CN116041031A - In-situ treatment technology of engineering slag soil with high water content - Google Patents

Abstract

The invention provides an in-situ treatment method for high moisture content dregs, which can be used to treat engineering dregs with a moisture content higher than 60%, specifically: through the combined use of uncalcined gypsum and calcined gypsum, a large amount of engineering dregs is absorbed At the same time, the bottom ash is used to reduce the influence of water in the high moisture content slag on the solidified material. The types of gypsum used in the present invention relate to titanium gypsum, phosphogypsum, and desulfurized gypsum. The types of gypsum involved are extensive, and the raw materials are all industrial products. The utilization rate of solid waste materials in solidified materials reaches 65%-100%, which reduces the solid waste in industrial production. The discharge of waste has the advantage of being environmentally friendly and is a green building material; at the same time, the dregs processed by the in-situ disposal technology of engineering dregs provided by the present invention have fast coagulation time and high strength after coagulation, which can effectively reduce engineering waste. cost.

Description

An In-Situ Disposal Technology of Engineering Slag with High Moisture Content

technical field

The invention relates to the field of engineering slag treatment, in particular to an in-situ disposal technology and application of high moisture content engineering slag.

Background technique

With the continuous development of my country's economic construction and the continuous acceleration of urbanization, the discharge of engineering dregs is also increasing year by year, which has become a major burden for my country's economic and social development. The rapid solidification of soil is of great significance in foundation treatment, rush repair and rush construction and other projects. For soil with low moisture content, there are many types of soil curing agents currently on the construction market, and the curing time is generally 16-24 hours, which are mainly divided into the following types:

(1) Traditional inorganic curing agents represented by lime and cement;

(2) Ionic soil stabilizer mainly for clayey soil;

(3) An organic soil stabilizer formulated from polymers, resins and macromolecular materials;

(4) Biological enzyme soil stabilizer made by fermenting organic matter.

Soil stabilizers with different action mechanisms have different application effects on soil mechanical properties, water stability, durability and dynamic properties, and the existing soil stabilizers have problems such as long construction period and potential environmental hazards. However, for high moisture content muck (moisture content > 60%), there is no clear standard and unified material to deal with it. Therefore, how to carry out in-situ rapid solidification and transfer of high-moisture-content muck is a key link in the implementation of in-situ disposal technology.

In recent years, due to the depletion of natural high-quality gypsum resources, titanium gypsum, phosphogypsum and desulfurized gypsum are important components of industrial by-product gypsum, and their resource reuse has become the focus of the gypsum industry.

The Chinese invention patent with the publication number CN102899048A discloses a desulfurization gypsum alkali slag soil curing agent, which is prepared from the following components in weight percentage: desulfurization gypsum 12-30%, alkali slag 20-50%, slag 0-50% 30%, admixture 0-5%, fly ash 0-20%. The invention uses alkali slag and slag as raw materials, and the prepared curing agent has the advantages of short initial setting time and high compressive strength. However, the curing agent strictly limits the amount of desulfurization gypsum and the particle size of alkali slag. At the same time, the curing agent can only be applied to soil with low moisture content, and cannot be applied to engineering dregs with high moisture content, which has certain limitations. sex.

The Chinese invention patent with the publication number CN113716927A discloses a phosphogypsum-based soil curing agent, a preparation method, a curing sample and a preparation method thereof. The phosphogypsum-based soil curing agent includes modified phosphogypsum and an active component, and the modified The mass ratio of active phosphogypsum to active components is 1: (0.5-1.5), and the modified phosphogypsum is obtained by calcining the original phosphogypsum and modifier A at a temperature of 800-900°C. The soil curing agent provided by the invention uses PO 42.5 cement as the soil curing sample strength of the soil curing material is higher, but the soil curing agent needs to be calcined at 800-900 ° C in the preparation process, and the preparation process is more complicated. Simultaneously, the water content of the soil needs to be maintained at a lower level (15wt-20wt%) when the solidifying agent is changed to solidify the soil, and in the actual construction production process, the water content of engineering dregs is often greater than the level of the invention, so the curing agent It also has great limitations in use.

To sum up, the existing inventions that use a single type of gypsum to solidify soil often depend on the soil particle size, water content and organic matter content, and the effect is not good for soil with high water content. A large number of pores exist, the water stability and durability are poor, and shrinkage and cracking are prone to occur. Therefore, developing an in-situ disposal method for soils with high water content has high social and economic benefits.

Contents of the invention

The problem to be solved by the invention is how to quickly solidify engineering dregs with high water content.

In order to solve the above problems, the present invention provides an in-situ disposal method for high-moisture engineering dregs, which can be used to treat engineering dregs with a moisture content greater than 60%.

Further, the in-situ disposal method of engineering dregs with high moisture content according to the present invention comprises the following steps:

S1. Preparation of curing material: in parts by mass, use 5-30 parts of uncalcined gypsum, 0-20 parts of calcined gypsum, 30-70 parts of furnace bottom ash, and 0-10 parts of water glass to prepare the curing material;

S2. Solidification of dregs: Add the solidified material prepared in step S1 into the engineering dregs with a moisture content greater than 60%, mix evenly, let stand, and complete the in-situ disposal after the engineering dregs reach a soft plastic state.

Preferably, in the step S1, the ratio of the sum of the mass of calcined gypsum and uncalcined gypsum to the mass of bottom ash is preferably (2-3):(6-7).

Further, the step S1 specifically includes: mixing uncalcined gypsum and calcined gypsum and stirring evenly, adding furnace bottom ash, stirring evenly, adding water glass and stirring evenly to obtain a solidified material.

For traditional high-moisture engineering dregs, the industry often uses the method of drying to dehydrate and solidify for transportation, but this method is time-consuming and labor-intensive. The in-situ disposal method for high-moisture engineering dregs described in the present invention is For engineering slag with high moisture content, there is no need to perform drying and dehydration operations on the engineering slag, and directly add uncalcined gypsum, calcined gypsum, furnace bottom ash, and water glass to the high moisture content engineering slag to make a solidified material. It can complete the solidification of high moisture content muck.

Preferably, the calcined gypsum is selected from one or more of titanium hemihydrate, phosphogypsum hemihydrate and desulfurized gypsum hemihydrate.

Further, the calcined gypsum is prepared by calcining one or more of titanium dihydrate, phosphogypsum dihydrate and desulfurized gypsum dihydrate at 180-250° C. for 2-5 hours.

Preferably, the uncalcined gypsum is selected from one or more of titanium dihydrate, phosphogypsum dihydrate and desulfurized gypsum dihydrate.

Although gypsum has water absorption, the water resistance of gypsum is poor. Adding bottom ash to gypsum can improve the water resistance of gypsum and solve the problem of poor water resistance of gypsum. At the same time, bottom ash also has a certain water absorption capacity, which can improve Water absorption of cured material.

Preferably, the modulus of the water glass is 1.0-1.5. .

Water glass is a kind of binding agent commonly used, and in the present invention, water glass is mainly used for bonding engineering slag.

Further, the mass of the solidified material is 10% to 30% of the mass of engineering dregs.

Preferably, in the step S2, the standing time is 2-12 hours.

The principle of the present invention is: the calcined gypsum has a very strong water absorption ability after calcined, and the water in the engineering dregs with high moisture content is used as the reaction water, and the compound of calcined gypsum and non-calcined gypsum is used to absorb water, and the hardness of the gypsum will increase after absorbing water , so that the engineering dregs are solidified and the hardness is improved. Bottom ash can assist gypsum to absorb water in engineering slag and solve the problem of poor water resistance of gypsum.

Beneficial effects of the present invention: the present invention provides an in-situ treatment method for high moisture content dregs, which can be used to treat engineering dregs with a moisture content higher than 60%, specifically: through the combined use of uncalcined gypsum and calcined gypsum , Absorb a large amount of water in engineering slag, and at the same time use bottom ash to reduce the impact of water in high moisture content slag on solidified materials. The types of gypsum used in the present invention relate to titanium gypsum, phosphogypsum, and desulfurized gypsum, and the types of gypsum involved are extensive; the raw materials used in the present invention are all industrial products, and the utilization rate of solid waste materials in solidified materials reaches more than 90%, which reduces industrial production The discharge of solid waste in the environment has the advantage of being environmentally friendly, and it is a green building material; at the same time, the dregs treated by the in-situ disposal technology of engineering dregs provided by the present invention have fast coagulation time and high strength after coagulation, which can effectively Reduce engineering costs.

Description of drawings

Fig. 1 is a flow chart of the in-situ disposal method for high moisture content dregs proposed by the present invention.

Detailed ways

In order to make the above objects, features and advantages of the present invention more comprehensible, specific embodiments of the present invention will be described in detail below. It should be noted that the following examples are only used to illustrate the implementation method and typical parameters of the present invention, and are not used to limit the scope of the parameters described in the present invention, and the reasonable changes derived from this are still protected by the claims of the present invention within range.

It should be noted that neither the endpoints of the ranges nor any values disclosed herein are limited to the precise ranges or values, and these ranges or values are understood to include values approaching these ranges or values. For numerical ranges, between the endpoints of each range, between the endpoints of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, these values Ranges should be considered as specifically disclosed herein.

In order to solve the problem that the existing technology cannot effectively solidify engineering dregs with high water content, the specific embodiment of the present invention provides an in-situ disposal technology and application of high water content engineering dregs. The in-situ treatment technology of high-rate slag includes: using calcined gypsum and uncalcined gypsum to compound, which can absorb a large amount of water in engineering slag and harden it to improve the consolidation strength. Applying furnace bottom ash solves the problem of water resistance of gypsum. Adhesives can bond engineering dregs. use this method

Example 1

Among them, 30 parts of titanium gypsum hemihydrate, 10 parts of phosphogypsum dihydrate, 10 parts of desulfurized gypsum dihydrate, 45 parts of furnace bottom ash, and 5 parts of water glass (modulus 1.0) were weighed to form a solidified material after mixing evenly. Weigh 10 parts of solidified material and 90 parts of engineering dregs with 70% water content for mixing.

Example 2

Weigh 40 parts of titanium gypsum hemihydrate, 5 parts of phosphogypsum dihydrate, 5 parts of desulfurized gypsum dihydrate, 40 parts of furnace bottom ash, and 10 parts of water glass (modulus 1.0) and mix them uniformly to form a solidified material. Weigh 30 parts of solidified material and 70 parts of engineering dregs with 90% water content for mixing.

Example 3

Weigh 30 parts of titanium gypsum hemihydrate, 10 parts of titanium gypsum dihydrate, 5 parts of phosphogypsum dihydrate, 5 parts of desulfurized gypsum dihydrate, 40 parts of furnace bottom ash, 10 parts of water glass (modulus 1.0) and mix them evenly to become a solidified material . Weigh 10 parts of solidified material and 90 parts of engineering dregs with 70% moisture content.

The time required for the construction dregs of Examples 1 to 3 to reach a transportable state was measured.

The results are shown in Table 1.

Each embodiment of table 1 reaches the required time of transportable state

group Time required to reach transportable state/h Example 1 8 Example 2 10 Example 3 8

By observing, measuring and comparing the solidified soil samples of the three groups of examples, it can be preliminarily concluded that the primary and secondary relationship of solid waste materials affecting the solidified consistency state is: furnace bottom ash > uncalcined titanium gypsum > calcined titanium gypsum > dihydrate gypsum > semi water gypsum.

Example 4

Measure the strength of engineering dregs after engineering dregs in situ disposal technology in embodiment 1-embodiment 3, the steps are as follows:

Step 1: Weigh 1000g of dry muck, add water to make the moisture content of the soil reach 80%, stir and set aside;

Step 2: Add the solidified material prepared in Examples 1 to 3 into the soil with high moisture content according to the mass fraction of 10%, and stir evenly;

Step 3: After completing the above operations, place the soil in a 40mm cube test block mold, cover it with plastic wrap, put it in a cool place, cover the surface with a wet towel, and test its unconfined compressive strength for 3d and 7d. The results are shown in Table 2.

group 3d compressive strength/MPa 7d compressive strength/MPa Example 1 0.6 0.83 Example 2 0.59 1.05 Example 3 0.49 1.03

Example 5

Determination of the strength of engineering dregs after typical group of engineering dregs in-situ disposal technology in embodiment 1-embodiment 3, the steps are as follows:

Step 1: Weigh 1000g of dry muck, add water to make the soil moisture content reach 60%, stir and set aside;

Step 2: Add the prepared curing material into the soil with high moisture content according to the mass fraction of 10%, and stir evenly;

Step 3: After completing the above operations, place the soil in a 40mm cube test block mold, cover it with plastic wrap, put it in a cool place, cover the surface with a wet towel, and test its unconfined compressive strength for 3d and 7d. The results are shown in table 3.

group 3d compressive strength/MPa 7d compressive strength/MPa Example 1 0.6 0.83 Example 2 0.59 1.05 Example 3 0.49 1.03

The results show that the 7d compressive strength of the engineering dregs processed by the in-situ disposal technology of the engineering dregs provided by the present invention can reach about 1 MPa, and the strength is relatively high.

Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will all fall within the protection scope of the present invention.

Claims (9)

1. The in-situ treatment method of the engineering slag soil with high water content is characterized by comprising the following steps of:

s1, preparing a curing material: mixing 5-30 parts of uncalcined gypsum, 0-20 parts of calcined gypsum, 30-70 parts of bottom ash and 0-10 parts of water glass according to parts by mass to prepare a curing material;

s2, curing dregs: and (3) doping the solidified material prepared in the step (S1) into engineering slag soil with the water content of more than 60%, uniformly mixing, standing, and finishing in-situ treatment after the engineering slag soil reaches a soft plastic state.

2. The method for in-situ disposal of high water content engineering slag as defined in claim 1, wherein in said step S1, the ratio of the sum of the mass of calcined gypsum and uncalcined gypsum to the mass of bottom ash is (2-3): (6-7).

3. The method for in-situ treatment of high water content engineering slag according to claim 1 or 2, wherein the step S1 specifically comprises: mixing the uncalcined gypsum and the calcined gypsum, stirring uniformly, adding the bottom ash, stirring uniformly, adding the water glass, and stirring uniformly to obtain the cured material.

4. The in situ treatment method of high water content engineering slag according to claim 3, wherein the calcined gypsum is one or more selected from the group consisting of titanium hemihydrate gypsum, phosphogypsum hemihydrate and desulfurization hemihydrate gypsum.

5. The method for in-situ treatment of high water content engineering slag according to claim 4, wherein the calcined gypsum is prepared by calcining one or more of titanium dihydrate gypsum, phosphogypsum dihydrate and desulfurization dihydrate gypsum at 180-250 ℃ for 2-5 hours.

6. The method for in situ disposal of high moisture content engineering slag as defined in claim 3, wherein said uncalcined gypsum is selected from one or more of titanium dihydrate gypsum, phosphogypsum dihydrate and desulfurization dihydrate gypsum.

7. The in-situ treatment method of high-water-content engineering slag soil according to claim 1, wherein the modulus of the water glass is 1.0-1.5.

8. The in-situ treatment method of high water content engineering slag soil according to claim 1, wherein in the step S2, the mass of the solidified material is 10% -30% of the mass of the engineering slag soil.

9. The method for in-situ treatment of high water content engineering slag as defined in claim 1, wherein in step S2, the standing time is 2-12 hours.

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