Electrolytic manganese residue and hydrogen peroxide synergistic foamed lightweight porous ceramsite and preparation method thereof

Abstract

The application discloses a kind of electrolytic manganese residue and hydrogen peroxide foaming light porous haydite and preparation method.The application includes the following raw materials by weight parts: electrolytic manganese residue: 40-45 parts, slag: 18-20 parts, hydrogen peroxide: 1-6 parts, foam stabilizer: 0.04-0.07 parts, coagulant: 0.2-0.5 parts, water: 30-32 parts.The application utilizes MnO2 component in electrolytic manganese residue to catalyze the decomposition of hydrogen peroxide in hydrogen peroxide, and the O2 generated by the reaction of the two can provide enough pores for haydite to achieve the purpose of light and porous, providing a new direction for the resource utilization of electrolytic manganese residue.Moreover, the application uses solid waste slag and heavy metal pollutants electrolytic manganese residue as cementing component to prepare unburned light and porous haydite, greatly solving the problems of high preparation cost, complex process, unstable product performance and the like of porous haydite.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a lightweight porous ceramsite with electrolytic manganese slag synergistically foamed with hydrogen peroxide and its preparation method. Background Technology

[0002] Electrolytic manganese slag is the acid leaching waste generated during the preparation of manganese sulfate solution from rhodochrosite using sulfuric acid. Due to its low value, high soluble salt content, and complex composition, there is currently no mature comprehensive utilization technology. Enterprises typically use wet storage methods for disposal, which not only occupies land but also causes significant environmental pollution and safety risks. Because of its low added value from comprehensive utilization, the use of manganese slag in building materials has become a research hotspot in the manganese industry and environmental protection field. However, due to the low activity, fine particle size, complex composition and phases, and high water-soluble sulfate content of manganese acid leaching slag, its incorporation into building materials is low, and its quality is difficult to meet requirements, making it unacceptable to the market. Therefore, realizing the resource utilization of electrolytic manganese slag has become a key research and development issue for many building material manufacturers and technicians. Summary of the Invention

[0003] In view of this, the present invention aims to provide a lightweight porous ceramsite synergistic with hydrogen peroxide foaming of electrolytic manganese slag, in order to solve the problem of the difficulty in resource utilization of existing electrolytic manganese slag.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] A lightweight porous ceramsite foamed with electrolytic manganese slag and hydrogen peroxide, comprising the following raw materials by weight: electrolytic manganese slag: 40-45 parts, slag soil: 18-20 parts, hydrogen peroxide: 1-6 parts, foam stabilizer: 0.04-0.07 parts, coagulant accelerator: 0.2-0.5 parts, and water: 30-32 parts.

[0006] Optionally, the electrolytic manganese slag has a 200-mesh sieve pass rate of ≥90% and an MnO2 content of 18-25%.

[0007] Optionally, the slag has a 200-mesh sieve pass rate of ≥90%, a SiO2 content of 60-65%, and an Al2O3 content of 16-18%.

[0008] Optionally, the H2O2 content in the hydrogen peroxide is 25-35%.

[0009] Optionally, the foam stabilizer is one or more of xanthan gum, hydroxymethyl cellulose ether, and calcium stearate.

[0010] Optionally, the coagulant is one or both of sodium aluminate and calcium thiocyanate.

[0011] The second objective of this invention is to provide a method for preparing lightweight porous ceramsite synergistically foamed with electrolytic manganese slag, the preparation method comprising the following steps:

[0012] 1) Mix the electrolytic manganese slag and the slag soil evenly to obtain mixture A;

[0013] 2) After the water and the foam stabilizer are mixed evenly, the mixture is added to the mixture A and stirred to obtain slurry B;

[0014] 3) Add the hydrogen peroxide to the slurry B, stir and foam. After foaming is complete, add the coagulant and continue stirring for a period of time to obtain slurry C;

[0015] 4) Pour the slurry C into the mold, cure it under standard conditions for a period of time, remove the mold and dry it at 50-60℃, and then cure it under standard conditions to the target age to obtain lightweight porous ceramsite with electrolytic manganese slag and hydrogen peroxide foaming.

[0016] Optionally, the stirring speed in steps 1) and 2) is 70-90 r / min, and the stirring time is 2-3 min.

[0017] Optionally, the stirring speed in step 3) is 40-50 r / min, and the stirring time is 2-3 min.

[0018] Optionally, the lightweight porous ceramsite foamed with electrolytic manganese slag and hydrogen peroxide in step 4) is spherical with a diameter of 10-15 mm.

[0019] Compared with existing technologies, the lightweight porous ceramsite with electrolytic manganese slag and hydrogen peroxide foaming described in this invention has the following advantages:

[0020] 1. This invention uses electrolytic manganese slag to prepare lightweight porous ceramsite. The MnO2 contained in the electrolytic manganese slag can catalyze the decomposition of H2O2 in hydrogen peroxide to produce gas, forming a porous structure within the ceramsite. To control the rate at which the electrolytic manganese slag catalyzes the decomposition of H2O2 in hydrogen peroxide to produce oxygen, this invention adds slag soil to adjust the slurry viscosity and pH, reducing the distribution density of the electrolytic manganese slag. This avoids an excessively fast reaction rate of H2O2 catalysis by the electrolytic manganese slag and excessively low slurry viscosity, which are detrimental to pore formation and thus affect the porosity of the resulting ceramsite. Furthermore, to further improve the stability of the pores after pore formation in the slurry, this invention adds a foam stabilizer and a coagulant to achieve the formation and stabilization of pores in stages during and after the H2O2 foaming process. Through the synergistic effect of the components, the resulting lightweight porous ceramsite foamed with electrolytic manganese slag and hydrogen peroxide exhibits excellent performance, with an apparent density of 0.43-1.87 g / cm³. 3The open porosity is 24.14-36.22%, the closed porosity is 4.21-10.22%, and the water absorption rate in 1 hour is 2.41-14.8%.

[0021] 2. When the lightweight porous ceramsite of the present invention is used to prepare foamed concrete, the water absorption rate of the foamed concrete can be controlled by means of pre-wetting, so that it can play a good internal curing role, thereby significantly improving the foam stability of the foamed concrete in the setting stage and reducing the drying shrinkage value of the foamed concrete. At the same time, thanks to the porous structure of the ceramsite itself, it not only helps the later carbonation curing of the foamed concrete to be enhanced and CO2 penetration is strengthened, but also enhances the skeleton structure and density. Its 28-day compressive strength can reach 6.21 MPa and its 28-day carbon fixation rate can reach 20.75%.

[0022] 3. This invention provides a new direction for the resource utilization of electrolytic manganese slag, and also greatly reduces the preparation cost of lightweight porous ceramsite and increases the added value of raw materials. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0024] Figure 1 This is a diagram illustrating the foam-stabilizing effect of hydroxymethyl cellulose ether, a foam stabilizer, in an embodiment of the present invention. Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solutions and effects of the present invention, several embodiments will be provided below. Obviously, the following description is only an embodiment and does not limit the scope of protection of the present invention.

[0026] In this invention, the foam-stabilizing effect of the foam stabilizer hydroxymethyl cellulose ether is as follows: Figure 1 As shown in Table 1, the coagulation effect of sodium aluminate as a coagulant is shown in Table 2, and the dosage of each raw material is shown in Table 2.

[0027] Depend on Figure 1 It can be seen that as the dosage of hydroxymethyl cellulose ether increases, its half-life gradually increases. The water exudation at 1 hour decreases first and then increases. Considering the foam stabilizing effect of hydroxymethyl cellulose ether, the optimal dosage of foam stabilizer hydroxymethyl cellulose ether is 0.15 to 0.2% of the water dosage.

[0028] As shown in Table 1, the initial setting effect becomes more and more significant as the dosage of sodium aluminate accelerator increases. Considering the characteristics of the slurry system of this invention, the optimal dosage of sodium aluminate accelerator is 1 to 1.5% of the water dosage.

[0029] Table 1

[0030]

[0031] In each embodiment of the present invention, the main performance indicators of each raw material are as follows:

[0032] The 200-mesh sieve pass rate of electrolytic manganese slag is 95%, and the MnO2 content is 20%.

[0033] The slag soil had a 200-mesh sieve pass rate of 95%, a SiO2 content of 65%, and an Al2O3 content of 18%.

[0034] The hydrogen peroxide contained 30% H2O2. Example 1

[0035] A method for preparing lightweight porous ceramsite synergistically foamed with electrolytic manganese slag and hydrogen peroxide includes the following steps:

[0036] 1) Put 200g of electrolytic manganese slag and 100g of slag into a mixing pot, and set the speed of the mixing pot to 80r / min. Dry mix for 3 minutes until the mixture is uniform to obtain mixture A.

[0037] 2) Mix 150g of water with 0.3g of foam stabilizer hydroxymethyl cellulose ether and stir evenly with a glass rod. Then slowly pour the mixture into the mixing pot of step 1) and continue stirring at 80r / min until it is evenly mixed with the mixture A to obtain slurry B.

[0038] 3) Add 6g of hydrogen peroxide (which is 2% of the total amount of electrolytic manganese slag and soil used as cementing material) to slurry B in step 2), set the stirring speed to 40r / min and start stirring and foaming. After stirring and foaming for 3 minutes, add 1.5g of coagulant sodium aluminate and continue stirring for 2 minutes to obtain slurry C.

[0039] 4) Slowly pour slurry C into the spherical mold, place it in the standard curing room for 12 hours, demold the ceramsite, and vacuum dry it in a vacuum drying oven at 50℃ for 6 hours. Then, place it in the standard curing room for 28 days to obtain lightweight porous ceramsite with a diameter of 10-15mm, which is foamed by electrolytic manganese slag and hydrogen peroxide.

[0040] Example 2

[0041] The difference between this embodiment and embodiment 1 is that the amount of hydrogen peroxide used in this embodiment is 12g, which is 4% of the total amount of electrolytic manganese slag and soil used as cementing materials. Everything else is the same as in embodiment 1. Specifically, the amount of each raw material is shown in Table 2.

[0042] Example 3

[0043] The difference between this embodiment and embodiment 1 is that the amount of hydrogen peroxide used in this embodiment is 18g, which is 6% of the total amount of electrolytic manganese slag and soil used as cementing materials. Everything else is the same as in embodiment 1. Specifically, the amount of each raw material is shown in Table 2.

[0044] Example 4

[0045] The difference between this embodiment and Embodiment 1 is that the amount of hydrogen peroxide used in this embodiment is 24g, which is 8% of the total amount of electrolytic manganese slag and soil used as cementing materials. Everything else is the same as in Embodiment 1. Specifically, the amount of each raw material is shown in Table 2.

[0046] Example 5

[0047] The difference between this embodiment and embodiment 1 is that the amount of hydrogen peroxide used in this embodiment is 30g, which is 10% of the total amount of electrolytic manganese slag and soil used as cementing materials. Everything else is the same as in embodiment 1. Specifically, the amount of each raw material is shown in Table 2.

[0048] Table 2

[0049] Comparative Example 1 200 100 150 0 1.5 0.3 Comparative Example 2 300 0 150 6 1.5 0.3 Comparative Example 3 200 100 150 6 1.5 0 Comparative Example 4 200 100 150 6 0 0.3 Example 1 200 100 150 6 1.5 0.3 Example 2 200 100 150 12 1.5 0.3 Example 3 200 100 150 18 1.5 0.3 Example 4 200 100 150 24 1.5 0.3 Example 5 200 100 150 30 1.5 0.3

[0050] The performance of the non-fired ceramsite in each embodiment was tested according to the standards GB / T 17431.1-2010 "Lightweight aggregates and their test methods (Part 1: Lightweight aggregates)" and GB / T 17431.2-2010 "Lightweight aggregates and their test methods (Part 2: Lightweight aggregate test methods)", including apparent density, open porosity, closed porosity, 1-hour water absorption rate, and mechanical properties. It was compared with Comparative Example 1 without hydrogen peroxide, Comparative Example 2 without slag, Comparative Example 3 without foam stabilizer, and Comparative Example 4 without accelerator. The raw material dosage of each comparative example is shown in Table 2, and the test results are shown in Table 3.

[0051] Table 3

[0052] Comparative Example 1 2.54 0.01 0.00 1.01 3.12 Comparative Example 2 2.07 2.11 0.45 1.19 1.27 Comparative Example 3 1.58 18.65 4.67 1.93 2.54 Comparative Example 4 1.79 15.78 4.22 1.64 2.27 Example 1 1.45 24.89 5.56 2.41 2.12 Example 2 0.94 26.11 6.99 6.75 5.12 Example 3 0.43 36.22 10.22 14.8 9.74 Example 4 1.21 29.45 7.31 8.41 8.65 Example 5 1.87 24.14 4.21 3.22 6.31

[0053] As shown in Table 3, with the addition of hydrogen peroxide, the apparent density of the lightweight porous ceramsite of the present invention first decreases and then increases, with the lowest value being 0.43 g / cm³. 3Compared to Comparative Example 1, the apparent density decreased by 83.1%. This is because the addition of hydrogen peroxide introduced air bubbles, and under the action of sodium aluminate and hydroxymethyl cellulose ether, the slurry quickly solidified, retaining the air bubbles and forming dense pores, thus reducing the density of the ceramsite. However, when the hydrogen peroxide content exceeded 6% (i.e., Example 3), on the one hand, the gas generated by the violent reaction between hydrogen peroxide and MnO2 in electrolytic manganese slag could not be fully retained inside the slurry, resulting in the loss of air bubbles. On the other hand, the violent reaction of excessive hydrogen peroxide with MnO2 caused the temperature of the slurry to rise rapidly, affecting the foam-stabilizing effect of the foam stabilizer hydroxymethyl cellulose ether, thus losing more air bubbles. At the same time, the roundness and uniformity of the air bubbles were also affected. Therefore, the apparent density of Examples 4-5 began to increase. The same pattern can be found in the porosity test and other tests. Overall, the apparent density of the obtained ceramsite was lower than that of Comparative Example 1, and the porosity was higher than that of Comparative Example 1. Moreover, when the hydrogen peroxide content exceeded 4%, the mechanical properties of the obtained ceramsite were better than those of Comparative Example 1.

[0054] Similarly, as shown in Table 3, the apparent density of the lightweight porous ceramsite of Example 1 of the present invention is significantly lower and the porosity is significantly increased compared to Comparative Example 2 without slag, while the mechanical properties are improved. This is because the addition of slag increases the pozzolanic activity and viscosity of the overall cementitious material, making the effect of the accelerator more pronounced. Compared to Comparative Example 3 without foam stabilizer and Comparative Example 4 without accelerator, the porosity of Example 1 is increased, but the mechanical properties are decreased. This is because the addition of foam stabilizer and accelerator makes the generated bubbles more stable and enables the slurry to solidify quickly, preventing bubble loss.

[0055] Application examples

[0056] The lightweight porous ceramsite of Example 3 of this invention was applied to cement paste foamed concrete at different dosages. The designed mix proportions are shown in Table 4. The foaming agent used in the preparation of the cement paste foamed concrete was a composite foaming agent consisting of 2% animal protein and 0.4% sodium α-olefin sulfonate, and the foam stabilizer was 0.6% hydroxymethyl cellulose ether. Mechanical properties, water absorption, and carbonation performance were tested according to standard JG / T266-2011 "Foamed Concrete," and compared with foamed concrete without the lightweight porous ceramsite of Example 3 of this invention. The test results are shown in Table 5.

[0057] As shown in Table 5, with the increase of the lightweight porous ceramsite content of the present invention, the 28-day strength of the foamed concrete exhibits a trend of first increasing, then increasing, and then decreasing. In Application Example 2, when the ceramsite content is 40%, the maximum value of 6.21 MPa is reached. When the content increases to 50%, the 28-day compressive strength of the foamed concrete decreases to 5.96 MPa. This may be because excessive ceramsite can cause the rupture and adsorption of foam inside the foamed concrete. The surface of the ceramsite itself is rough and cannot provide a stable adsorption interface for the foam. This situation becomes more pronounced when the ceramsite content exceeds a certain value.

[0058] As shown in Table 5, with the increase of the amount of lightweight porous ceramsite in this invention, the water absorption rate of foamed concrete in 1 hour shows a continuous increasing trend. This also explains the phenomenon that the mechanical properties of foamed concrete decrease after the amount of ceramsite exceeds a certain level. The addition of 50% non-fired ceramsite in Application 3 increases the water absorption rate inside the foamed concrete. In the early stage of molding, the non-fired ceramsite absorbs the water in the foamed concrete slurry due to its porous characteristics. The reduction of water is not conducive to the stable existence of foam and also leads to the increase of water absorption rate of foamed concrete in the later stage.

[0059] As can be seen from Table 5, with the increase of the content of lightweight porous ceramsite of the present invention, the 28-day carbon fixation rate of foamed concrete shows a trend of first increasing and then decreasing. The carbon fixation rate reaches a maximum of 20.75% when the content of ceramsite is 40%. The introduction of ceramsite optimizes the internal pore structure and provides more channels for CO2 penetration.

[0060] Table 4

[0061] Comparative Example 0 500 207 0 25 Application Example 1 30 500 207 150 26 Application Example 2 40 500 207 200 28 Application Example 3 50 500 207 250 31

[0062] Table 5

[0063]

[0064] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A non-fired lightweight porous ceramsite synergistically foamed with electrolytic manganese slag and hydrogen peroxide, characterized in that, The raw materials, by weight, include the following: electrolytic manganese slag: 40-45 parts, slag soil: 18-20 parts, hydrogen peroxide: 1-6 parts, foam stabilizer: 0.04-0.07 parts, coagulant accelerator: 0.2-0.5 parts, water: 30-32 parts. The electrolytic manganese slag has a 200-mesh sieve passing rate ≥90% and a MnO2 content of 18-25%. The slag soil has a 200-mesh sieve passing rate ≥90% and a SiO2 content of 60-65%. The Al2O3 content is 16-18%.

2. The non-fired lightweight porous ceramsite with electrolytic manganese slag and hydrogen peroxide foaming as described in claim 1, characterized in that, The hydrogen peroxide contains 25-35% H2O2.

3. The non-fired lightweight porous ceramsite with electrolytic manganese slag and hydrogen peroxide foaming as described in claim 1, characterized in that, The foam stabilizer is one or more of xanthan gum, hydroxymethyl cellulose ether, and calcium stearate.

4. The non-fired lightweight porous ceramsite with electrolytic manganese slag and hydrogen peroxide foaming as described in claim 1, characterized in that, The coagulant is one or both of sodium aluminate and calcium thiocyanate.

5. A method for preparing non-fired lightweight porous ceramsite with electrolytic manganese slag and hydrogen peroxide foaming as described in any one of claims 1 to 4, characterized in that, Includes the following steps: 1) The electrolytic manganese slag and the slag soil are stirred and mixed evenly to obtain mixture A; 2) After the water and the foam stabilizer are mixed evenly, the mixture is added to the mixture A and stirred to obtain slurry B; 3) Add the hydrogen peroxide to the slurry B, stir and foam. After foaming is complete, add the coagulant and continue stirring for a period of time to obtain slurry C; 4) Pour the slurry C into the mold, cure it under standard conditions for a period of time, remove the mold and dry it at 50-60°C, and then cure it under standard conditions to the target age to obtain non-fired lightweight porous ceramsite with electrolytic manganese slag and hydrogen peroxide foaming.

6. The method for preparing non-fired lightweight porous ceramsite synergistically foamed with electrolytic manganese slag according to claim 5, characterized in that, The stirring speed in steps 1) and 2) is 70-90 r / min, and the stirring time is 2-3 min.

7. The method for preparing non-fired lightweight porous ceramsite synergistically foamed with electrolytic manganese slag according to claim 5, characterized in that, The stirring speed in step 3) is 40-50 r / min, and the stirring time is 2-3 min.

8. The method for preparing non-fired lightweight porous ceramsite with electrolytic manganese slag and hydrogen peroxide foaming according to claim 5, characterized in that, The non-fired lightweight porous ceramsite foamed with electrolytic manganese slag and hydrogen peroxide as described in step 4) is spherical with a diameter of 10-15 mm.

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