Quick-hardening early-strength type soft soil curing agent based on ammonia alkali white mud and preparation method of quick-hardening early-strength type soft soil curing agent

Abstract

The invention relates to a quick-hardening early-strength type soft soil curing agent based on ammonia alkali white mud and a preparation method thereof. The quick-hardening early-strength type soft soil curing agent comprises the following components in percentage by weight: 10-40% of ammonia alkali white mud, 30-60% of mineral powder, 0-30% of steel slag powder, 5-20% of desulfurized gypsum, 0-15% of cement, 0-10% of lime and 0-3% of excitant. According to the invention, soft soil curing, rapid hardening and early strength effects can be realized, 1.0 MPa or more can be reached in one day, the construction period is shortened, and the cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of soft soil curing agents, and in particular to a rapid-hardening and early-strengthening soft soil curing agent based on ammonia-alkali white mud and a preparation method thereof. Background Art

[0002] Soft soil solidifiers are inorganic hydraulic cementitious materials used to solidify soft soil and other fine-grained soils. Currently, commonly used soft soil solidifiers include cement, lime, and various types of industrial solid waste composite solidifiers. The prices of cement and lime are relatively high, and due to their own characteristics, they are not well applied in many soil solidification fields such as saline soil, soil with high organic matter content, and soil with high water content. The production process of cement and lime also requires the emission of a large amount of carbon dioxide. At present, they are gradually replaced by low-cost and high-performance industrial solid waste composite solidifiers, but they generally have the problems of slow early reaction and low early strength. In order to obtain higher early strength, many studies have added strong alkali such as sodium hydroxide and water glass to stimulate industrial solid waste, or added early strength cement such as sulphoaluminate cement or aluminate cement to provide early strength. The cost of obtaining early strength remains high, and there is a certain risk in adding strong alkali in the actual construction process.

[0003] Ammonia-alkali white mud has the characteristics of high alkali, high chlorine, high sulfur and high fineness, which makes it difficult to use in the preparation of building materials. However, it has advantages in the preparation of soft soil solidifying agents, as it can play a role in chemical stimulation and physical filling.

[0004] In recent years, with the breakthrough of grinding technology, the building materials industry has achieved low-cost production of ultrafine powder. Higher early strength can be obtained through ultrafine mechanical activation, which is safer than chemical activation.

[0005] Authorization No. CN 102153326B (A soft soil solidifying agent and its application), the soft soil solidifying agent comprises 10-25% cement clinker, 65%-80% slag, 4-10% filling material, 1-10% expansion agent, 0.2-5% alkaline activator and 0.02-0.3% surfactant, wherein the filling material is fine sand and / or fly ash, the expansion agent is raw gypsum or desulfurized gypsum, the expansion agent is quicklime or sodium hydroxide; the surfactant is triethanolamine or calcium lignin sulfonate, and the amount of the soft soil solidifying agent is 8%-20% of the weight of the reinforced soil.

[0006] Authorization No. CN 102899048B (desulfurized gypsum alkali slag soil solidifier), the present invention discloses a desulfurized gypsum alkali slag soil solidifier, characterized in that: the material is prepared from the following components in weight percentage: desulfurized gypsum 12-30%, alkali slag 20-50%, slag 0-30%, admixture 0-5%, fly ash 0-20%; the sulfur trioxide content in the desulfurized gypsum is greater than 38wt%; the desulfurized gypsum is wet-discharged gypsum for flue gas desulfurization in power plants; the admixture is one or more of silicate, aluminate, and sulphoaluminate; the alkali slag is alkali slag that has been ground and has a specific surface area greater than 450m2 / kg. Preparation method: firstly, the alkali slag with a specific surface area greater than 450m2 / kg is mixed and ground with slag powder and fly ash for 15 minutes, and then the desulfurized gypsum and admixture are added and mechanically mixed for 10 minutes to obtain the desulfurized gypsum alkali slag soil solidifier. This patent does not reflect the rapid hardening and early strength of the soft soil curing agent. When the incorporation ratio is 10%, the 28d strength of the cured soil is relatively low, only 0.75 to 1.05 MPa, and is not suitable for applications with high strength requirements.

[0007] Application publication number CN 117776649A (Preparation method of a fast-hardening curing agent suitable for silt soft soil), the present invention relates to the technical field of silt soft soil, and discloses a preparation method of a fast-hardening curing agent suitable for silt soft soil, comprising the following preparation steps: 1) preparing the main material, the main material comprising fly ash, gypsum, aluminate cement and mineral powder; preparing the activator, the activator comprising quicklime, water glass and sodium hydroxide; according to the mass ratio, the ratio of the main material to the activator is (9.5-11): (0.8-1.2); 2) placing the main material and the activator in a mixer and stirring and mixing to form a mixture, placing the mixture and water in a mixer and stirring and mixing to form a curing agent, according to the mass ratio, the ratio of the mixture to the water is (0.9-1.3): (0.8-1.2). The activator components in the curing agent are quicklime, water glass and sodium hydroxide, which are relatively expensive and account for about 10%, and the cost is relatively high.

[0008] Currently, the disclosed patents and published documents rarely involve fast-hardening and early-strengthening soft soil solidifiers. At present, most of them use cement, mineral powder, fly ash, etc. as cementing materials, and use activators such as water glass, sodium hydroxide, sodium sulfate, etc. to stimulate the activity of admixtures such as mineral powder and fly ash to achieve strength development. In addition, in order to increase the coagulation and hardening speed, some patents add expensive sulphoaluminate cement or aluminate cement, resulting in a generally high cost of soft soil solidifiers. Therefore, a fast-hardening and early-strengthening soft soil solidifier based on ammonia-alkali white mud and a preparation method thereof are needed. Summary of the invention

[0009] The purpose of the present invention is to provide a rapid-hardening and early-strengthening soft soil curing agent based on ammonia-alkali white mud and a preparation method thereof.

[0010] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0011] In the first aspect, a fast-hardening and early-strengthening soft soil solidifier based on ammonia-alkali white mud is provided, which comprises, by weight, 10-40% ammonia-alkali white mud, 30-60% mineral powder, 0-30% steel slag powder, 5-20% desulfurized gypsum, 0-15% cement, 0-10% lime and 0-3% activator.

[0012] Furthermore, the ammonia-soda mud is solid waste generated during the preparation of soda ash by the ammonia-soda process. After being subjected to filter pressing, breaking up, airing and drying, the ammonia-soda mud having a moisture content of less than 5% is obtained, and the content of the ammonia-soda mud is greater than 99%.

[0013] Furthermore, the mineral powder is S95 grade granulated blast furnace slag powder with a specific surface area greater than 400m 2 / kg.

[0014] Furthermore, the steel slag powder is Grade II steel slag powder, with a specific surface area greater than 350m 2 / kg.

[0015] Furthermore, the desulfurized gypsum has a dihydrate gypsum content of >90%, is dried to a moisture content of <5%, and has a specific surface area of ​​200-400m 2 / kg.

[0016] Furthermore, the cement is one or more mixtures of 42.5 grade silicate cement, composite silicate cement or slag silicate cement.

[0017] Furthermore, the lime is a mixture of calcium oxide, calcium hydroxide and calcium carbonate, which is obtained by drying and passing through a 0.15 mm sieve.

[0018] Furthermore, the activator is any one of aluminum sulfate or alum or a mixture of the two.

[0019] In the second aspect, the preparation method of the rapid hardening and early strength soft soil curing agent based on ammonia-alkali white mud is as follows: ammonia-alkali white mud, mineral powder, steel slag powder, desulfurized gypsum, cement, lime, and activator are transported to an ultrafine ball mill for ultrafine grinding, and then the powder is sent to a powder separator for sorting to obtain a powder with a specific surface area of ​​more than 700m 2 / kg of product is a fast-hardening and early-strengthening soft soil solidifier.

[0020] The beneficial effects of the present invention are:

[0021] The present invention is a rapid-hardening and early-strengthening soft soil curing agent based on ammonia-alkali white mud and a preparation method thereof. Compared with the prior art, the present invention has the following technical effects:

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention can achieve the effect of fast hardening and early strengthening of soft soil, reaching above 1.0MPa in 1 day, thus shortening the construction period;

[0024] The invention uses ammonia-alkali white mud as a key raw material, and accounts for a relatively high proportion of the soft soil solidifying agent, thus opening up a way for its large-scale utilization. Since the proportion of industrial solid waste in the soft soil solidifying agent reaches more than 90%, the cost is relatively low. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is an electron microscope picture of the early-age hydration product of the solidified soil of the fast-hardening and early-strength soft soil solidifier based on ammonia-alkali white mud and its preparation method of the present invention. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The present invention comprises the following steps:

[0028] A fast-hardening and early-strengthening soft soil solidifier based on ammonia-alkali white mud is composed of ammonia-alkali white mud, mineral powder, steel slag powder, desulfurized gypsum, cement, lime and an activator, wherein the proportions of the components are: 10-40% of ammonia-alkali white mud, 30-60% of mineral powder, 0-30% of steel slag powder, 5-20% of desulfurized gypsum, 0-15% of cement, 0-10% of lime and 0-3% of an activator.

[0029] Ammonia-alkali white mud itself is alkaline, which can stimulate the mineral powder to cause the depolymerization of silicon-oxygen bonds and aluminum-oxygen bonds. It also has soluble chloride salts and sulfates, which can produce calcium aluminate and Fridel salt with mineral powder. At the same time, ammonia-alkali white mud is a nanoparticle, which can play a certain filling role after grinding and promote strength growth.

[0030] Mineral powder is the main body of the reaction, providing silicon-oxygen tetrahedrons and aluminum-oxygen tetrahedrons for the reaction system, and providing a basis for the formation of hydrated calcium silicate and ettringite.

[0031] Steel slag powder provides an alkaline environment for the reaction system. At the same time, the steel slag also generates a certain amount of calcium silicate hydrate gel. A small amount of aluminate in the steel slag will also react with desulfurized gypsum and chloride salt to generate ettringite and Friedel salt.

[0032] Desulfurized gypsum provides sulfate to the system and promotes the formation of calcium sulfide.

[0033] On the one hand, cement hydration produces hydrated calcium silicate and calcium hydroxide, which provide a source of strength and an alkaline environment.

[0034] Lime provides an alkaline environment for the system. Quicklime can absorb some of the moisture in the soft soil and reduce the water content. The heat released by absorbing water can also accelerate the hydration reaction. Calcium carbonate can provide a nucleation matrix for the hydration products and promote hydration.

[0035] Aluminum sulfate or alum provides soluble aluminum salts for early reactions, promoting the massive generation of calcium sulfide in the early stages and improving early strength.

[0036] After ultrafine grinding, the soft soil solidifier has a higher specific surface area. On the one hand, the required wetting water increases, so it can absorb the moisture in the soft soil and reduce the water content; on the other hand, the increase in specific surface area is more conducive to the effective contact of the various components, promoting the hydration reaction as soon as possible, thereby increasing the coagulation and hardening speed and early strength.

[0037]

[0038]

[0039] Implementation Case 1: Ammonia-soda white mud 10%, mineral powder 48%, steel slag powder 12%, desulfurized gypsum 15%, cement 9%, lime 5%, activator 1%, wherein the activator is aluminum sulfate.

[0040] Implementation Case 2: Ammonia-alkali white mud 18%, mineral powder 40%, steel slag powder 11%, desulfurized gypsum 13%, cement 7%, lime 9%, activator 2%, wherein the activator is a mixture of aluminum sulfate and alum.

[0041] Implementation Case 3: Ammonia-alkali white mud 24%, mineral powder 45%, steel slag powder 7%, desulfurized gypsum 12%, cement 10%, lime 2%.

[0042] Implementation Case 4: Ammonia-alkali white mud 32%, mineral powder 35%, steel slag powder 10%, desulfurized gypsum 10%, cement 3%, lime 8%, activator 2%, wherein the activator is a mixture of aluminum sulfate and alum.

[0043] Implementation Case 5: Ammonia-soda white mud 40%, mineral powder 36%, steel slag powder 5%, desulfurized gypsum 8%, cement 8%, lime 2%, activator 1%, wherein the activator is a mixture of aluminum sulfate and alum.

[0044] The ammonia-soda white mud, mineral powder, steel slag powder, desulfurized gypsum, cement, lime and activator are respectively measured and transported to the ultrafine ball mill for ultrafine grinding. After grinding, they are sent to the powder concentrator for sorting to obtain a powder with a specific surface area greater than 700m 2 / kg mixture, with a specific surface area of ​​less than 700m 2 / kg of mixed material is returned to the superfine ball mill for further grinding.

[0045]

[0046] like Figure 1 As shown, the ratio of soft soil stabilizer to the stabilized soil sample is 1:10, the soil sample has a moisture content of 40%, a plasticity index of 15%, and an organic matter content of 1.6%. Figure 1 Not only does it clearly reveal the details of the microstructure of the solidified soil, but it also intuitively proves the high performance of the solidifying agent and the scientific nature of the preparation method. Through these meticulous SEM images, we can deeply understand the formation and development of hydration products during the solidification process.

[0047] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A fast-hardening and early-strengthening soft soil curing agent based on ammonia-alkali white mud, characterized in that: The weight ratio is 10-40% ammonia-alkali white mud, 30-60% mineral powder, 0-30% steel slag powder, 5-20% desulfurized gypsum, 0-15% cement, 0-10% lime and 0-3% activator.

2. The rapid-hardening and early-strength soft soil curing agent based on ammonia-alkali white mud according to claim 1, characterized in that: The ammonia-soda mud is solid waste generated in the process of preparing soda ash by the ammonia-soda process. After filtering, breaking up, airing and drying, the ammonia-soda mud with a moisture content lower than 5% is obtained, and the content of the ammonia-soda mud is greater than 99%.

3. The rapid-hardening and early-strength soft soil curing agent based on ammonia-alkali white mud according to claim 1, characterized in that: The mineral powder is S95 grade granulated blast furnace slag powder with a specific surface area greater than 400m 2 / kg.

4. The rapid-hardening and early-strength soft soil curing agent based on ammonia-alkali white mud according to claim 1, characterized in that: The steel slag powder is Grade II steel slag powder with a specific surface area greater than 350m 2 / kg.

5. The rapid hardening and early strength soft soil curing agent based on ammonia-alkali white mud according to claim 1, characterized in that: The desulfurized gypsum has a dihydrate gypsum content of >90%, is dried to a moisture content of <5%, and has a specific surface area of ​​200-400m 2 / kg.

6. The rapid-hardening and early-strength soft soil curing agent based on ammonia-alkali white mud according to claim 1, characterized in that: The cement is one or more mixtures of 42.5 grade silicate cement, composite silicate cement or slag silicate cement.

7. The rapid-hardening and early-strengthening soft soil curing agent based on ammonia-alkali white mud according to claim 1, characterized in that: The lime is a mixture of calcium oxide, calcium hydroxide and calcium carbonate, which is obtained by drying and passing through a 0.15 mm sieve.

8. The rapid-hardening and early-strengthening soft soil curing agent based on ammonia-alkali white mud according to claim 1, characterized in that: The activator is any one of aluminum sulfate or alum or a mixture of the two.

9. A method for preparing a quick-hardening and early-strength soft soil curing agent based on ammonia-alkali white mud according to any one of claims 1 to 8, characterized in that: The ammonia-alkali white mud, mineral powder, steel slag powder, desulfurized gypsum, cement, lime and activator are transported to the ultrafine ball mill for ultrafine grinding. After grinding, they are sent to the powder concentrator for sorting to obtain a specific surface area of ​​more than 700m 2 / kg of product is a fast-hardening and early-strengthening soft soil solidifier.

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