All-solid waste self-foaming gel and concrete based on papermaking black liquid and preparation method of all-solid waste self-foaming gel and concrete

Abstract

The invention relates to the technical field of resource utilization of industrial solid waste and papermaking waste liquid in the field of building materials, in particular to full-solid-waste self-foaming gel and concrete based on papermaking black liquid and a preparation method of the full-solid-waste self-foaming gel and concrete. According to the specific technical scheme, the full-solid waste self-foaming gel based on the papermaking black liquid and the concrete are characterized in that the self-foaming gel is prepared from the papermaking black liquid, fly ash, desulfurized gypsum, carbide slag, slag powder and steel slag powder; the concrete comprises the following components: papermaking black liquor, fly ash, slag powder, desulfurized gypsum and cement. The mechanical property of the prepared self-foaming gel is similar to that of common foam concrete, the self-foaming gel is completely composed of waste, foam does not need to be prepared in advance, the self-foaming gel can generate foam in the stirring process, and the prepared porous gel material is uniform in pore diameter.

Description

Technical Field

[0001] The present invention relates to the technical field of resource utilization of industrial solid waste and papermaking waste liquor in the field of building materials, and in particular to a full-solid waste self-foaming gel and concrete based on papermaking black liquor and a preparation method thereof. Background Art

[0002] During the papermaking process, plant fiber raw materials are cooked using either the caustic soda or sulfate process, producing a large amount of black liquor. This liquor contains significant amounts of alkali, lignin, sodium sulfate, sodium carbonate, and sodium silicate, and direct discharge into water can cause severe pollution. my country boasts a large number of small and medium-sized paper mills, but these small mills often lack black liquor recovery and utilization equipment due to resource and technical constraints. This makes the resulting black liquor difficult to treat and causes environmental pollution. Therefore, there is an urgent need for lower-cost technical solutions to treat black liquor in small and medium-sized paper mills. Because black liquor is rich in surfactants and prone to foaming, the alkali, sodium sulfate, sodium carbonate, and sodium silicate within it stimulate the chemical activity of industrial solid waste, and there is currently a significant amount of industrial solid waste that requires treatment.

[0003] Existing patents for the resource utilization of papermaking black liquor (application numbers CN202010997524.8, CN201210237304.0, CN99109815.3, and CN201811366262.4) demonstrate complex treatment processes, primarily focused on alkali recovery and the preparation of lignin-related active agents. These processes are primarily designed to address pollution, but the cost of maintaining these processes may outweigh the benefits. Furthermore, there is a lack of technologies and processes for directly using papermaking black liquor in building materials production.

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

[0005] In the existing foam concrete patents (application numbers CN202411030760.7, CN201810583025.7, CN202111571579.3) that do not add external foam and rely solely on 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 relatively low additional effects.

[0006] In the existing all-solid waste foam concrete (application numbers are CN202310598508.5, CN202111571579.3, CN202110046053.7), the raw materials are not completely waste and still require substances such as foaming agents.

[0007] Therefore, the present invention combines the material properties of papermaking black liquor and various types of industrial solid waste, and proposes a full-solid waste self-foaming gel and high-fluidity concrete based on papermaking black liquor and their preparation methods, which are used to assist in the disposal of papermaking black liquor and industrial solid waste, and create building materials with economic value. Summary of the Invention

[0008] In view of the deficiencies in the prior art, the present invention provides a self-foaming gel and concrete made from all-solid waste based on papermaking black liquor and a preparation method thereof.

[0009] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0010] The invention discloses a self-foaming gel and concrete made from all solid waste based on papermaking black liquor. The components of the self-foaming gel include: papermaking black liquor, fly ash, desulfurized gypsum, carbide slag, slag powder, and steel slag powder.

[0011] The components of the concrete include: papermaking black liquor, fly ash, slag powder, desulfurized gypsum and cement.

[0012] Preferably, the components of the self-foaming gel include, by weight, 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 in a total mass ratio of 0.4-0.6 to the powder.

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

[0014] Accordingly, the method for preparing the all-solid waste self-foaming gel and concrete based on papermaking black liquor comprises the following steps:

[0015] (1) solid-liquid separation of papermaking black liquor to separate waste liquid and waste residue, and further dehydrating the waste residue by squeezing and then drying;

[0016] (2) Mix the self-foaming gel or concrete powder evenly and keep it in a high temperature environment for 0.5-1h;

[0017] (3) mixing the high-temperature activated mixed powder with the filtered papermaking black liquor and stirring them thoroughly;

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

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

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

[0021] Preferably, in step (3), when preparing the self-foaming gel, the mixed powder activated at 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 high-temperature activated mixed powder and the filtered papermaking black liquor are mixed 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 processing it. Furthermore, it leverages the high alkalinity of papermaking black liquor and its presence of sodium sulfate, sodium carbonate, and sodium silicate to stimulate the hydration of industrial solid waste and improve the fluidity of cement slurry. Furthermore, it fully utilizes the characteristics of various materials, recycling various waste materials while not only protecting the ecological environment but also creating more economically efficient products.

[0025] 2. This invention directly utilizes papermaking black liquor in the production of building materials, not only directly reducing papermaking black liquor storage volume but also absorbing industrial solid wastes such as fly ash, carbide slag, slag powder, desulfurized gypsum, and steel slag powder, offering significant advantages in protecting the ecological environment. Furthermore, this invention fully utilizes the chemical properties of papermaking black liquor, leveraging its rich surfactant content to form foams within the gel material. 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 of the all-solid waste self-foaming gel prepared by the present invention are waste materials, and there is no need to use additional foaming agents to prepare foam in advance, which reduces the difficulty of the preparation process.

[0027] 4. The density of the self-foaming gel prepared by the present invention is in the range of 0.9-1.3g / cm 3Strength is primarily related to the silicate content of steel slag powder. The higher the silicate content and the greater the proportion of silicate in the slag powder, the stronger the mechanical properties of the resulting gel material. The addition of fly ash reduces the hydration rate, necessitating high-temperature curing to ensure improved strength later on. The all-solid waste self-foaming gel is more yellowish than conventional foam concrete and has a woody aroma.

[0028] 5. The mechanical properties of the self-foaming gel prepared by the present invention are similar to those of ordinary foam concrete. It is completely composed of waste materials and does not require the preparation of foam in advance. It will generate foam during the stirring process, and the pore size of the prepared porous gel material is relatively uniform. The prepared high-fluidity solid waste concrete has relatively low early strength, and its later strength is similar to that of conventional concrete. It has good fluidity and can reduce the amount of cement and water reducer in concrete. In the treatment of papermaking black liquor, the present invention provides a relatively simple and novel technical idea for small and medium-sized paper mills that do not have papermaking black liquor recovery technology, achieving the goal of consuming papermaking black liquor and absorbing industrial solid waste. While protecting the environment, it can produce products that meet social needs and have economic benefits, and help the upgrading and transformation of the papermaking industry.

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

[0030] 7. The present 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 and produce building materials with more economic value. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0033] Figure 3 This is the gel test piece of Example 3;

[0034] Figure 4 This is the concrete test block of Example 5;

[0035] Figure 5 This is the concrete test block of Example 6. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

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

[0038] The invention discloses a full-solid waste 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; in parts 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 desulfurization gypsum, 15-40 parts of steel slag powder, and a total mass ratio of papermaking black liquor to powder of 0.4-0.6.

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

[0040] The powder refers to the components other than 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 secondary fly ash.

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

[0042] During the concrete preparation process, a certain amount of red mud can be added to produce red concrete bricks.

[0043] The present invention also discloses a method for preparing a self-foaming gel and concrete from all-solid waste based on papermaking black liquor, comprising the following steps:

[0044] (1) solid-liquid separation of papermaking black liquor to separate waste liquid and waste residue, and further dehydrating the waste residue by squeezing and then drying;

[0045] (2) After the self-foaming gel or concrete powder is evenly mixed, the mixture is kept warm in a high temperature environment for 0.5-1 hour; the high temperature environment is 70-90°C. When producing self-foaming gel, when the silicate content in the steel slag powder is high and the amount used is large, normal room temperature curing is used; when the fly ash content is high, high temperature curing is used, the curing temperature is 50-70°C, the curing time is 3-7 days, and the humidity is ≥95%.

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

[0047] (4) Pour the stirred slurry into a mold and select a suitable curing environment according to the mix ratio for curing. When preparing self-foaming gel, 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.

[0048] The present invention uses crop straw and the waste residue dried in step (1) as fuel, and adopts a biomass boiler to create a high-temperature environment for stimulating the chemical activity of industrial solid waste, drying the waste residue and performing high-temperature curing.

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

[0050] Example 1

[0051] Preparation of self-foaming gel, the preparation process is as follows:

[0052] (1) The papermaking black liquor is subjected to solid-liquid separation to separate the waste liquid and waste residue, and 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 for stimulating the chemical activity of industrial solid waste, drying waste residue, and high-temperature maintenance.

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

[0055] (4) 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 surfactant 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 for curing. When the silicate content in the 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, the curing temperature is 50-70℃, the time is 3 days, and the humidity is ≥95%.

[0057] Example 2

[0058] The self-foaming gel was prepared according to the method of Example 1. The ratio of the all-solid waste self-foaming gel was 4:4:2 (w / w): steel slag powder: slag powder: desulfurized gypsum. The water-cement ratio of the gel to the papermaking black liquor was 0.4. The powders were mixed and 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%. The concrete test blocks after standard curing were shown in Figure 2. Figure 2 As shown, the density of the test block is 1.17 g / cm 3 , 28-day compressive strength is 7.6MPa, 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 method of Example 1. The ratio of the all-solid waste self-foaming gel was 4:3:1:1:1 (w / w). The water-cement ratio of the gel to the papermaking black liquor was 0.4. The powders were mixed and 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%. The concrete test blocks after standard curing were shown in Figure 2. Figure 3 As shown, the density of the test block is 0.95g / cm 3 , 28-day compressive strength is 5.8MPa, the foam pore size is uniform, and the test piece also has a slight woody aroma.

[0061] Example 4

[0062] The preparation process of high-fluidity solid waste concrete is as follows:

[0063] (1) The papermaking black liquor is subjected to solid-liquid separation to separate the waste liquid and waste residue, and 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 for stimulating the chemical activity of industrial solid waste, drying waste residue, and high-temperature maintenance.

[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°C for 0.5-1 hour.

[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 may be added and stirred thoroughly. During the stirring process, the surfactant in the black liquor and the alkaline environment will enhance the fluidity of the slurry. Within a certain range, the stronger the alkalinity of the black liquor, the better the slurry fluidity.

[0067] (5) A certain proportion of fine aggregate and coarse aggregate can be added to the evenly stirred slurry (according to actual needs), and after further stirring, it is poured into the mold and cured in a high temperature environment. When the water-cement ratio is relatively low, the aggregate needs to be soaked to allow it to absorb a certain amount of water, and then mixed and stirred after the surface is air-dried.

[0068] Example 5

[0069] High-fluidity solid waste concrete was prepared according to the method of Example 4. The mix ratio was: 425 Portland cement: slag powder: desulfurized gypsum: fly ash = 4:4:1:1, w / w; the water-cement ratio to papermaking black liquor was 0.38, and standard sand (twice the weight of the powder) was added. After mixing, the powders were stored at 80°C for 1 hour. The papermaking black liquor was obtained in the laboratory using the caustic soda method, with the caustic soda dosage being 2%.

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

[0071] Example 6

[0072] High-fluidity solid waste concrete was prepared according to the method of Example 4. The mix ratio was 425 Portland 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 standard sand was added, twice the weight of the powder. After mixing, the powders were stored at 80°C for 1 hour. The papermaking black liquor was prepared in the laboratory using the caustic soda method, with the caustic soda dosage being 2%.

[0073] The test blocks after curing Figure 5 As shown in the figure, the hydration rate increases with the increase in cement content, and the retarding effect of papermaking black liquor still exists, with the 28-day strength reaching 45.1 MPa. Compared with Example 3, the alkalinity in the slurry is enhanced, causing the surface of the test block to turn white.

[0074] In the preparation of high-flowability solid waste concrete, due to the strong alkalinity of papermaking black liquor, the alkalinity of the slurry increases with increasing cement content. If the slag powder and fly ash content is low, shrinkage cracking and cracking may occur in the test blocks during mid-curing, leading to performance degradation. Therefore, when designing the mix ratio, it is necessary to use materials with low hydration activity to control the hydration rate. If coarse aggregate is needed in the case of a low water-cement ratio, it should be soaked and air-dried before use. High-absorbency, porous, high-strength aggregate is more suitable for the mix design of this invention.

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

Claims

1. A self-foaming gel and concrete made from all-solid waste using papermaking black liquor, characterized by: 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.

2. The all-solid waste self-foaming gel and concrete based on papermaking black liquor according to claim 1, characterized in that: In terms of weight, the components of the self-foaming gel include: 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 total mass ratio of 0.4-0.6 to the powder.

3. The all-solid waste self-foaming gel and concrete based on papermaking black liquor according to claim 1, characterized in that: The components of the concrete include, by weight, 30-40 parts of slag powder, 10-20 parts of fly ash, 0-20 parts of desulfurized gypsum, 40-60 parts of cement, and papermaking black liquor in a total mass ratio of 0.3-0.6 to the powder.

4. The method for preparing the all-solid waste self-foaming gel and concrete based on papermaking black liquor according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) solid-liquid separation of papermaking black liquor to separate waste liquid and waste residue, and further dehydrating the waste residue by squeezing and then drying; (2) Mix the self-foaming gel or concrete powder evenly and keep it in a high temperature environment for 0.5-1h; (3) mixing the high-temperature activated mixed powder with the filtered papermaking black liquor and stirring them thoroughly; (4) Pour the stirred slurry into the mold and cure it.

5. The preparation method according to claim 4, characterized in that: In step (2), the high temperature environment is 70-90°C.

6. The preparation method according to claim 4, characterized in that: In step (2), when producing the self-foaming gel, when the silicate content in the steel slag powder is high and the amount used is large, normal room temperature curing is adopted; when the fly ash content is high, high temperature curing is adopted, the curing temperature is 50-70°C, the time is 3-7 days, and the humidity is ≥95%.

7. The preparation method according to claim 4, characterized in that: In step (3), when preparing the self-foaming gel, the mixed powder activated at high temperature is mixed with the filtered papermaking black liquor at a water-cement ratio of 0.4-0.6 and stirred thoroughly.

8. The preparation method according to claim 4, characterized in that: In step (3), 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.

Images