All-solid-waste self-foaming gel and concrete based on papermaking black liquor and method for preparing same

Abstract

This invention relates to the field of resource utilization technology for industrial solid waste and papermaking wastewater in the building materials industry, specifically to a self-foaming gel and concrete based on papermaking black liquor and its preparation method. The specific technical solution is as follows: a self-foaming gel and concrete based on papermaking black liquor, wherein the components of the self-foaming gel include: papermaking black liquor, fly ash, desulfurized gypsum, carbide slag, slag powder, and steel slag powder; the components of the concrete include: papermaking black liquor, fly ash, slag powder, desulfurized gypsum, and cement. The mechanical properties of the self-foaming gel prepared by this invention are similar to those of ordinary foamed concrete. It is composed entirely of waste materials, does not require pre-prepared foam, and generates foam during the mixing process itself. Furthermore, the prepared porous gel material has a relatively uniform pore size.

Description

Technical Field

[0001] This invention relates to the field of resource utilization technology of industrial solid waste and papermaking waste liquid in the building materials industry, specifically to a self-foaming gel and concrete based on papermaking black liquor and its preparation method. Background Technology

[0002] In the papermaking process, plant fiber raw materials produce a large amount of black liquor after being cooked using the caustic soda or sulfate process. Black liquor contains high levels of alkali, lignin, sodium sulfate, sodium carbonate, sodium silicate, and other substances, and its direct discharge into waterways causes severe pollution. my country has a large number of small and medium-sized paper mills, which often lack black liquor recovery and utilization equipment due to resource and technological limitations, making the generated black liquor difficult to treat and causing environmental pollution. Therefore, there is an urgent need for lower-cost technological solutions to help small and medium-sized paper mills treat black liquor. Because black liquor is rich in surfactants and easily produces foam, the alkali, sodium sulfate, sodium carbonate, and sodium silicate within it can activate the chemical activity of industrial solid waste, and there is currently a large amount of industrial solid waste that needs treatment.

[0003] In existing patents for the resource utilization of papermaking black liquor (application numbers CN202010997524.8, CN201210237304.0, CN99109815.3, CN201811366262.4), the treatment processes are relatively complex, mainly focusing on alkali recovery and the preparation of lignin-related activators. The primary purpose is to solve pollution problems, and the cost of maintaining the treatment process may exceed the recovery benefits. At the same time, there is a lack of relevant technologies for the direct use of papermaking black liquor in building material production.

[0004] The vast majority of existing patents related to foamed concrete (application numbers CN202110651560.3, CN201710183061.X, CN202310598508.5, CN201810543030.5) require the use of a foaming agent to first prepare foam, and then mix the foam into a gel slurry to prepare foamed concrete, which is a relatively complex preparation process.

[0005] In existing foamed concrete patents (application numbers CN202411030760.7, CN201810583025.7, CN202111571579.3) that do not require external foaming and rely solely on the self-foaming of raw materials, materials such as cellulose ether, sodium perborate, electrolytic manganese slag, and aluminum powder are used. These materials mainly play a foaming role and have low additional effects.

[0006] In existing solid waste foamed concrete (application numbers CN202310598508.5, CN202111571579.3, CN202110046053.7), the raw materials are not entirely waste materials, and foaming agents and other substances are still required.

[0007] Therefore, this invention combines the material properties of papermaking black liquor and various industrial solid wastes to propose a self-foaming gel and high-flowability concrete based on papermaking black liquor, and their preparation methods, to assist in the disposal of papermaking black liquor and industrial solid waste, and to create building materials with economic value. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a self-foaming gel and concrete based on papermaking black liquor, and a method for preparing the same.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] This invention discloses a self-foaming gel and concrete based on papermaking black liquor, wherein the components of the self-foaming gel include: papermaking black liquor, fly ash, desulfurization gypsum, carbide slag, slag powder, and steel slag powder.

[0011] The concrete comprises: black liquor from papermaking, fly ash, slag powder, desulfurized gypsum, and cement.

[0012] Preferably, the self-foaming gel comprises, by weight, 0-10 parts fly ash, 0-10 parts carbide slag powder, 30-40 parts slag powder, 10-20 parts desulfurized gypsum, 15-40 parts steel slag powder, and papermaking black liquor in a mass ratio of 0.4-0.6 to the total powder.

[0013] Preferably, the concrete composition, by weight, includes: 30-40 parts slag powder, 10-20 parts fly ash, 0-20 parts desulfurized gypsum, 40-60 parts cement, and papermaking black liquor in a mass ratio of 0.3-0.6 to the total powder.

[0014] Correspondingly, the preparation methods of self-foaming gel and concrete based on papermaking black liquor include the following steps:

[0015] (1) Solid-liquid separation is performed on the black liquor of papermaking to separate waste liquid and waste residue. The waste residue is further dehydrated by extrusion and then dried.

[0016] (2) After mixing the self-foaming gel or concrete powder evenly, keep it at a high temperature for 0.5-1h;

[0017] (3) Mix the high-temperature activated powder with the filtered papermaking black liquor and stir thoroughly;

[0018] (4) Pour the mixed slurry into the mold and cure it.

[0019] Preferably, in step (2), the high-temperature environment is 70-90℃.

[0020] Preferably, in step (2), when producing self-foaming gel, if the silicate content in the steel slag powder is high and the amount is large, normal room temperature curing is used; if the fly ash content is high, high temperature curing is used, with a curing temperature of 50-70℃, a time of 3-7 days, and a humidity of ≥95%.

[0021] Preferably, in step (3), when preparing the self-foaming gel, the mixed powder activated by high temperature is mixed with the filtered papermaking black liquor at a water-cement ratio of 0.4-0.6 and stirred thoroughly.

[0022] Preferably, in step (3), when preparing concrete, the mixed powder activated by high temperature is mixed with the filtered papermaking black liquor at a water-cement ratio of 0.3-0.6 and stirred thoroughly.

[0023] The present invention has the following beneficial effects:

[0024] 1. This invention fully utilizes the chemical properties of papermaking black liquor, combining it with the preparation of building materials to reduce the difficulty of treating papermaking black liquor. Simultaneously, it leverages the high alkalinity of papermaking black liquor and its presence of sodium sulfate, sodium carbonate, sodium silicate, etc., to stimulate the hydration activity of industrial solid waste and improve the fluidity of cement slurry. Furthermore, by fully utilizing the characteristics of various materials, it not only protects the ecological environment but also creates more economically efficient products while recycling various waste materials.

[0025] 2. This invention directly uses papermaking black liquor in the production of building materials, which not only directly reduces the amount of papermaking black liquor stored, but also facilitates the disposal of industrial solid wastes such as fly ash, carbide slag, slag powder, desulfurization gypsum, and steel slag powder, demonstrating a strong advantage in protecting the ecological environment. Simultaneously, it fully utilizes the chemical properties of papermaking black liquor, leveraging its rich content of surfactants for foaming in gel materials. Its high alkalinity and the presence of sodium sulfate, sodium silicate, and sodium carbonate stimulate the pozzolanic activity of industrial solid wastes such as slag, fly ash, and steel slag, promoting the formation of hydrated gels.

[0026] 3. All raw materials used in the self-foaming gel prepared from solid waste in this invention are waste materials, eliminating the need for additional foaming agents to prepare foam in advance, thus reducing the difficulty of the preparation process.

[0027] 4. The density range of the self-foaming gel made from solid waste prepared in this invention is 0.9-1.3 g / cm³. 3The strength is mainly related to the silicate content in the steel slag powder; the higher the content and the greater the proportion, the stronger the mechanical properties of the prepared gel material. Adding fly ash reduces the hydration rate, requiring high-temperature curing to ensure better later-stage strength. The color of the all-solid-waste self-foaming gel is more yellowish than ordinary foamed concrete, and it has a woody aroma.

[0028] 5. The self-foaming gel prepared by this invention has mechanical properties similar to ordinary foamed concrete. It is entirely composed of waste materials, eliminating the need for pre-prepared foam, as foam is generated during the mixing process. Furthermore, the prepared porous gel material exhibits relatively uniform pore size. The prepared high-flowability solid waste concrete has relatively low early-stage strength, but its later-stage strength is similar to conventional concrete. It also possesses excellent flowability, reducing the amount of cement and water-reducing agents required in concrete. Regarding the treatment of papermaking black liquor, this invention provides a relatively simple and novel technical approach for small and medium-sized paper mills lacking black liquor recycling technology. It achieves the goal of both consuming papermaking black liquor and disposing of industrial solid waste, protecting the environment while producing products that meet social needs and have economic benefits, and contributing to the upgrading and transformation of the papermaking industry.

[0029] 6. In the high-flowability solid waste concrete prepared by this invention, the dissolution of papermaking black liquor and cement is sufficient to activate the hydration activity of industrial solid waste, which can reduce the demand for cement and reduce production costs.

[0030] 7. This invention combines the treatment of papermaking black liquor with the preparation of building materials, which can reduce the difficulty of treating papermaking black liquor to a certain extent, while producing building materials with greater economic value. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the present invention;

[0032] Figure 2 This is the gel test block from Example 2;

[0033] Figure 3 This is the gel test block from Example 3;

[0034] Figure 4 This refers to the concrete test block used in Example 5;

[0035] Figure 5 This is a concrete test block from Example 6. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Unless otherwise specified, the technical means used in the implementation examples are conventional means well known to those skilled in the art.

[0038] This invention discloses a self-foaming gel and concrete based on papermaking black liquor, wherein the components of the self-foaming gel include: papermaking black liquor, fly ash, desulfurized gypsum, carbide slag, slag powder, and steel slag powder; by weight, the self-foaming gel includes: 0-10 parts of fly ash, 0-10 parts of carbide slag powder, 30-40 parts of slag powder, 10-20 parts of desulfurized gypsum, 15-40 parts of steel slag powder, and papermaking black liquor with a mass ratio of 0.4-0.6 to the total powder.

[0039] The concrete comprises: papermaking black liquor, fly ash, slag powder, desulfurized gypsum, and cement. By weight, the concrete comprises: 30-40 parts slag powder, 10-20 parts fly ash, 0-20 parts desulfurized gypsum, 40-60 parts cement, and papermaking black liquor at a mass ratio of 0.3-0.6 to the total powder.

[0040] Among them, powder refers to other components besides papermaking black liquor. The slag powder is S105 slag powder, the desulfurized gypsum is 300 mesh, the steel slag powder is 300 mesh, and the fly ash is grade II fly ash.

[0041] Furthermore, as another implementation method, in the preparation process of self-foaming gel, materials such as papermaking mud, shell powder, and oyster powder can be calcined at high temperature to replace carbide slag powder.

[0042] A certain amount of red mud can be added during the concrete preparation process to produce red concrete bricks.

[0043] This invention also discloses a method for preparing self-foaming gel and concrete based on papermaking black liquor, comprising the following steps:

[0044] (1) Solid-liquid separation is performed on the black liquor of papermaking to separate waste liquid and waste residue. The waste residue is further dehydrated by extrusion and then dried.

[0045] (2) After uniformly mixing the self-foaming gel or concrete powder, keep it at a high temperature for 0.5-1 hour; the high temperature environment is 70-90℃. When producing self-foaming gel, if the silicate content in the steel slag powder is high and the amount used is large, normal room temperature curing is used; if the fly ash content is high, high temperature curing is used, with a curing temperature of 50-70℃, a time of 3-7 days, and a humidity ≥95%.

[0046] (3) The high-temperature activated mixed powder is mixed with the filtered papermaking black liquor and stirred thoroughly. Specifically: when preparing self-foaming gel, the high-temperature activated mixed powder is mixed with the filtered papermaking black liquor at a water-cement ratio of 0.4-0.6 and stirred thoroughly. During the stirring process, the surface-active substances in the black liquor will play a foaming role. When preparing concrete, the high-temperature activated mixed powder is mixed with the filtered papermaking black liquor at a water-cement ratio of 0.3-0.6 and stirred thoroughly.

[0047] (4) Pour the mixed slurry into the mold and select a suitable curing environment according to the mixing ratio. When preparing self-foaming gel, if the silicate content in the steel slag powder is high and the amount is large, normal room temperature curing is used; if the fly ash content is high, high temperature curing is used.

[0048] This invention uses crop straw and the waste residue dried in step (1) as fuel, and uses a biomass boiler to create a high-temperature environment to stimulate the chemical activity of industrial solid waste, dry the waste residue, and perform high-temperature curing.

[0049] The present invention will be further described below with reference to specific embodiments.

[0050] Example 1

[0051] The preparation process of self-foaming gel is as follows:

[0052] (1) Solid-liquid separation is performed on the black liquor of papermaking to separate waste liquid and waste residue. The waste residue is further dehydrated by squeezing and then dried.

[0053] (2) Using crop straw and dried waste residue as fuel, a biomass boiler is used to create a high-temperature environment to stimulate the chemical activity of industrial solid waste, dry the waste residue, and perform high-temperature curing.

[0054] (3) Mix 300 mesh steel slag powder, S105 slag powder, 300 mesh desulfurized gypsum, calcium carbide slag powder and secondary fly ash evenly and keep warm at 70-90℃ for 0.5-1h.

[0055] (4) The mixed powder activated by high temperature is mixed with the filtered papermaking black liquor at a water-ash ratio of 0.4-0.6 and stirred thoroughly. During the stirring process, the surface active substances in the black liquor will play a foaming role.

[0056] (5) Pour the mixed slurry into the mold and select a suitable curing environment according to the mix ratio. When the silicate content in the steel slag powder is high and the amount is large, normal room temperature curing is used; when the fly ash content is high, high temperature curing is used, with a curing temperature of 50-70℃, a time of 3 days, and a humidity of ≥95%.

[0057] Example 2

[0058] The self-foaming gel was prepared according to the preparation method in Example 1. The ratio of the solid waste self-foaming gel was: steel slag powder: blast furnace slag powder: desulfurized gypsum = 4:4:2, w / w, with a water-cement ratio of 0.4 to the papermaking black liquor. After mixing the powders, the mixture was stored at 80°C for 1 hour. The papermaking black liquor was prepared in the laboratory using the caustic soda method, with an alkali dosage of 2%. See the sample block after standard curing of the concrete. Figure 2 As shown, the density of the sample block is 1.17 g / cm³. 3 The compressive strength after 28 days is 7.6 MPa, the foam pore size is uniform, and the test block has a slight woody aroma.

[0059] Example 3

[0060] The self-foaming gel was prepared according to the preparation method in Example 1. The ratio of the solid waste self-foaming gel was: steel slag powder: blast furnace slag powder: desulfurized gypsum: carbide slag: fly ash = 4:3:1:1:1, w / w; the water-ash ratio with papermaking black liquor was 0.4. After mixing the powders, the mixture was stored at 80°C for 1 hour. The papermaking black liquor was prepared in the laboratory using the caustic soda method, with an alkali dosage of 2%. See the standard cured concrete test block for example. Figure 3 As shown, the density of the test block is 0.95 g / cm³. 3 The compressive strength after 28 days is 5.8 MPa, the foam pore size is uniform, and the test block also has a slight woody aroma.

[0061] Example 4

[0062] The preparation process of highly fluid solid waste concrete is as follows:

[0063] (1) Solid-liquid separation is performed on the black liquor of papermaking to separate waste liquid and waste residue. The waste residue is further dehydrated by squeezing and then dried.

[0064] (2) Using crop straw and dried waste residue as fuel, a biomass boiler is used to create a high-temperature environment to stimulate the chemical activity of industrial solid waste, dry the waste residue, and perform high-temperature curing.

[0065] (3) 30-40 parts of S105 slag powder, 1-20 parts of 300 mesh desulfurized gypsum, 10-20 parts of secondary fly ash, and 40-60 parts of cement. Mix all the powders evenly and keep them at 70-90℃ for 0.5-1h.

[0066] (4) The high-temperature activated mixed powder is mixed with the filtered papermaking black liquor at a water-cement ratio of 0.3-0.6. An appropriate amount of defoamer can be added and the mixture is stirred thoroughly. During the stirring process, the surface-active substances and alkaline environment in the black liquor will enhance the fluidity of the pulp. Within a certain range, the stronger the alkalinity of the black liquor, the better the fluidity of the pulp.

[0067] (5) A certain proportion of fine and coarse aggregates can be added to the well-mixed cement paste (add as needed), and after further mixing, it is poured into the mold and cured in a high-temperature environment. When the water-cement ratio is low, the aggregates need to be soaked to absorb a certain amount of water, and then mixed after the surface is air-dried.

[0068] Example 5

[0069] The high-flowability solid waste concrete was prepared according to the preparation method in Example 4. The mix proportion was: 425 silicate cement: slag powder: desulfurized gypsum: fly ash = 4:4:1:1, w / w; the water-cement ratio with papermaking black liquor was 0.38, and two times the mass of standard sand was added. After mixing, the powder was stored at 80°C for 1 hour. The papermaking black liquor was prepared in the laboratory using the caustic soda method, with an alkali dosage of 2%.

[0070] See the test blocks after standard curing of concrete. Figure 4 As shown, the fluidity of the paste without aggregate is higher than that of silicate cement at the same water-cement ratio, and similar to that of cement paste with 0.2% dry powder polycarboxylate superplasticizer. The early hydration rate is lower than that of silicate cement, and some organic matter in the papermaking black liquor has a retarding effect. The strength is extremely low in the first 3 days at room temperature, and the 28-day strength rate is lower than that of 425 silicate cement sample, which can reach 32.7 MPa.

[0071] Example 6

[0072] The high-flowability solid waste concrete was prepared according to the preparation method in Example 4. The mix proportion was: 425 silicate cement: slag powder: desulfurized gypsum: fly ash = 6:2:1:1, w / w; the water-cement ratio with papermaking black liquor was 0.38, and two times the mass of standard sand was added. After mixing, the powder was stored at 80°C for 1 hour. The papermaking black liquor was prepared in the laboratory using the caustic soda method, with an alkali dosage of 2%.

[0073] See the test block after curing Figure 5 As shown, the hydration rate increases with increasing cement content, but the retarding effect of the papermaking black liquor still exists, and the 28-day strength can reach 45.1 MPa. Compared to Example 3, the alkalinity in the pulp is enhanced, causing the surface of the test block to turn white.

[0074] In the preparation of high-fluidity solid waste concrete, due to the strong alkalinity of papermaking black liquor, the alkalinity of the slurry increases with the increase of cement content. If the content of slag powder and fly ash is low at this time, shrinkage cracking will occur in the test blocks during the curing period, leading to a decline in performance. Therefore, in the mix design, it is necessary to use substances with low hydration activity to restrain the hydration rate. When the water-cement ratio is low, if coarse aggregate needs to be added, it needs to be soaked and air-dried before use. Porous, high-strength aggregates with strong water absorption are more suitable for the mix design of this invention.

[0075] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A full solid waste self-foaming gel based on papermaking black liquor, characterized in that: The self-foaming gel comprises: papermaking black liquor, fly ash, desulfurized gypsum, carbide slag, slag powder, and steel slag powder; by weight, the self-foaming gel comprises: 0-10 parts fly ash, 0-10 parts carbide slag powder, 30-40 parts slag powder, 10-20 parts desulfurized gypsum, 15-40 parts steel slag powder, and papermaking black liquor with a mass ratio of 0.4-0.6 to the total powder; the powder refers to other components besides the papermaking black liquor.

2. The process for the preparation of a full solid waste self-foaming gel based on papermaking black liquor according to claim 1, characterized by the fact that: Includes the following steps: (1) Solid-liquid separation is performed on the black liquor of papermaking to separate waste liquid and waste residue. The waste residue is further dehydrated by squeezing and then dried. (2) After mixing the self-foaming gel powder evenly, keep it at a high temperature for 0.5-1h; the high temperature environment is 70-90℃; (3) Mix the high-temperature activated powder with the filtered papermaking black liquor and stir thoroughly; (4) Pour the mixed slurry into the mold and cure it. When the silicate content in the steel slag powder is high and the amount is large, cure it at normal room temperature. When the fly ash content is high, use high temperature curing. The curing temperature is 50-70℃, the time is 3-7 days, and the humidity is ≥95%.

3. The method of claim 2, wherein: In step (3), the mixed powder activated at high temperature is mixed with the filtered black liquor of papermaking at a water-ash ratio of 0.4-0.6 and stirred thoroughly.

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