Alkali residue-based fluidized stabilized soil and preparation method thereof

Abstract

The invention provides alkaline residue-based fluidized stabilized soil and a preparation method thereof, and belongs to the technical field of comprehensive utilization of solid wastes. The alkaline residue-based fluid solidified soil comprises the following components: alkaline residue, a curing agent, an admixture, water and an additive, wherein the mass ratio of the water to a dry basis is (0.85-1.45): 1; the mass ratio of the additive to the curing agent is (0.001-0.01): 1. The preparation device comprises an alkaline residue slurrying system, a fluid-state solidified soil slurry preparation system, a pumping pouring system and an intelligent control platform, and the operation control problem caused by high water content and large water content fluctuation of alkaline residues can be effectively solved by optimizing the slurrying mode and the technological process.

Description

Technical Field

[0001] The invention relates to an alkali slag-based fluidized solidified soil and a preparation method thereof, belonging to the technical field of comprehensive utilization of solid wastes. Background Art

[0002] Fluidized solidified soil is a new type of geotechnical engineering material. This material is made by adding an appropriate amount of curing agent and water to suitable soil materials, stirring them into a mixture with a certain fluidity, and then solidifying them into an engineering material with a certain strength, water stability, low permeability and long-term stability after pouring or filling and curing. Thanks to the extremely high raw material tolerance of fluidized solidified soil, the soil materials used in fluidized solidified soil can not only be local rock and soil, loam and excavated trench soil, but also inorganic solid waste materials such as fine particles of construction waste, engineering mud, silt, tailings, blast furnace slag, and carbide slag.

[0003] Alkali residue is the solid waste generated in the process of producing soda ash by the ammonia-soda process. Since the late 1980s, the main methods of disposing alkali residue from alkali plants in my country have been measures such as building dams to store residue and discharging clear liquid into the sea (river). This solid residue method has caused long-term storage of alkali residue, which not only occupies a large amount of land resources, but also brings a series of environmental problems. The resource utilization of alkali residue has become an urgent need for current environmental protection, but alkali residue has technical difficulties such as high water content, difficulty in digesting chlorides, and viscous mud that is difficult to separate. It has a high pH value and is corrosive to a certain extent, making it difficult to reuse in industrial production.

[0004] Alkali slag can be used to prepare engineering soil or building materials such as bricks and cement due to its high calcium content, fine particle size, high pH value and high activity. It is highly feasible to use alkali slag to prepare fluidized solidified soil, and it has been applied and promoted in the Lianyungang alkali slag treatment project. The alkaline substances in the alkali slag can be used as activators to further improve the performance of cementitious materials. At the same time, salts such as calcium chloride contained in the alkali slag have the effect of promoting cement hydration reaction. The addition of cement and other curing agents is also conducive to the solidification of chloride ions in the alkali slag.

[0005] At present, the raw soil used in the preparation of fluidized solidified soil is mainly rock, loam, excavated trench soil and other soil materials with relatively low water content. There has been no relevant report on the use of alkali slag as raw soil to prepare fluidized solidified soil. Due to the fine particle size, high water content (50%-70%), and strong water retention of alkali slag, when alkali slag is used to prepare alkali slag-based fluidized solidified soil, the mixing water consumption far exceeds the water consumption required for the preparation of ordinary fluidized solidified soil. It is necessary to solve the problems of precise metering and control of water and other materials, pumping of viscous slurry, and later curing to prevent cracking. At the same time, alkali slag is generally stored for a long time, and there are debris such as lumps and stones. The use of alkali slag to prepare fluidized solidified soil also requires the screening and crushing of high-water content materials.

[0006] Therefore, there is an urgent need in the art for a method for preparing alkali slag-based fluidized solidified soil having high fluidity, good strength, high alkali slag utilization rate, and not prone to cracking, which can utilize the existing alkali slag. Summary of the invention

[0007] The purpose of the present invention is to solve the problem in the prior art that alkali residue has not yet been used as raw material soil to prepare fluidized solidified soil.

[0008] In order to achieve the purpose of solving the above problems, the technical solution adopted by the present invention is to provide an alkali slag-based fluidized solidified soil and a preparation method thereof.

[0009] In a first aspect of the present invention, there is provided an alkali slag-based fluidized solidified soil, comprising a dry base, water and an admixture, wherein the mass ratio of water to the dry base is (0.85-1.45):1; the fluidity of the alkali slag-based fluidized solidified soil is 160-220 mm;

[0010] Wherein, the dry basis comprises the following components:

[0011] 40-56 parts of alkali residue;

[0012] 20-40 parts of curing agent;

[0013] 20-24 parts of admixture;

[0014] Among them, each component is a mass ratio, the sum of the weight is 100 parts, and the mass ratio of the admixture to the curing agent is (0.001-0.01):1.

[0015] Preferably, the alkali residue is wet alkali residue stored in an alkali residue pool or dry residue formed by filtering, dehydrating and mixing the wet alkali residue with auxiliary materials.

[0016] Preferably, the curing agent material is cement or a cement-based composite cementitious material.

[0017] Preferably, the admixture is fly ash, and its fineness reaches Grade III ash or above.

[0018] The second aspect of the present invention provides a method for preparing the above-mentioned alkali slag-based fluidized solidified soil, comprising the following steps:

[0019] Step 1, after the alkali residue is preliminarily screened and the initial moisture content is measured, it is transported to the alkali residue wet grinding machine, water is added through a water supply device, and ground into a uniform wet alkali residue slurry, wherein the wet alkali residue slurry has a solid content of 30% to 40% and a density of 1100kg / ㎡ to 1200kg / ㎡;

[0020] The water intake can be calculated by the following formula:

[0021] m water = m alkali residue (aa·xx) + a (m cement + m fly ash)

[0022] Where: m 水 Indicates the quality of incoming water during a fixed period of time;

[0023] m 碱渣 Indicates the quality of alkali slag in a fixed time period;

[0024] m 水泥 It indicates the quality of cement fed in a fixed time period;

[0025] m 粉煤灰 It represents the mass of fly ash fed into the system within a fixed time period;

[0026] a represents the set water-to-solid ratio, and its value range is 0.85-1.45;

[0027] x represents the measured moisture content of alkali residue, and its value is less than 1;

[0028] Step 2, placing the wet alkali slag slurry prepared in step 1 into an alkali slag wet slurry tank, stirring the prepared wet alkali slag slurry to ensure that the slurry is uniformly mixed before pumping;

[0029] Step 3: according to the above proportions, the alkali slag slurry, curing agent, admixture and additive are prepared into an alkali slag-based fluidized solidified soil mixture through a fluidized solidified soil slurry preparation system; the prepared alkali slag-based fluidized solidified soil mixture has an initial fluidity of 160 to 220 mm, and the fluidity can be adjusted by adding a water reducing agent during long-distance pumping, and the control value is ≤340 mm;

[0030] Step 4, slurry stirring: the alkali slag-based fluidized solidified soil mixture in step 3 flows into the fluidized solidified soil temporary storage tank, is stirred evenly, and then pumped by a slurry pump;

[0031] Step 5, slurry pumping and pouring: the slurry pump pumps the slurry in the temporary storage tank of the alkali slag-based fluidized solidified soil to the pouring area;

[0032] Step 6, curing and forming of fluidized solidified soil: the alkali slag-based fluidized solidified soil is poured in sections and layers. Wait until the next layer of filler reaches the designed strength before pouring the next layer. Cover the poured solidified soil and maintain moisture retention. Make test pieces during the pouring process, perform simultaneous curing, and test the compressive strength.

[0033] Preferably, in the step 1, the alkali residue wet pulping machine can be a roller mill or a steel ball mill; the moisture content of the wet alkali residue slurry is measured by an online moisture content monitoring device, the online moisture content monitoring device is a microwave moisture meter or a near-infrared moisture meter, and the water supply device includes a water inlet pipe arranged at the feed port of the alkali residue wet pulping machine, and the water inlet pipe is equipped with an electric regulating valve for adjusting the water inlet flow rate according to the changes in the moisture content of the alkali residue and the amount of slag fed.

[0034] Preferably, in the step 1, the prepared wet alkali residue slurry passes through a slurry screen and enters an alkali residue wet slurry tank.

[0035] Preferably, in the step 2, an agitator is provided in the alkali residue wet slurry pool, a coarse slurry pool is provided above the agitator, the outlet of the coarse slurry pool is connected to the inlet of the fine slurry pool, the coarse slurry pool and the fine slurry pool are separated by a partition net, and a first slurry pump is provided inside the fine slurry pool; wherein, the agitator is used to make the material uniform and prevent water separation, the partition net is used to further classify the coarse and fine slurries and prevent large particles from entering the fine slurry pool, and the first slurry pump is used to pump the slurry in the fine slurry pool through a conveying hose into the mixing barrel of the fluidized solidified soil slurry preparation system.

[0036] Preferably, in the step 3, the fluidized solidified soil slurry preparation system includes a curing agent feed bin and an admixture feed bin, the outlets of the curing agent feed bin and the admixture feed bin are connected to the inlet of a feeder, the outlet of the feeder is connected to the inlet of a mixing barrel, the outlet of the mixing barrel is connected to the inlet of a discharge valve, and the outlet of the discharge valve is connected to a temporary storage tank for fluidized solidified soil.

[0037] Preferably, the feeder is provided with an automatic metering device, which can realize online real-time continuous dynamic measurement of the conveyed curing agent and admixture; the bottom of the mixing barrel is provided with an automatic metering device, which can realize online real-time continuous dynamic measurement of the input material weight and water volume; the top of the mixing barrel is provided with an alarm prompt light, which will give a prompt when the feed amount of each material reaches the set value of the single barrel; the agitator in the mixing barrel is provided with a control system, which is connected to the automatic control platform to realize automatic control of the start and stop of the agitator and the running mixing time; a discharge pipe is installed at the bottom of the mixing barrel, and an electric discharge valve is installed on the discharge pipe, which automatically opens for discharge after the required mixing time is reached.

[0038] Preferably, in the step 4, a second agitator is installed in the fluidized solidified soil temporary storage pool, a second coarse slurry pool is provided above the second agitator, a horizontal filter screen is provided above the second coarse slurry pool, the outlet of the second coarse slurry pool is connected to the inlet of the second fine slurry pool, the second coarse slurry pool and the second fine slurry pool are separated by a second dividing net, and a second slurry pump is provided inside the second fine slurry pool; wherein, the second agitator is used to make the material uniform and prevent water separation, the horizontal filter screen is used to perform preliminary filtration on the fluidized solidified soil slurry flowing out of the mixing barrel to screen out large particles therein, the second dividing net is used to further classify the coarse and fine slurries to prevent larger particles from entering the second fine slurry pool, and the second slurry pump is used to pump the fluidized solidified soil slurry in the fine slurry pool to the fluidized solidified soil pouring area through a conveying hose.

[0039] Preferably, in steps 1 to 6, automatic control of the system is achieved through a PLC automatic control program of an intelligent control platform.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) Provide an alkali slag-based fluidized solidified soil, comprising the following components, in terms of dry basis weight percentage: 40-56 parts of alkali slag, 20-40 parts of a curing agent, 20-24 parts of an admixture, and 40-80 parts of water; the sum of the dry basis weights of the alkali slag, the curing agent, and the admixture is 100 parts, and the ratio of water to solid material is 0.85-1.45; the admixture is 0.04-0.1 parts, and the prepared alkali slag-based fluidized solidified soil has a fluidity of 160-220 mm, and the fluidity is adjusted by adding a water reducing agent during long-distance pumping, and the control value is ≤340 mm;

[0042] (2) Provide a process flow of alkali slag-based fluidized solidified soil production equipment, the fluidized solidified soil preparation of which includes the following production equipment: alkali slag slurry making system, fluidized solidified soil slurry preparation system, pumping and pouring system and intelligent control platform. By optimizing the slurry making method and process flow, the operation control problems caused by the high water content and large fluctuation of the water content of the alkali slag can be effectively solved;

[0043] (3) The alkali slag-based fluidized solidified soil has a wide adjustment range, high fluidity, good strength, high alkali slag utilization rate, and is not easy to crack, which effectively solves the problem of alkali slag resource utilization;

[0044] (4) The produced fluidized solidified soil has a low cost and can meet the needs of the building materials and cement industries, which is conducive to promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 The present invention provides a process for preparing alkali slag-based fluidized solidified soil;

[0046] Figure 2 Prepare a flow chart for fluidized soil consolidation. DETAILED DESCRIPTION

[0047] In order to make the present invention more clearly understood, a preferred embodiment is described in detail with reference to the accompanying drawings as follows:

[0048] like Figure 1 As shown, the present invention provides an alkali slag-based fluidized solidified soil and a preparation method thereof.

[0049] Example

[0050] The present invention can be divided into an alkali slag slurry making system, a fluidized solidified soil slurry preparation system, a pumping and pouring system and an intelligent control platform.

[0051] The main function of the alkali residue pulping system is to prepare the stored dry alkali residue into alkali residue slurry that is easy to transport in liquid form through equipment such as transportation, dry residue screening, wet grinding and slurry screening. The slurry preparation process is as follows:

[0052] Step 1, the dry alkali slag passes through the feeding and screening integrated machine to preliminarily screen out large debris, the moisture content of the screened material is monitored online, and the material enters the feed port of the alkali slag wet grinder; according to the measured moisture content of the alkali slag and the set water-solid ratio, the required water intake and slag intake within a fixed time period can be calculated, and the speed of the water supply pipe electric regulating valve and the feeding and screening integrated machine is controlled; water and dry alkali slag are crushed by a crushing device in the alkali slag wet grinder to form liquid slurry; the liquid slurry flows out from the slurry outlet pipe of the alkali slag wet grinder and enters the slurry screener;

[0053] Step 2: The liquid slurry is filtered out of large particles on a fixed vibrating screen of a slurry screener, and the filtered slurry flows into an alkali slag wet slurry tank from a slurry screener outlet, and large particles are discharged from a slurry screener outlet;

[0054] Step 3: The alkali slag liquid slurry, curing agent, admixture and additive flowing into the alkali slag wet slurry pool are mixed by a stirrer, filtered by a separator, and finally prepared into a wet alkali slag slurry in a fine slurry pool, which is pumped to a mixing barrel by the first slurry pump to obtain a fluidized solidified soil mixture.

[0055] The fluidized solidified soil mixture described in step 4 and step 3 flows into the fluidized solidified soil temporary storage tank, is stirred evenly, and then pumped by a slurry pump.

[0056] Step 5: The pumping and pouring system is used to pump the prepared alkali slag-based fluidized solidified soil to the pouring area.

[0057] Step 6: Pour the fluidized solidified soil in sections and layers. When the next layer of filler reaches the designed strength, pour the next layer. Cover the poured solidified soil and maintain moisture retention. During the pouring process, make test pieces, perform simultaneous maintenance, and test the compressive strength.

[0058] The intelligent control platform realizes automatic control of the system through the PLC automatic control program, and can collect data such as the weight of various materials such as curing agent, admixture, dry alkali slag, alkali slag wet slurry, water, working time of mixing equipment, valve opening, inverter frequency, flow rate, alkali slag moisture content, slurry solid content, etc. in real time.

[0059] The mass of components in each embodiment is shown in the following table:

[0060]

[0061] The above is only a preferred embodiment of the present invention, and is not any formal or substantial limitation of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the present invention, and these improvements and supplements should also be regarded as the protection scope of the present invention. Any technician familiar with this profession, without departing from the spirit and scope of the present invention, can make some changes, modifications and equivalent changes made by using the technical content disclosed above, which are equivalent embodiments of the present invention; at the same time, any changes, modifications and evolutions of any equivalent changes made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An alkali slag-based fluidized solidified soil, characterized in that: Including dry basis, water and admixture, the mass ratio of water to dry basis is (0.85-1.45):1; Wherein, the dry basis comprises the following components: 40-56 parts of alkali residue; 20-40 parts of curing agent; 20-24 parts of admixture; Among them, each component is a mass ratio, the sum of the weight is 100 parts, and the mass ratio of the admixture to the curing agent is (0.001-0.01):

1.

2. The alkali slag-based fluidized solidified soil according to claim 1, characterized in that: The alkali slag is wet alkali slag stored in the alkali slag pool or dry slag formed by filtering, dehydrating and mixing auxiliary materials; the curing agent material is cement or cement-based composite cementitious material; the admixture is fly ash, and its fineness reaches Grade III ash or above.

3. A method for preparing alkali slag-based fluidized solidified soil as claimed in claim 1 or 2, characterized in that: The following steps are involved: Step 1, after the alkali residue is preliminarily screened and the initial moisture content is measured, it is transported to the alkali residue wet grinding machine, water is added through a water supply device, and ground into a uniform wet alkali residue slurry, wherein the wet alkali residue slurry has a solid content of 30% to 40% and a density of 1100kg / ㎡ to 1200kg / ㎡; The water intake can be calculated by the following formula: m 水 =m 碱渣 (a-a·x-x)+a(m 水泥 +m 粉煤灰 ) Where: m 水 Indicates the quality of incoming water during a fixed period of time; m 碱渣 Indicates the quality of alkali slag in a fixed time period; m 水泥 It indicates the quality of cement fed in a fixed time period; m 粉煤灰 It represents the mass of fly ash fed into the system within a fixed time period; a represents the set water-to-solid ratio, and its value range is 0.85-1.45; x represents the measured moisture content of alkali residue, and its value is less than 1; Step 2, placing the wet alkali slag slurry prepared in step 1 into an alkali slag wet slurry tank, stirring the prepared wet alkali slag slurry to ensure that the slurry is uniformly mixed before pumping; Step 3: according to the above proportions, the alkali slag slurry, curing agent, admixture and additive are prepared into an alkali slag-based fluidized solidified soil mixture through a fluidized solidified soil slurry preparation system; the prepared alkali slag-based fluidized solidified soil mixture has an initial fluidity of 160 to 220 mm, and the fluidity can be adjusted by adding a water reducing agent during long-distance pumping, and the control value is ≤340 mm; Step 4, slurry stirring: the alkali slag-based fluidized solidified soil mixture in step 3 flows into the fluidized solidified soil temporary storage tank, is stirred evenly, and then pumped by a slurry pump; Step 5, slurry pumping and pouring: the slurry pump pumps the slurry in the fluidized solidified soil temporary storage tank to the pouring area; Step 6, curing and forming of fluidized solidified soil: the fluidized solidified soil is poured in sections and layers, and the next layer of filler is poured after it reaches the designed strength. The poured solidified soil is covered and maintained to retain moisture. Test pieces are made during the pouring process, and curing is performed simultaneously to test the compressive strength.

4. The method for preparing the alkali slag-based fluidized solidified soil according to claim 3, characterized in that: In the step 1, the alkali residue wet pulping machine is a roller mill or a steel ball mill; the moisture content of the wet alkali residue slurry is measured by an online moisture content monitoring device, the online moisture content monitoring device is a microwave moisture meter or a near-infrared moisture meter, and the water supply device includes a water inlet pipe arranged at the feed port of the alkali residue wet pulping machine, and the water inlet pipe is equipped with an electric regulating valve for adjusting the water inlet flow rate according to the changes in the moisture content of the alkali residue and the amount of slag fed.

5. The method for preparing the alkali slag-based fluidized solidified soil according to claim 3, characterized in that: In the step 1, the prepared wet alkali residue slurry passes through a slurry screen and enters an alkali residue wet slurry tank.

6. The method for preparing the alkali slag-based fluidized solidified soil according to claim 3, characterized in that: In the step 2, an agitator is provided in the alkali residue wet slurry pool, a first coarse slurry pool is provided above the agitator, the outlet of the first coarse slurry pool is connected to the inlet of the first fine slurry pool, the first coarse slurry pool and the first fine slurry pool are separated by a partition net, and a first slurry pump is provided inside the first fine slurry pool; wherein, the agitator is used to make the material uniform and prevent water separation, the partition net is used to further classify the coarse and fine slurries and prevent large particles from entering the fine slurry pool, and the first slurry pump is used to pump the slurry in the fine slurry pool through a conveying hose to the mixing barrel of the fluidized solidified soil slurry preparation system.

7. The method for preparing the alkali slag-based fluidized solidified soil according to claim 3, characterized in that: In the step 3, the fluidized solidified soil slurry preparation system includes a curing agent feed bin and an admixture feed bin, the outlets of the curing agent feed bin and the admixture feed bin are connected to the inlet of the feeder, the outlet of the feeder is connected to the inlet of the mixing barrel, the outlet of the mixing barrel is connected to the inlet of the discharge valve, and the outlet of the discharge valve is connected to the fluidized solidified soil temporary storage tank.

8. The method for preparing alkali slag-based fluidized solidified soil according to claim 7, characterized in that: The feeder is provided with an automatic metering device, which can realize online real-time continuous dynamic measurement of the conveyed curing agent and admixture; the bottom of the mixing barrel is provided with an automatic metering device, which can realize online real-time continuous dynamic measurement of the input material weight and water volume; the top of the mixing barrel is provided with an alarm prompt light, which will give a prompt when the feed amount of each material reaches the single barrel set value; the agitator in the mixing barrel is provided with a control system, which is connected to the automatic control platform to realize automatic control of the start and stop of the agitator and the running mixing time; a discharge pipe is installed at the bottom of the mixing barrel, and an electric discharge valve is installed on the discharge pipe, which automatically opens for discharge after the required mixing time is reached.

9. The method for preparing alkali slag-based fluidized solidified soil according to claim 3, characterized in that: In the step 4, a second agitator is installed in the fluidized solidified soil temporary storage pool, a second coarse slurry pool is provided above the second agitator, a horizontal filter screen is provided above the second coarse slurry pool, the outlet of the second coarse slurry pool is connected to the inlet of the second fine slurry pool, the second coarse slurry pool and the second fine slurry pool are separated by a second dividing net, and a second slurry pump is provided inside the second fine slurry pool; wherein, the second agitator is used to make the material uniform and prevent water separation, the horizontal filter screen is used to perform preliminary filtration on the fluidized solidified soil slurry flowing out of the mixing barrel to screen out large particles therein, the second dividing net is used to further classify the coarse and fine slurries to prevent larger particles from entering the second fine slurry pool, and the second slurry pump is used to pump the fluidized solidified soil slurry in the fine slurry pool to the fluidized solidified soil pouring area through a conveying hose.

10. The method for preparing alkali slag-based fluidized solidified soil according to claim 3, characterized in that: The steps 1 to 6 described above realize automatic control of the system through the PLC automatic control program of the intelligent control platform.

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