.5 hours to prepare sodium silicate solution product.

[0016] A more preferred method for extracting alkaline solution from sodium silicate waste sludge and calcium carbide slag, a byproduct of acetylene production by hydrolysis of calcium carbide, wherein the mass ratio of the residue dry powder in step (5) to the sludge powder raw material in step (1) is 1~1.5:20.

[0017] The stirring involved in this invention has a stirring speed range of 300~600 r / min.

[0018] The beneficial effects of this invention are: 1. After heating and stirring in a water bath, sodium carbonate and sodium silicate in the alkaline mud dissolve in the water. Countercurrent extraction is used to improve extraction efficiency. Ultrasonic treatment is used to remove free silica, and a supernatant containing sodium carbonate and sodium silicate is extracted. Calcium carbide slag powder is added to the supernatant and heated and stirred in a water bath to generate sodium hydroxide, calcium carbonate, and calcium silicate. Calcium carbonate and calcium silicate precipitate to the bottom, and the supernatant is a sodium hydroxide solution.

[0019] 2. The countercurrent extraction process employed in this invention constructs a continuous high concentration gradient driving force by using the previous batch of medium-concentration leachate (i.e., secondary concentrated leachate b1) to extract new material, using the high-concentration leachate (i.e., concentrated leachate A) as the product liquid, and washing the first batch of leach residue z1 with fresh water. This not only significantly improves the leaching efficiency and extraction rate of sodium carbonate and sodium silicate in alkaline mud, but also greatly reduces the process water consumption, realizes the recycling of water resources, reduces the energy consumption of subsequent evaporation and concentration, and improves the overall economic and environmental benefits of the process.

[0020] 3. This invention utilizes the "cavitation effect" generated by ultrasound in liquids. The intense formation and collapse of tiny bubbles in the liquid produce localized shock waves and microjets, which peel away the gel layer on the particle surface, pulverize agglomerates, and penetrate deep into the micropores of the particles. By pre-removing free silica suspensions, a clear alkali metal salt solution is obtained. This avoids silica, as an inert impurity, interfering with mass transfer and reaction processes in the subsequent reaction with carbide slag, ensuring that the sodium hydroxide formation reaction (causticization reaction) can proceed more fully and efficiently.

[0021] 4. The residue powder obtained after drying the precipitated alkaline mud slurry following countercurrent extraction is added to a sodium hydroxide solution, heated and stirred in a water bath. The active silica in the alkaline mud reacts with the sodium hydroxide to generate a sodium silicate solution. This invention, by sequentially extracting alkaline mud through a water bath to obtain sodium carbonate and sodium silicate solutions, and then ultrasonically treating the supernatant, organically combines the calcium carbide slag, a byproduct of acetylene production from calcium carbide hydrolysis, to prepare sodium hydroxide and sodium silicate solutions. This achieves waste utilization and has certain economic benefits. Simultaneously, it reduces the alkalinity of the alkaline mud from sodium silicate waste and the calcium carbide slag from acetylene production from calcium carbide hydrolysis, which is beneficial to environmental protection. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This invention relates to a process flow diagram of a method for extracting an alkaline solution from calcium carbide slag, a byproduct of acetylene production via the hydrolysis of sodium silicate waste sludge and calcium carbide.

[0024] Figure 2 This is a flow chart of the countercurrent extraction process of the present invention.

[0025] Figure 3 The image shown is an FTIR image of the precipitated slurry after the reaction of alkali mud supernatant and carbide slag, which is involved in this invention.

[0026] Figure 4 The image shows the XRD pattern of the precipitated slurry after the reaction of alkali mud supernatant and carbide slag, which is involved in this invention.

[0027] Figure 5 This is a test diagram of the flexural strength of the mechanical properties involved in this invention.

[0028] Figure 6 This is a test diagram of the compressive strength of the mechanical properties involved in this invention. Detailed Implementation

[0029] The following will describe the concept and technical effects of the present invention clearly and completely with reference to the embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0030] Currently, there is no mature process in the existing technology that can effectively co-process the alkali sludge (a waste product of sodium silicate) and the calcium carbide slag (a byproduct of acetylene production from calcium carbide hydrolysis) and directly extract high-value chemical products (such as sodium hydroxide and sodium silicate). This invention provides a new method for the effective utilization of alkali sludge and calcium carbide slag, utilizing the reaction between the alkali sludge and calcium carbide slag to generate sodium hydroxide and sodium silicate, thus achieving the reuse of waste materials.

[0031] Example 1 like Figure 1 As shown, a method for extracting an alkaline solution from the alkali sludge (a waste product from the production of sodium silicate) and the calcium carbide slag (a byproduct of acetylene production via calcium carbide hydrolysis) includes the following steps: (1) Solid waste alkali mud is dried and crushed to obtain alkali mud powder raw material. Each batch of new alkali mud powder raw material is processed by countercurrent extraction process to obtain concentrated leachate A rich in sodium carbonate and sodium silicate and final residue Z rich in silica. like Figure 2 As shown, the countercurrent extraction process specifically includes the following cyclic steps: (a) Primary extraction: The secondary concentrated leachate from the previous batch of the process is used as the extractant and mixed with the new alkaline mud powder raw material of the current batch for extraction. After solid-liquid separation, concentrated leachate A and primary leaching residue z1 are obtained. (b) Deep extraction: Fresh water is used as the extraction agent and mixed with the primary extract residue z1 obtained from the initial extraction. After solid-liquid separation, a secondary concentrated extract b1 and the final residue Z are obtained. In the first batch of alkaline mud powder raw material, step (a) uses fresh water as the extractant; the secondary concentrated leachate b1 obtained in step (b) of the current batch is recycled as the extractant for the initial extraction of the next batch of raw material.

[0032] In the above countercurrent extraction process, the mass ratio of the new batch of alkaline mud powder raw material to the extractant in steps a and b is 1:5~7 (the mass ratio in this embodiment is 1:6). The mixing extraction water bath temperature in steps a and b is 60~80℃ (80℃ in this embodiment), the stirring speed is 400r / min, and the stirring time is 1~2h (2h in this embodiment).

[0033] (2) Place the concentrated leachate A in an ultrasonic cleaning tank or use an ultrasonic probe for ultrasonic treatment for 0.5-1h to separate the suspended matter containing free silica and obtain a clear alkali metal salt solution B. (3) Add carbide slag powder to the clear alkali metal salt solution B. The mass ratio of carbide slag powder to the new batch of alkali mud powder in step (1) is 1:6-8 (specifically 1:7 in this embodiment). Heat and stir the reaction. The water bath temperature is 60~80℃ (specifically 80℃ in this embodiment), the stirring speed is 450r / min, and the stirring time is 1~1.5h (specifically 1.5h in this embodiment). The carbide slag powder reacts with sodium carbonate and sodium silicate in the supernatant (alkali metal salt solution B) to generate sodium hydroxide, calcium carbonate, and calcium silicate. Calcium carbonate and calcium silicate precipitate to the bottom, and the supernatant is a sodium hydroxide solution. After the reaction is completed, solid and liquid are separated to obtain supernatant C containing sodium hydroxide. The pH value is tested to be 13.6. (4) Heating and evaporating the supernatant C containing sodium hydroxide will only evaporate the water, and the sodium hydroxide will not evaporate and disappear. Increase the concentration of sodium hydroxide solution and increase the pH value to 14 to obtain sodium hydroxide solution product.

[0034] The steps (1) to (4) of preparing sodium silicate solution are the same as the above steps, and also include step (5), drying and pulverizing the final residue Z of step (1) to obtain residue dry powder rich in active silica; adding the residue dry powder to the target sodium hydroxide solution product obtained in step (4), and preparing sodium silicate solution by water bath heating and stirring, with water bath temperature of 60-80 ℃ (80 ℃ in this embodiment), stirring speed of 450 r / min, and stirring time of 1.5-2.5 h (1.5 h in this embodiment), and the mass ratio of the current batch of new alkali mud powder raw material in step (1) to the residue dry powder in step (5) is 20:1-1.5 (20:1 in this embodiment).

[0035] The XRF data of the sodium hydroxide solution product obtained in step (4) of this embodiment is shown in Table 1. The XRF data of the sodium silicate solution product obtained in step (5) of this embodiment is shown in Table 2. The chemical composition of the alkali mud powder raw material is shown in Table 3. The chemical composition of the precipitated alkali mud slurry (final residue Z) after extracting the supernatant is shown in Table 4.

[0036] Table 1. XRF / wt% for preparing sodium hydroxide solution from alkali mud and carbide slag

[0037] Table 2. XRF / wt% for preparing sodium silicate solution from alkaline mud and carbide slag

[0038] Table 3 Chemical composition of alkali sludge from sodium silicate production / wt%

[0039] Table 4 Chemical composition of precipitated alkaline mud slurry after extraction of supernatant / wt%

[0040] As shown in Tables 1 and 2, this invention successfully extracts a practically valuable alkaline solution from waste residue. Table 1 data shows that the obtained sodium hydroxide solution product has a significant sodium (Na) content, while the content of impurities such as calcium (Ca) and silicon (Si) is extremely low. This indicates that the silicon and calcium components in the alkali mud were effectively removed through ultrasonic separation and reaction with carbide slag, resulting in a high-purity alkaline solution (pH 14) with sodium hydroxide as the main component. Table 2 data shows that the prepared sodium silicate solution has a high content of both sodium (Na) and silicon (Si) elements, and the ratio is appropriate, confirming the successful synthesis of sodium silicate product from the active silica extracted from the residue and the self-made sodium hydroxide. These two sets of data directly demonstrate that this invention can convert two types of waste residue into sodium hydroxide and sodium silicate solutions with clearly defined compositions and significant alkalinity. The purity is sufficient to meet the application needs of industrial fields where high purity of the alkaline solution is not required (such as chemical intermediates, detergent additives, building material activators, etc.), broadening the pathways for high-value utilization of waste.

[0041] A comparison of Tables 3 and 4 shows that the process of this invention achieves deep dealkali removal and component optimization of alkali sludge, resulting in significant environmental benefits. Before treatment, the sodium oxide (Na2O) content in the alkali sludge (Table 3), representing alkalinity, was as high as 18.63%, while after countercurrent extraction, the sodium oxide content in the remaining residue (Table 4) decreased significantly to 7.83%. This key data comparison directly demonstrates that the process of this invention can efficiently extract soluble strong alkaline components from alkali sludge, reducing its residual alkalinity by approximately 58%, fundamentally and significantly weakening the pollution potential of the alkali sludge, and significantly reducing the environmental risks of its subsequent storage or disposal, resulting in outstanding environmental benefits. Simultaneously, the silica (SiO2) content in the residue increased from 73.28% to 81.47%, making it a raw material with higher silica content and a more concentrated composition, which is more conducive to its subsequent resource utilization as a silicon source for the preparation of sodium silicate solution or as a building material raw material.

[0042] FTIR of the precipitate after the reaction of alkali mud supernatant and carbide slag is as follows: Figure 3 As shown, from Figure 3 It can be seen that the characteristic peaks of calcium carbonate (CaCO3) are: Figure 3 1430cm -1 The %T wavenumber in the vicinity is slightly lower than that of the surrounding area, indicating the presence of CO3. 2- Asymmetric tensile vibration; at 875cm -1The %T value in the vicinity is slightly lower than the wave number in the vicinity, which is consistent with CO3. 2- Out-of-plane bending vibration; at 712 cm -1 Nearby %T conforms to CO3 2- In-plane bending vibration. Data at 1430, 875, and 712 cm. -1 The absorption decreased to varying degrees in the vicinity, indicating the presence of calcium carbonate. Characteristic peak of calcium silicate (CaSiO3): 1000 cm⁻¹ -1 A strong and broad absorption peak of Si-O-Si was observed with a decrease in %T in the vicinity; 500 cm⁻¹ -1 The surrounding region has a generally low %T value, which is a common region for many silicates, combined with 1000cm. -1 The decrease in %T in the nearby interval indicates the presence of calcium silicate.

[0043] XRD patterns of the precipitated slurry after the reaction of alkali mud supernatant and carbide slag are as follows: Figure 4 As shown, from Figure 4 It can be known that: The characteristic peak position (2θ) of calcium carbonate (CaCO3) is as follows: There is an extremely strong diffraction peak near 29.4°, corresponding to its crystal plane. Data correspondence: 29.400°: intensity 27272.857 (strongest peak), interplanar spacing 0.3036 nm; 48.480°: intensity 4876.596, interplanar spacing 0.1876 nm; 39.400°: intensity 4604.613, interplanar spacing 0.2285 nm. The 29.400° peak is a typical main peak for calcite-type calcium carbonate, indicating the presence of calcium carbonate crystals in the sample.

[0044] Characteristic peak positions (2θ) of calcium silicate (CaSiO3): Multiple medium-intensity peaks are typically found in the range of 26°–35°. Corresponding data: 35.960°: intensity 3569.017, interplanar spacing 0.2495 nm; 43.140°: intensity 3929.067, interplanar spacing 0.2095 nm. The peaks at 35.960° and 43.140° are characteristic peaks of calcium silicate, indicating the presence of a calcium silicate phase in the sample.

[0045] In summary, the characterization results of FTIR and XRD corroborate each other, jointly confirming that in the reaction of step (3), calcium hydroxide in carbide slag reacts fully with sodium carbonate and sodium silicate in alkaline mud extract to generate calcium carbonate and calcium silicate precipitates.

[0046] Example 2 The sodium hydroxide solution product and sodium silicate solution product prepared in the examples were used as activators to prepare test blocks according to the dosage in Table 5. The slag, activator and standard sand were mixed at a mass ratio of 450:225:1350. The test block prepared with sodium hydroxide solution product was numbered GN and the test block prepared with sodium silicate solution product was numbered GW.

[0047] Table 5. Mixing ratio (g)

[0048] The flexural and compressive strength of specimens GN and GW were tested, and the results are as follows: Figure 5 As shown, from Figure 5 It can be seen that the flexural strength of both GN and GW increases continuously with age, reaching its peak at 28 days, which is consistent with the development of alkali-activated slag strength with hydration age. At all ages, the flexural strength of the GW group is significantly higher than that of the GN group, and the gap gradually widens with age: the GN group increases by 16.1% from 7 days to 28 days, while the GW group increases by 19.2% from 7 days to 28 days, with a larger increase in the later stages, and the most significant increase in strength at 28 days.

[0049] from Figure 6 It can be seen that the compressive strength of both GN and GW increases continuously with age, reaching its highest value at 28 days, and the increase is greater than that of flexural strength, demonstrating the advantage of alkali-activated slag in compressive strength. At all ages, the compressive strength of the GW group is higher than that of the GN group, and the gap also widens with age; the growth of both the GN and GW groups is relatively stable at 3d, 7d, and 28d, with the growth rate slowing down slightly in the later stages, but their absolute strength still leads.

[0050] from Figures 5-6 The mechanical property test results show that both the sodium hydroxide solution and sodium silicate solution products prepared in this invention can effectively activate slag activity as alkali activators, producing alkali-activated slag materials with good mechanical properties. The flexural and compressive strengths of the test blocks (GN and GW) prepared from both products steadily increased with age, reaching a peak at 28 days, demonstrating the typical strength development law of alkali-activated materials.

Claims

1. A method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide slag (a byproduct of acetylene production via calcium carbide hydrolysis), characterized in that... Includes the following steps: (1) Each batch of new alkaline mud powder raw material is processed by countercurrent extraction to obtain concentrated leachate A rich in sodium carbonate and sodium silicate and final residue Z rich in silica. (2) The concentrated leachate A is subjected to ultrasonic treatment to separate the suspended matter containing free silica, and a clear alkali metal salt solution B is obtained. (3) Add carbide slag powder to the clear alkali metal salt solution B, heat and stir to react, and after the reaction is completed, separate the solid and liquid to obtain the supernatant C containing sodium hydroxide; (4) The supernatant C containing sodium hydroxide is heated and evaporated to raise the pH value to the preset requirement, thereby obtaining the sodium hydroxide solution product.

2. The method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide slag (a byproduct of acetylene production via calcium carbide hydrolysis) as described in claim 1, characterized in that... The countercurrent extraction process described in step (1) specifically includes the following cyclic steps: (a) Primary extraction: The secondary concentrated leachate from the previous batch of the process is used as the extractant and mixed with the new alkaline mud powder raw material of the current batch for extraction. After solid-liquid separation, concentrated leachate A and primary leaching residue z1 are obtained. (b) Deep extraction: Fresh water is used as the extraction agent and mixed with the primary extract residue z1 obtained from the initial extraction. After solid-liquid separation, a secondary concentrated extract b1 and the final residue Z are obtained. In the first batch of alkaline mud powder raw material, step (a) uses fresh water as the extractant; the secondary concentrated leachate b1 obtained in step (b) of the current batch is recycled as the extractant for the initial extraction of the next batch of raw material.

3. The method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide slag (a byproduct of acetylene production via calcium carbide hydrolysis) as described in claim 2, characterized in that... In steps (a) and (b), the mixing and extraction were carried out under a water bath at 60-80°C with stirring for 1-2 hours.

4. The method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide slag (a byproduct of acetylene production via calcium carbide hydrolysis) as described in claim 2, characterized in that... The mass ratio of the new alkali mud powder raw material in step (a) to the extractant in step (a) is 1:5~7, and the mass ratio of the new alkali mud powder raw material in step (a) to the extractant in step (b) is also 1:5~7.

5. The method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide slag (a byproduct of acetylene production via calcium carbide hydrolysis) as described in claim 1, characterized in that... The ultrasonic treatment time in step (2) is 0.5 to 1 hour.

6. The method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide slag (a byproduct of acetylene production via calcium carbide hydrolysis) as described in claim 1, characterized in that... In step (3), the heating and stirring reaction is carried out in a water bath at 60~80℃ for 1~1.5 hours.

7. The method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide slag (a byproduct of acetylene production via calcium carbide hydrolysis) as described in claim 1, characterized in that... The mass ratio of the carbide slag powder added in step (3) to the alkali mud powder raw material in step (1) is 1:6~8.

8. The method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide slag (a byproduct of acetylene production via calcium carbide hydrolysis) as described in claim 1, characterized in that... It also includes the following step (5). (5) Dry and pulverize the final residue Z obtained after countercurrent extraction in step (1) to obtain residue powder rich in active silica; add the residue powder to the sodium hydroxide solution product obtained in step (4), heat and stir to react, and prepare sodium silicate solution product.

9. The method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide slag (a byproduct of acetylene production via calcium carbide hydrolysis) as described in claim 8, characterized in that... In step (5), the reaction is carried out under a water bath at 60~80℃ for 1.5~2.5 hours to prepare sodium silicate solution product.

10. The method for extracting an alkaline solution from sodium silicate waste sludge and calcium carbide slag (a byproduct of acetylene production via calcium carbide hydrolysis) as described in claim 8, characterized in that... In step (5), the mass ratio of the residue dry powder to the alkali mud powder raw material in step (1) is 1~1.5:20.

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