Highway phosphogypsum modified material under new excitation system and preparation method and device thereof

Abstract

The invention relates to a phosphogypsum modified material for a highway under a new excitation system and a preparation method and device thereof, and belongs to the technical field of highway engineering in traffic transportation engineering. The modified material comprises the following raw materials in percentage by weight: 80-90% of phosphogypsum and 10-20% of a modifier, totaling 100%, the mass of the water is 15%-18% of the total mass of the phosphogypsum and the exciting agent; the modifier comprises the following raw materials: calcium oxide, silicon dioxide, ferric oxide, aluminum oxide, mineral powder, tricalcium silicate, calcium carbonate, sodium silicate, a coupling agent, iron powder and rubber powder. The ardealite modified material has the advantages of excellent strength increase and stability improvement in the aspect of long-term performance development, is high in environmental protection property, free of pollution to the environment, soil and water, good in economical efficiency and easy to popularize and apply, and does not increase the comprehensive construction cost of a project.

Description

Technical Field

[0001] The invention belongs to the technical field of highway engineering in transportation engineering, and specifically relates to a phosphogypsum modified material for highway under a new excitation system and a preparation method and device thereof. Background Art

[0002] At present, we should earnestly promote the efficient and high-quality utilization of phosphorus resources and the reduction, resource utilization, harmlessness and comprehensive utilization of phosphogypsum. my country is one of the countries with the largest production and storage of phosphogypsum materials. According to statistics from the China Phosphate and Compound Fertilizer Industry Association, by 2023, my country's annual production of phosphogypsum materials will be about 81 million tons, and the cumulative storage volume will exceed 800 million tons, mainly concentrated in Yunnan, Guizhou, Hubei, Sichuan and Anhui provinces. It is proposed in a document that by 2026, the comprehensive utilization rate of phosphogypsum will reach 65%, and the comprehensive consumption (including comprehensive utilization and harmless treatment) will achieve a dynamic balance with the production volume. Improving the comprehensive utilization of phosphogypsum and improving the quality of comprehensive utilization of phosphogypsum through multiple channels and scenarios has become the main task and difficulty to be overcome at this stage.

[0003] The main component of phosphogypsum is CaSO4·2H2O, and its main chemical components include SO3, CaO, SiO2, P2O5, Al2O3, Fe2O3, MgO, Na2O, K2O, F and crystal water. Among them, impurities such as fluoride, free phosphoric acid, P2O5, phosphate, etc. are easy to cause environmental pollution. Long-term contact with phosphogypsum may have adverse effects on human body, environment, groundwater and soil.

[0004] In highway engineering, phosphogypsum solid waste materials are mostly used in highway pavement bases; the large-scale use of phosphogypsum solid waste materials can reduce pollution and impact on the environment. However, there is no good treatment method for phosphogypsum materials at this stage. Cement-based materials are mainly used to solidify phosphogypsum materials. This method also shows obvious defects, mainly low early strength, poor water stability, poor volume stability, expansion cracking and other phenomena. Therefore, it is urgent to develop targeted high-dosage, high-quality comprehensive application technology for phosphogypsum solid waste.

[0005] At present, in highway projects, phosphogypsum solid waste materials are mainly used for road base to replace cement-stabilized gravel base, that is, the utilization of phosphogypsum solid waste mainly adopts the method of cement-based material solidification, using the existing cement-stabilized gravel base mixing plant for mixing, and using heavy rollers to roll and shape according to the designed compaction degree. Through maintenance under specified conditions, phosphogypsum reaches a certain strength and stability, and is used for highway base materials to replace cement-stabilized gravel base. This method has obvious shortcomings. First, cement is used to solidify phosphogypsum materials, which have low early strength, poor water stability, poor volume stability, and are prone to expansion and cracking. Second, the conventional factory mixing method is used, with low mixing speed, poor crushing effect of mixing blades, and poor mixing uniformity of phosphogypsum materials and added materials. Third, the compaction control method is used for rolling and shaping of phosphogypsum materials, and its judgment standard cannot achieve the best compaction and shaping effect of phosphogypsum materials, resulting in low strength and poor stability of phosphogypsum solidified materials, which cannot meet the design standards and purposes of engineering applications.

[0006] Therefore, there is an urgent need to develop targeted high-dosage, high-quality comprehensive application technology for phosphogypsum solid waste. How to overcome the shortcomings of the existing technology is a problem that urgently needs to be solved in this technical field. Summary of the invention

[0007] The purpose of the present invention is to solve the deficiencies of the prior art and to provide a phosphogypsum modified material for highways under a new excitation system and a preparation method and device thereof.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows: The modified phosphogypsum material for highway under the new excitation system includes the following raw materials in percentage by weight: phosphogypsum 80% to 90%, modifier 10% to 20%, totaling 100%; It also includes water, the mass of which is 15% to 18% of the total mass of phosphogypsum and modifier; The modifier includes the following raw materials in parts by weight: 4.8-5.2 parts of calcium oxide, 5.8-6.2 parts of silicon dioxide, 3.9-4.1 parts of aluminum oxide, 9.9-10.1 parts of iron oxide, 39-41 parts of mineral powder, 29-31 parts of tricalcium silicate, 1.9-2.1 parts of calcium carbonate, 0.9-1.1 parts of sodium silicate, 0.9-1.1 parts of coupling agent, 0.48-0.52 parts of iron powder, and 0.48-0.52 parts of rubber powder.

[0009] Furthermore, it is preferred that the coupling agent is an aluminate coupling agent; the activity index of the mineral powder is required to be no less than 75%; the iron powder is required to be no less than 500 mesh; the purity of the rubber powder is required to be no less than 99% and no less than 500 mesh.

[0010] The method for preparing the modified phosphogypsum material for highway under the above-mentioned new excitation system comprises the following steps: Step 1, ingredients: weigh phosphogypsum, modifier and water; Step 2, mixing: stirring the phosphogypsum, modifier and water weighed in step 1 until they are uniformly mixed to obtain a phosphogypsum modified material; wherein the stirring speed is not less than 500 r / min; Step 3, compaction test: test the compaction density control index and moisture content control index of the phosphogypsum modified material. If the compaction control index requirement is not less than 98% of the maximum dry density, and the moisture content control index is within the range of 5mm~10mm, the test is passed and the compliant material is used in the design of highway pavement base structure; If the test fails, the batch of materials cannot be used in the design of highway pavement base structure and should be scrapped.

[0011] Further, preferably, in step 2, the stirring adopts a double S composite full-shaft densely distributed crushing rod type stirring device, and the double S composite full-shaft densely distributed crushing rod type stirring device includes a supporting base; A stirring chamber is installed on the support base; the stirring chamber can rotate relative to the support base; The top of the stirring chamber is provided with a feed and a discharge port; There should be fixed covers on the feed and discharge ports; Also includes electric motors and high-speed rotating machines; The power output end of the electric motor is connected to the power output end of the high-speed rotating machine to provide a power source for the high-speed rotating machine; The stirring chamber is equipped with a high-speed rotating shaft, the other end of which extends out of the stirring chamber and is connected to the power output end of the high-speed rotating machine; the high-speed rotating machine is used to drive the high-speed rotating shaft to rotate; The high-speed rotating shaft inside the mixing chamber is equipped with double S-type mixing blades and full-shaft densely distributed crushing rod-type mixing blades; Further, preferably, a stirring chamber is mounted on the support base via a fixture; The double S stirring blades are symmetrically welded on the high-speed rotating shaft in the stirring chamber, and the full-shaft densely distributed breaking rod stirring blades are welded on the high-speed rotating shaft around the high-speed rotating shaft; Further, preferably, it also includes a stirring time controller, a stirring speed controller, a start-stop controller and an emergency stop button; The stirring time controller is used to control the stirring time; The stirring speed controller is used to control the stirring speed; The start-stop controller is used to control the start and stop of the motor when the motor is powered on; The emergency stop button is used to control the power on and off of the motor.

[0012] Further, preferably, in the compaction test of step 3, the wetness control index is tested by using a phosphogypsum modified material density compaction wetness measuring device; The device for measuring density and moisture content of phosphogypsum modified materials by compaction comprises a pressure-bearing structure 2-1, a contact pressure block and a cylindrical forming mold; The top and bottom of the cylindrical forming mold are both equipped with contact blocks, and a pressure-bearing structure is installed on the side of the contact blocks away from the cylindrical forming mold; The contact pressing block is provided with scale lines; There is also a scale alarm on the contact block; when the edge of the cylindrical forming mold is flush with the scale line of 0cm, the scale alarm will sound an alarm; Four immersion humidity test tubes are arranged symmetrically around the contact pressing block. The immersion humidity test tubes penetrate the contact pressing block, one side of the immersion humidity test tubes extends out of the contact pressing block, and the other side directly contacts the phosphogypsum modified material in the cylindrical forming mold; A filter is provided at the bottom of the immersion humidity test tube, and a water-absorbing and color-changing desiccant is provided inside; A humidity observation line is provided on the humidity test tube.

[0013] Further, preferably, the scale mark on one side of the contact pressure block close to the pressure-bearing structure is 0 cm, and the scale mark on the other side is 5 cm; The 0 cm scale of the wetness observation line is flush with the side of the contact block close to the pressure-bearing structure, and a 1 cm scale range is set upwards.

[0014] The present invention also provides the above-mentioned double S composite full-shaft densely distributed breaking rod type stirring device.

[0015] The present invention also provides a device for measuring the density compaction and moisture content of the phosphogypsum modified material described above.

[0016] Preferably, the modifier comprises the following raw materials in parts by weight: 5 parts of calcium oxide, 6 parts of silicon dioxide, 4 parts of aluminum oxide, 10 parts of iron oxide, 40 parts of mineral powder, 30 parts of tricalcium silicate, 2 parts of calcium carbonate, 1 part of sodium silicate, 1 part of coupling agent, 0.5 parts of iron powder, and 0.5 parts of rubber powder.

[0017] Preferably, the coupling agent is aluminate coupling agent powder. The activity index of the mineral powder is required to be no less than 75%; the activity index of the mineral powder refers to the ratio of the compressive strength of the mortar specimen after the mineral powder and cement are mixed to the compressive strength of the pure cement mortar specimen within the specified age (7 days). The iron powder is required to be no less than 500 mesh (particle size less than 30μm); the purity of the rubber powder is required to be no less than 99%, no less than 500 mesh (particle size less than 30μm).

[0018] In the present invention, the motor provides power, and the high-speed rotary machine forms a higher rotation speed through a mechanical combination of large and small gears under the power of the motor, thereby achieving uniform mixing of the phosphogypsum mixture.

[0019] In the present invention, a stirring chamber is mounted on the support base through a fixture. During the stirring process, the stirring chamber and the fixture are fixed together, and the stirring chamber itself is fixed and cannot rotate. At this time, the high-speed rotating shaft in the stirring chamber can rotate; when the stirring process is completed, the stirring chamber and the fixture are released and can be rotated manually. This is a function that can only be realized after the stirring stops.

[0020] In the present invention, the blades of the double S stirring blades are in an inverted "S" shape, and the combination of two double "S"s presents an inverted "8" shape. The blade shape of the full-axis densely distributed crushing rod type stirring blade is cylindrical. In addition to the double S stirring blades, the other places on the high-speed rotating shaft are all installed with full-axis densely distributed crushing rod type stirring blades.

[0021] In the present invention, the size of the cylindrical molding die is preferably 100 mm and 150 mm in inner diameter, and 200 mm and 250 mm in height. The size of the contact block is preferably 100 mm and 150 mm in diameter, and 50 mm in height.

[0022] The present invention aims at the current status and defects of phosphogypsum materials in highway base layers, proposes a new curing system for phosphogypsum materials, conducts creative research and development from three aspects: modifier materials, mixing devices, and compaction control methods, and invents phosphogypsum modified materials for highways under a new excitation system and a preparation method and device thereof, thereby solving the difficult problem of applying phosphogypsum materials in highway pavement base layers.

[0023] Glossary: (1) Cement-stabilized crushed stone base: It refers to the use of graded crushed stone as aggregate, a certain amount of cementitious materials (mainly cement clinker) and sufficient mortar to fill the gaps between aggregates, and paving and compacting according to the principle of interlocking. Its compaction degree is close to density, and its strength mainly depends on the principle of interlocking between crushed stones. At the same time, there is enough mortar volume to fill the gaps between aggregates. The amount of cement in the cement-stabilized crushed stone base is generally 3% to 6% of the mixture. It is not muddy when it rains, and the surface is solid. It is one of the paving types of road base.

[0024] (2) Unconfined compressive strength: refers to the ultimate strength of the specimen to resist axial pressure without lateral pressure. During the test, the specimen is gradually subjected to axial pressure without lateral restriction (i.e., the surrounding pressure is zero). When the specimen breaks, clear traces of the fracture surface can often be seen on the side of the specimen. The ultimate pressure at the time of test failure is the unconfined compressive strength.

[0025] (3) Wetness: This is a new concept proposed by the present invention. It refers to a measurement indicator that uses certain technical means to test the amount of water squeezed out of the phosphogypsum mixture during the compaction process. It is used to directly evaluate the rationality of the water content in the phosphogypsum asphalt mixture and indirectly evaluate the compaction degree and curing degree of the phosphogypsum mixture.

[0026] In the present invention, the modifier comprises the following raw materials: calcium oxide (CaO), silicon dioxide (SiO2), aluminum oxide (Al2O3), ferric oxide (Fe2O3), mineral powder, tricalcium silicate (3CaO·SiO2), calcium carbonate (CaCO3), sodium silicate (Na2O·nSiO2), coupling agent, iron powder, and rubber powder.

[0027] In the present invention, the stirring chamber can rotate, and the axis of rotation is parallel to the horizontal plane; when feeding, it is preferred that the stirring chamber mouth faces upward; when discharging, it is preferred that the stirring chamber rotates about 45 degrees and discharges at an angle.

[0028] In the present invention, preferably, all scales involved have a dimensional accuracy of 1 mm. In the scale ranges between 0-5 cm and 0-1 cm, the dimensional accuracy is 1 mm.

[0029] Compared with the prior art, the present invention has the following beneficial effects: The present invention creatively proposes a new modifier for modifying phosphogypsum solid waste materials and achieving the strength and stability required by the project, avoiding the shortcomings of insufficient strength and poor stability caused by cement-based materials solidifying phosphogypsum materials. The new modifier can not only meet the project requirements within the prescribed growth period (generally requiring the 7-day unconfined compressive strength to be no less than 4 MPa), but also shows excellent strength growth and stability improvement advantages in long-term performance development. It is highly environmentally friendly, has no pollution to the environment, soil, and water bodies, and has good economy without increasing the overall cost of the project.

[0030] The present invention proposes a high-speed (generally requiring a rotation speed of not less than 500r / min), efficient, crushing and uniform mixing method and device, abandoning the disadvantages of low conventional stirring speed (the existing stirring speed is generally about 60r / min), poor blade crushing ability and uneven mixing, and innovatively proposes a double S composite full-axis dense crushing rod superimposed high-speed rotation function phosphogypsum material stirring method, by greatly improving the stirring speed, adding full-axis dense crushing rods and blades, increasing the crushing degree of the phosphogypsum material in the mixing process, reducing the agglomeration phenomenon in the phosphogypsum material, and increasing the mixing uniformity of the phosphogypsum material with the added modifier and water, which is more conducive to the solidification and stability of the phosphogypsum material.

[0031] The present invention proposes a new compaction control standard and device, which solves the problem that the solidification quality of phosphogypsum materials is poor due to the current control of compaction density. On the basis of meeting the original compaction density control index (i.e. not less than the original compaction), the wetness control index of the phosphogypsum modified material is added, that is, after adding the modifier and water to the phosphogypsum material, the phosphogypsum modified material is formed. During the indoor compaction process, the water pressure out of the water outlet is observed. When the outflowing water just soaks to the specified scale, it means that the compaction meets the engineering requirements. At this time, the solidification and stability of the phosphogypsum material can achieve the best effect. If too much, too little or no water flows out, it means that the wetness is too large or too small, and the best effect of the strength index and stability index after the phosphogypsum is not achieved. When the phosphogypsum material is compacted on site, the wetness control method creatively proposed by the present invention is adopted, which can effectively improve the various performance indicators of the phosphogypsum material after solidification, and can reduce the amount of modifier materials, saving the overall cost.

[0032] Compared with existing data, the present invention has outstanding advantages in the strength formation, water stability and volume stability of phosphogypsum road base. Among them, the 7d unconfined compressive strength is stably increased by about 40% compared with conventional cement, and the long-term strength enhancement is greater. In addition, compared with the existing conventional technology, the water stability and volume stability have greater advantages. In the long-term immersion test, there is no cracking, no expansion, and no dispersion. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of a double S composite full-shaft densely distributed crushing rod type stirring device; Figure 2 It is a schematic diagram of the full-axis densely distributed crushing rod type stirring blades; Figure 3 It is a schematic diagram of a device for measuring density and moisture content of phosphogypsum modified materials by compaction; Figure 4 This is a schematic diagram of a humidity test tube; Figure 5 Schematic diagram of the bottom filter structure. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with embodiments.

[0035] Those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the art or the product specifications are used. If the manufacturer of the materials or equipment used is not specified, they are all conventional products that can be purchased.

[0036] It will be understood by those skilled in the art that, unless expressly stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" to another element, it may be directly connected to the other element, or there may be intermediate elements. The term "and / or" used herein includes any unit and all combinations of one or more associated listed items.

[0037] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two. The terms "inside", "upper", "lower", etc., indicating positions or state relationships, are based on the positions or state relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operate in a specific position, and therefore cannot be understood as limiting the present invention.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "provided with" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention will be understood according to specific circumstances.

[0039] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the field to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein. Example 1

[0040] The phosphogypsum modified material for highway under the new excitation system is characterized by comprising the following raw materials in percentage by weight: 85% phosphogypsum, 15% modifier, a total of 100%; It also includes water, the mass of which is 15% of the total mass of phosphogypsum and modifier; The modifier includes the following raw materials in parts by weight: 5 parts of calcium oxide, 5.9 parts of silicon dioxide, 4 parts of aluminum oxide, 10 parts of iron oxide, 40 parts of mineral powder, 30 parts of tricalcium silicate, 2 parts of calcium carbonate, 1 part of sodium silicate, 1 part of coupling agent, 0.49 parts of iron powder, and 0.51 parts of rubber powder.

[0041] The method for preparing the modified phosphogypsum material for highway under the new excitation system of this embodiment comprises the following steps: Step 1, ingredients: weigh phosphogypsum, modifier and water; Step 2, mixing: stirring the phosphogypsum, modifier and water weighed in step 1 until they are uniformly mixed to obtain a phosphogypsum modified material; wherein the stirring speed is not less than 500 r / min; Step 3, compaction test: test the compaction density control index and moisture content control index of the phosphogypsum modified material. If the compaction control index requirement is not less than 98% of the maximum dry density, and the moisture content control index is within the range of 5mm~10mm, the test is passed and the compliant material is used in the design of highway pavement base structure; If the test fails, the batch of materials cannot be used in the design of highway pavement base structure and should be scrapped. Example 2

[0042] The phosphogypsum modified material for highway under the new excitation system is characterized by comprising the following raw materials in percentage by weight: 80% phosphogypsum, 20% modifier, a total of 100%; It also includes water, the mass of which is 15% of the total mass of phosphogypsum and modifier; The modifier includes the following raw materials in parts by weight: 4.8 parts of calcium oxide, 5.8 parts of silicon dioxide, 3.9 parts of aluminum oxide, 9.9 parts of iron oxide, 39 parts of mineral powder, 29 parts of tricalcium silicate, 1.9 parts of calcium carbonate, 0.9 parts of sodium silicate, 0.9 parts of coupling agent, 0.48 parts of iron powder, and 0.48 parts of rubber powder.

[0043] The coupling agent used is aluminate coupling agent; the activity index of the mineral powder is required to be no less than 75%; the iron powder is required to be no less than 500 mesh; the purity of the rubber powder is required to be no less than 99% and no less than 500 mesh.

[0044] The method for preparing the modified phosphogypsum material for highway under the new excitation system of this embodiment comprises the following steps: Step 1, ingredients: weigh phosphogypsum, modifier and water; Step 2, mixing: stirring the phosphogypsum, modifier and water weighed in step 1 until they are uniformly mixed to obtain a phosphogypsum modified material; wherein the stirring speed is not less than 500 r / min; Step 3, compaction test: test the compaction density control index and moisture content control index of the phosphogypsum modified material. If the compaction control index requirement is not less than 98% of the maximum dry density, and the moisture content control index is within the range of 5mm~10mm, the test is passed and the compliant material is used in the design of highway pavement base structure; If the test fails, the batch of materials cannot be used in the design of highway pavement base structure and should be scrapped.

[0045] like Figure 1~Figure 5 As shown, in step 2, a double S composite full-shaft densely distributed crushing rod type stirring device is used for stirring, and the double S composite full-shaft densely distributed crushing rod type stirring device includes a supporting base 1-13; A stirring chamber 1-8 is installed on the supporting base 1-13; the stirring chamber 1-8 can rotate relative to the supporting base 1-13; The top of the stirring chamber 1-8 is provided with a feed and discharge port 1-6; There should be fixed covers 1-7 on the feed and discharge ports 1-6; Also includes a motor 1-1 and a high-speed rotating machine 1-2; The power output end of the motor 1-1 is connected to the power output end of the high-speed rotating machine 1-2 to provide a power source for the high-speed rotating machine 1-2; The stirring chamber 1-8 is equipped with a high-speed rotating shaft 1-3, the other end of which extends out of the stirring chamber 1-8 and is connected to the power output end of the high-speed rotating machine 1-2; the high-speed rotating machine 1-2 is used to drive the high-speed rotating shaft 1-3 to rotate; The high-speed rotating shaft 1-3 inside the stirring cavity 1-8 is equipped with double S stirring blades 1-4 and full-shaft densely distributed crushing rod type stirring blades 1-5.

[0046] In step 3, during the compaction test, the moisture content control index is tested using a phosphogypsum modified material density compaction moisture content measuring device; The device for measuring density and moisture content of phosphogypsum modified materials by compaction comprises a pressure-bearing structure 2-1, a contact block 2-2 and a cylindrical forming mold 2-9; The top and bottom of the cylindrical forming mold 2-9 are both installed with contact blocks 2-2, and the side of the contact blocks 2-2 away from the cylindrical forming mold 2-9 is installed with a pressure-bearing structure 2-1; A scale line 2-3 is provided on the contact pressing block 2-2; There is also a scale alarm 2-4 on the contact pressing block 2-2; when the edge of the cylindrical forming mold 2-9 is flush with the scale line 2-3 at 0cm, the scale alarm 2-4 will sound an alarm; Four immersion humidity test tubes 2-5 are centrally symmetrically arranged around the contact block 2-2. The immersion humidity test tubes 2-5 penetrate the contact block 2-2, one side of which extends out of the contact block 2-2, and the other side directly contacts the phosphogypsum modified material in the cylindrical forming mold 2-9; A filter screen 2-6 is provided at the bottom of the immersion humidity test tube 2-5, and a water-absorbing color-changing desiccant 2-8 is provided inside; A humidity observation line 2-7 is provided on the humidity test tube 2-5. Example 3

[0047] The phosphogypsum modified material for highway under the new excitation system is characterized by comprising the following raw materials in percentage by weight: 90% phosphogypsum, 10% modifier, and a total of 100%; It also includes water, the mass of which is 18% of the total mass of phosphogypsum and modifier; The modifier includes the following raw materials in parts by weight: 5.2 parts of calcium oxide, 6.2 parts of silicon dioxide, 4.1 parts of aluminum oxide, 10.1 parts of iron oxide, 41 parts of mineral powder, 31 parts of tricalcium silicate, 2.1 parts of calcium carbonate, 1.1 parts of sodium silicate, 1.1 parts of coupling agent, 0.52 parts of iron powder, and 0.52 parts of rubber powder.

[0048] The coupling agent used is aluminate coupling agent; the activity index of the mineral powder is required to be no less than 75%; the iron powder is required to be no less than 500 mesh; the purity of the rubber powder is required to be no less than 99% and no less than 500 mesh.

[0049] The method for preparing the modified phosphogypsum material for highway under the new excitation system of this embodiment comprises the following steps: Step 1, ingredients: weigh phosphogypsum, modifier and water; Step 2, mixing: stirring the phosphogypsum, modifier and water weighed in step 1 until they are uniformly mixed to obtain a phosphogypsum modified material; wherein the stirring speed is not less than 500 r / min; Step 3, compaction test: test the compaction density control index and moisture content control index of the phosphogypsum modified material. If the compaction control index requirement is not less than 98% of the maximum dry density, and the moisture content control index is within the range of 5mm~10mm, the test is passed and the compliant material is used in the design of highway pavement base structure; If the test fails, the batch of materials cannot be used in the design of highway pavement base structure and should be scrapped.

[0050] like Figure 1~Figure 5 As shown, in step 2, a double S composite full-shaft densely distributed crushing rod type stirring device is used for stirring, and the double S composite full-shaft densely distributed crushing rod type stirring device includes a supporting base 1-13; A stirring chamber 1-8 is installed on the supporting base 1-13; the stirring chamber 1-8 can rotate relative to the supporting base 1-13; The top of the stirring chamber 1-8 is provided with a feed and discharge port 1-6; There should be fixed covers 1-7 on the feed and discharge ports 1-6; Also includes a motor 1-1 and a high-speed rotating machine 1-2; The power output end of the motor 1-1 is connected to the power output end of the high-speed rotating machine 1-2 to provide a power source for the high-speed rotating machine 1-2; The stirring chamber 1-8 is equipped with a high-speed rotating shaft 1-3, the other end of which extends out of the stirring chamber 1-8 and is connected to the power output end of the high-speed rotating machine 1-2; the high-speed rotating machine 1-2 is used to drive the high-speed rotating shaft 1-3 to rotate; The high-speed rotating shaft 1-3 inside the stirring cavity 1-8 is equipped with double S stirring blades 1-4 and full-shaft densely distributed crushing rod type stirring blades 1-5.

[0051] In step 3, during the compaction test, the moisture content control index is tested using a phosphogypsum modified material density compaction moisture content measuring device; The device for measuring density and moisture content of phosphogypsum modified materials by compaction comprises a pressure-bearing structure 2-1, a contact block 2-2 and a cylindrical forming mold 2-9; The top and bottom of the cylindrical forming mold 2-9 are both installed with contact blocks 2-2, and the side of the contact blocks 2-2 away from the cylindrical forming mold 2-9 is installed with a pressure-bearing structure 2-1; A scale line 2-3 is provided on the contact pressing block 2-2; There is also a scale alarm 2-4 on the contact pressing block 2-2; when the edge of the cylindrical forming mold 2-9 is flush with the scale line 2-3 at 0cm, the scale alarm 2-4 will sound an alarm; Four immersion humidity test tubes 2-5 are centrally symmetrically arranged around the contact block 2-2. The immersion humidity test tubes 2-5 penetrate the contact block 2-2, one side of which extends out of the contact block 2-2, and the other side directly contacts the phosphogypsum modified material in the cylindrical forming mold 2-9; A filter screen 2-6 is provided at the bottom of the immersion humidity test tube 2-5, and a water-absorbing color-changing desiccant 2-8 is provided inside; A humidity observation line 2-7 is provided on the humidity test tube 2-5.

[0052] A stirring chamber 1-8 is mounted on the support base 1-13 via a fixture 1-14; The double S stirring blades are symmetrically welded on the high-speed rotating shaft 1-3 in the stirring chamber 1-8, and the full-shaft densely distributed breaking rod type stirring blades 1-5 are welded on the high-speed rotating shaft 1-3 around the high-speed rotating shaft 1-3; The scale line 2-3 on one side of the contact block 2-2 close to the pressure-bearing structure 2-1 is 0 cm, and the scale line 2-3 on the other side is 5 cm; The 0 cm scale of the wetness observation line 2-7 is flush with the side of the contact block 2-2 close to the pressure-bearing structure 2-1, and a 1 cm scale range is set upward. Example 4

[0053] The phosphogypsum modified material for highway under the new excitation system is characterized by comprising the following raw materials in percentage by weight: 83% phosphogypsum, 17% modifier, a total of 100%; It also includes water, the mass of which is 17% of the total mass of phosphogypsum and modifier; The modifier includes the following raw materials in parts by weight: 5 parts of calcium oxide, 6 parts of silicon dioxide, 4 parts of aluminum oxide, 10 parts of iron oxide, 40 parts of mineral powder, 30 parts of tricalcium silicate, 2 parts of calcium carbonate, 1 part of sodium silicate, 1 part of coupling agent, 0.5 parts of iron powder, and 0.5 parts of rubber powder.

[0054] The coupling agent used is aluminate coupling agent; the activity index of the mineral powder is required to be no less than 75%; the iron powder is required to be no less than 500 mesh; the purity of the rubber powder is required to be no less than 99% and no less than 500 mesh.

[0055] The method for preparing the modified phosphogypsum material for highway under the new excitation system of this embodiment comprises the following steps: Step 1, ingredients: weigh phosphogypsum, modifier and water; Step 2, mixing: stirring the phosphogypsum, modifier and water weighed in step 1 until they are uniformly mixed to obtain a phosphogypsum modified material; wherein the stirring speed is not less than 500 r / min; Step 3, compaction test: test the compaction density control index and moisture content control index of the phosphogypsum modified material. If the compaction control index requirement is not less than 98% of the maximum dry density, and the moisture content control index is within the range of 5mm~10mm, the test is passed and the compliant material is used in the design of highway pavement base structure; If the test fails, the batch of materials cannot be used in the design of highway pavement base structure and should be scrapped.

[0056] like Figure 1~Figure 5 As shown, in step 2, a double S composite full-shaft densely distributed crushing rod type stirring device is used for stirring, and the double S composite full-shaft densely distributed crushing rod type stirring device includes a supporting base 1-13; A stirring chamber 1-8 is installed on the supporting base 1-13; the stirring chamber 1-8 can rotate relative to the supporting base 1-13; The top of the stirring chamber 1-8 is provided with a feed and discharge port 1-6; There should be fixed covers 1-7 on the feed and discharge ports 1-6; Also includes a motor 1-1 and a high-speed rotating machine 1-2; The power output end of the motor 1-1 is connected to the power output end of the high-speed rotating machine 1-2 to provide a power source for the high-speed rotating machine 1-2; The stirring chamber 1-8 is equipped with a high-speed rotating shaft 1-3, the other end of which extends out of the stirring chamber 1-8 and is connected to the power output end of the high-speed rotating machine 1-2; the high-speed rotating machine 1-2 is used to drive the high-speed rotating shaft 1-3 to rotate; The high-speed rotating shaft 1-3 inside the stirring cavity 1-8 is equipped with double S stirring blades 1-4 and full-shaft densely distributed crushing rod type stirring blades 1-5.

[0057] In step 3, during the compaction test, the moisture content control index is tested using a phosphogypsum modified material density compaction moisture content measuring device; The device for measuring density and moisture content of phosphogypsum modified materials by compaction comprises a pressure-bearing structure 2-1, a contact block 2-2 and a cylindrical forming mold 2-9; The top and bottom of the cylindrical forming mold 2-9 are both installed with contact blocks 2-2, and the side of the contact blocks 2-2 away from the cylindrical forming mold 2-9 is installed with a pressure-bearing structure 2-1; A scale line 2-3 is provided on the contact pressing block 2-2; There is also a scale alarm 2-4 on the contact pressing block 2-2; when the edge of the cylindrical forming mold 2-9 is flush with the scale line 2-3 at 0cm, the scale alarm 2-4 will sound an alarm; Four immersion humidity test tubes 2-5 are centrally symmetrically arranged around the contact block 2-2. The immersion humidity test tubes 2-5 penetrate the contact block 2-2, one side of which extends out of the contact block 2-2, and the other side directly contacts the phosphogypsum modified material in the cylindrical forming mold 2-9; A filter screen 2-6 is provided at the bottom of the immersion humidity test tube 2-5, and a water-absorbing color-changing desiccant 2-8 is provided inside; A humidity observation line 2-7 is provided on the humidity test tube 2-5.

[0058] A stirring chamber 1-8 is mounted on the support base 1-13 via a fixture 1-14; The double S stirring blades are symmetrically welded on the high-speed rotating shaft 1-3 in the stirring chamber 1-8, and the full-axis densely distributed breaking rod type stirring blades 1-5 are welded on the high-speed rotating shaft 1-3 around the high-speed rotating shaft 1-3; it also includes a stirring time controller 1-9, a stirring speed controller 1-10, a start-stop controller 1-11 and an emergency stop button 1-12; The stirring time controller 1-9 is used to control the stirring time; Stirring speed controller 1-10 is used to control the stirring speed; The start-stop controller 1-11 is used to control the start and stop of the motor 1-1 when the motor 1-1 is powered on; The emergency stop button 1-12 is used to control the power on and off of the motor 1-1.

[0059] The scale line 2-3 on one side of the contact block 2-2 close to the pressure-bearing structure 2-1 is 0 cm, and the scale line 2-3 on the other side is 5 cm; The 0 cm scale of the wetness observation line 2-7 is flush with the side of the contact block 2-2 close to the pressure-bearing structure 2-1, and a 1 cm scale range is set upward. Example 5

[0060] The invention points that need to be protected mainly include three major aspects: the first is the new modifier material; the second is the high-speed, high-efficiency crushing uniform stirring method and device; the third is the creatively proposed method and device for controlling the compaction degree by soaking moisture. The specific invention points are as follows: (1) The present invention creatively proposes a new type of modifier material. The biggest difference between the present invention and cement-based curing materials is that the material has high early strength. Considering the comprehensive economic performance to meet the engineering requirements (compared with the existing highway base materials, the comprehensive engineering cost is not increased), the present invention not only meets the requirements of the seven-day unconfined compressive strength of the highway base (generally controlled at 5 MPa), but also has a large increase in strength in the later stage, strong water stability, good volume stability, no expansion and cracking, and is environmentally friendly.

[0061] The main materials of the new modifier are calcium oxide (CaO), silicon dioxide (SiO2), aluminum oxide (Al2O3), ferric oxide (Fe2O3), mineral powder, tricalcium silicate (3CaO·SiO2), calcium carbonate (CaCO3), sodium silicate (Na2O·nSiO2), coupling agent, iron powder and rubber powder, with a fineness of not less than 1000 mesh. The new modifier uses the principle of stimulating phosphogypsum (the main component is calcium sulfate dihydrate (CaSO4·2H2O)) to cause a petrochemical reaction to produce a basalt-like texture. At the same time, iron powder is added to control the growth of early strength, and rubber powder is compounded to fill the pores inside the phosphogypsum. Since the microscopic morphology of phosphogypsum itself presents a plate-like crystal arrangement and a large internal porosity, rubber powder can be used to fill its internal pores to enhance the strength and stability of the phosphogypsum material. In addition, the rubber powder itself has certain elastic properties. Adding rubber powder can effectively improve the elastic properties of the phosphogypsum modified material, prevent the phosphogypsum modified material from shrinking and expanding and cracking, and improve the performance of the phosphogypsum modified material.

[0062] The production ratio of phosphogypsum curing materials generally requires that the mass ratio of phosphogypsum itself should not be less than 80%, and its mass can be controlled between 80% and 90%. The mass of new modifier materials should be controlled between 10% and 20%, and the mass of water should be 15% to 18% of the total amount of phosphogypsum and new modifiers. Since phosphogypsum materials are highly sensitive to water, too high a water content will lead to a decrease in the compaction degree of phosphogypsum, while too low a water content will lead to poor excitation effect of phosphogypsum materials, which is not conducive to phosphogypsum curing. Therefore, in actual projects, the water content should be strictly controlled, and neither excessive nor insufficient water should be used. The water content should be controlled at 15% to 18% of the total amount of phosphogypsum and modifiers.

[0063] The following is the phosphogypsum curing mix ratio with better engineering application effect: Mix ratio 1: phosphogypsum: modifier = 10:90, water content is 15% of the total amount of phosphogypsum and modifier; Mix ratio 2: phosphogypsum: modifier = 15:85, water content is 16% of the total amount of phosphogypsum and modifier; Mix ratio 3: phosphogypsum: modifier = 17:83, the water content is 17% of the total amount of phosphogypsum and modifier.

[0064] Mix ratio 4: phosphogypsum: modifier = 20:80, the water content is 18% of the total amount of phosphogypsum and modifier.

[0065] (2) The present invention proposes a high-speed (generally requiring a rotation speed of not less than 500 r / min), high-efficiency, crushing-type uniform mixing method and device, which makes up for the shortcomings of the traditional mixing method of low speed, no crushing, and uneven mixing. It combines high-speed rotation with double S composite full-axis densely distributed crushing rod-type mixing blades to solve the problem of internal agglomeration of phosphogypsum materials. In addition, under the creative mixing method combining high-speed rotation with densely distributed rod-type crushing mixing blades, the phosphogypsum material is mixed more evenly with the added modifier and water, which is beneficial to the improvement and stabilization of the comprehensive performance of the phosphogypsum material after solidification, especially its strength and volume stability are greatly improved.

[0066] Combination Figure 1 and Figure 2 , the invention double S composite full-axis densely distributed crushing rod type stirring device is described as follows, its main parts are divided into: 1-1 electric motor, 1-2 high-speed rotating machine, 1-3 high-speed rotating shaft, 1-4 double S stirring blades, 1-5 full-axis densely distributed crushing rod type stirring blades, 1-6 feeding and discharging ports, 1-7 fixed cover, 1-8 stirring chamber, 1-9 stirring time controller, 1-10 stirring speed controller, 1-11 start-stop controller, 1-12 emergency stop button, 1-13 support base, 1-14 fixer.

[0067] The motor 1-1 is used to provide a power source for the high-speed rotating machine 1-2. It is a variable frequency configuration and can control the rotation speed by adjusting the frequency as needed.

[0068] The high-speed rotating machine 1-2 is used to provide high-speed rotation function, has sufficient strength and rigidity, can stably operate under high-speed rotation conditions, and its rotation speed is required to reach 500r / min, and the speed can be controlled by adjustment.

[0069] The high-speed rotating shaft 1-3 is used to connect the high-speed rotating machine 1-2 and the mixing blades, transmit the high-speed rotating function of the high-speed rotating machine 1-2 to the mixing blades, drive the double S mixing blades 1-4 and the full-axis densely distributed crushing rod type mixing blades 1-5 to produce high-speed rotation function, have sufficient strength and rigidity, and operate stably under high-speed rotation conditions.

[0070] The double S stirring blades 1-4 are used to stir the phosphogypsum material, so that the phosphogypsum material produces a circular rolling in the longitudinal direction and a circular rolling left and right in the horizontal direction, so as to achieve uniform stirring in the horizontal direction. The double S stirring blades 1-4 have sufficient strength and rigidity and can operate stably under high-speed rotation conditions.

[0071] The entire shaft is densely covered with crushing rod-type stirring blades 1-5, which are used to stir the phosphogypsum material and break the lumps in the phosphogypsum material, so that the phosphogypsum material is stirred more evenly. By utilizing the force of high-speed rotation, the crushing rod-type stirring blades densely distributed throughout the shaft break the lumps in the phosphogypsum, so that the phosphogypsum, modifier and water are stirred more evenly, and the overall performance of the phosphogypsum modified material is improved. It has sufficient strength and rigidity and operates stably under high-speed rotation conditions.

[0072] The feed and discharge ports 1-6 are used to add phosphogypsum, modifier and water into the mixing chamber, and are also used to discharge the mixed material after uniform mixing. They are generally square in structure and have reasonable size to meet the requirements of feed and discharge.

[0073] The fixed cover 1-7 is used to close the feed and discharge ports 1-6. The fixed cover is opened when adding materials and closed when mixing to prevent dust and accidents during mixing. It has sufficient strength and rigidity and is tightly sealed with the feed and discharge ports.

[0074] The stirring chamber 1-8 is used to contain phosphogypsum, modifier and water, and provides space for stirring the mixed materials to meet the stirring requirements of the mixed materials. It has sufficient strength and rigidity and can operate stably under high-speed rotation conditions. The stirring chamber is connected to the support base during the stirring process and is fixed. When the stirring is completed, the fixed valve can be loosened and the stirring chamber can be rotated to realize the discharge of the mixed material.

[0075] The mixing time controller 1-9 is used to control the mixing time of the phosphogypsum mixture, which can realize continuous control and is generally controlled to 90~120s.

[0076] The stirring speed controller 1-10 is used to control the stirring speed of the phosphogypsum mixture, and can realize stepless speed regulation, that is, it can be adjusted from 0 to the maximum speed. During the stirring process of the phosphogypsum mixture, high-speed rotation is required, and the control speed is not less than 500r / min.

[0077] The start-stop controller 1-11 is used to control the start and stop of the mixing device.

[0078] Emergency stop buttons 1-12 are used to stop all operations of the stirring device in an emergency.

[0079] The support base 1-13 is used to support the entire stirring device and has sufficient strength and rigidity to operate stably under high-speed rotation conditions without moving.

[0080] The fixer 1-14 is used to fix the stirring chamber 1-8 and the supporting base 1-13 together to ensure that the stirring chamber does not rotate during high-speed stirring and has sufficient strength and rigidity.

[0081] (3) The present invention creatively proposes a new compaction control standard and device for phosphogypsum modified materials, which solves the problem that the current compaction control mainly relies on the compaction density, resulting in poor solidification quality of phosphogypsum. On the basis of meeting the original compaction density control index (i.e. not less than the original compaction), a moisture content control index of the phosphogypsum-modifier-water composite material is added, that is, after the modifier and water are added to the phosphogypsum material, the composite material is formed and its internal moisture is squeezed out during the indoor compaction process. When the squeezed out moisture is soaked to the specified scale, it means that the compaction meets the engineering requirements. At this time, the solidification and stability of the phosphogypsum material can achieve the best effect. If too much water flows out, too little water flows out, or even no water flows out, it means that the moisture content is too large or too small, and the optimal effect of the strength index and stability index after the phosphogypsum is cured cannot be achieved. When the phosphogypsum-modifier-water composite material is compacted on site, the moisture control method creatively proposed by the present invention is adopted, which not only satisfies the compaction effect of the phosphogypsum material, but also satisfies the moisture required for the solidification of the phosphogypsum, avoiding the disadvantage of using the density compaction control index alone and ignoring the control index of the moisture required for the solidification of the phosphogypsum. The density compaction and moisture dual control indexes are used on site, taking into account the requirements of the compaction and solidification hydration of the phosphogypsum material, and can effectively improve the various performance indicators of the phosphogypsum material after solidification. When the density compaction and moisture dual control standards are used, generally under the influence of moisture, the overall compaction value will be increased, and the phenomenon of overpressure (exceeding the specified compaction) will occur, which has a beneficial effect on the phosphogypsum base material. This is related to the heavy-duty road roller used on site. From the perspective of comprehensive performance, the increase in compaction can appropriately reduce the amount of modifier materials and save the comprehensive cost while meeting the strength and stability requirements of the phosphogypsum highway base.

[0082] Combined with Figure 3 The invention of the density compaction and moisture content determination device for phosphogypsum modified materials is described as follows, and its main parts are divided into: 2-1 pressure-bearing structure, 2-2 contact pressure block, 2-3 scale line, 2-4 scale alarm, 2-5 moisture content test tube, 2-6 filter screen, 2-7 moisture content observation line, 2-8 water-absorbing and color-changing desiccant, and 2-9 cylindrical molding mold.

[0083] The pressure-bearing structure 2-1 is used for directly contacting the pressure applied by the press machine, is connected to the contact block 2-2, and transmits the pressure to the contact block 2-2 to achieve compaction of the phosphogypsum material. The upper part is a circular block, and the lower part is a cylindrical block, forming a "T" structure. The pressure-bearing structure is higher than the contact block by a certain distance, leaving enough height space for the operation of the humidity test tube, and has sufficient strength and rigidity, and does not deform under heavy pressure.

[0084] The contact block 2-2 is connected to the pressure-bearing structure 2-1, and directly contacts the uniformly stirred mixture of phosphogypsum, modifier and water, and compacts the mixture to a specified density through pressure. Graduation lines 2-3 are arranged on the left and right sides of the contact block to control the vertical displacement of the block. Four immersion humidity test tubes 2-5 are arranged around the contact block 2-2. The immersion humidity test tube 2-5 runs through the contact block 2-2, one side extends out of the contact block 2-2 to a certain height, and the other side directly contacts the phosphogypsum mixture. A filter screen 2-6 is arranged at the bottom to prevent the phosphogypsum mixture from pouring into the test tube.

[0085] The scale line 2-3 is used to mark the vertical displacement value that the contact block 2-2 needs to be pressed into, and to control the depth of the contact block 2-2 pressed into the phosphogypsum mixture. The total length of the scale line is 5 cm, and the scale line is subdivided into millimeter levels. The scale line is set so that the top of the contact block 2-2 (the side that does not directly contact the phosphogypsum mixture) is marked as the 0 scale line, and the bottom of the contact block (the side that directly contacts the phosphogypsum mixture) is marked as the 5 cm scale line. The middle is set from 0 to 5 cm in sequence according to the standard scale. The benefit of setting the scale line in this way is that it is easy to read the depth that the contact block should be pressed into the phosphogypsum mixture, and it is convenient to control the vertical movement distance of the contact block.

[0086] The scale alarm 2-4 is used to provide an alarm for vertical displacement. When the contact block moves to the specified scale, that is, when the edge of the cylindrical forming mold 2-9 touches the top of the scale line 2-3 (on the side that does not directly contact the phosphogypsum mixture), the scale alarm 2-4 sounds an alarm, indicating that the test vertical displacement has reached the specified value. Since the contact block 2-2 is divided into two pieces, the upper and lower pieces are placed in the cylindrical forming mold at the same time, and the pressure compaction is carried out at the same time, the scale alarm 2-4 is also divided into two parts, the upper and lower parts of the scale alarm 2-4 are connected. When only the upper or lower side alarm sounds an alarm, the compaction process can continue. When the upper and lower parts sound an alarm at the same time, it means that the compaction test has reached the specified vertical displacement value, and the test should be stopped at this time.

[0087] The moisture test tube 2-5 is used to test the moisture wetting height squeezed out of the phosphogypsum mixture during the compaction process, so as to determine whether the compaction degree of the phosphogypsum mixture and the moisture required for curing have reached a reasonable ratio range. It is filled with a color-changing desiccant, and a filter 2-6 is provided at the bottom (the side directly in contact with the phosphogypsum mixture) to prevent the phosphogypsum mixture from pouring into the test tube. One side of the moisture test tube 2-5 is in direct contact with the phosphogypsum mixture, and the other side penetrates the contact block 2-2 and extends out of the contact block 2-2 to a certain height to set a 1cm effective observation scale, with the 0 scale line at the bottom, flush with the top surface of the contact block 2-2 (the side not in direct contact with the phosphogypsum mixture), and the 1cm scale line at the top, and the middle scale lines are set in accordance with the standard scale in turn, set to the millimeter level. During the compaction process, when the color-changing desiccant in the immersion humidity test tube 2-5 absorbs the squeezed water in the phosphogypsum mixture and changes color, and reaches the 5mm scale value position of the immersion humidity test tube 2-5 scale line, it means that its immersion humidity has reached the best effect, that is, the moisture control effect in the phosphogypsum mixture is the best. When the color-changing height of the desiccant is lower than the 0 scale line of the immersion humidity test tube, it means that the moisture control in the phosphogypsum mixture is low. When the color-changing height of the desiccant is higher than the 1cm scale line of the immersion humidity test tube, it means that the moisture control in the phosphogypsum mixture is high. Both lower and higher moisture control amounts will affect the performance of the phosphogypsum mixture. In the engineering application process, the height of the desiccant absorbing the squeezed water in the phosphogypsum mixture and causing the color change is controlled within the range of 0-1cm of the immersion humidity test tube, so that the strength and stability of the phosphogypsum mixture after compaction are better.

[0088] The filter screen 2-6, as the bottom structure of the moisture test tube, is used to prevent the phosphogypsum mixture from being poured into the moisture test tube, and can allow moisture to flow into the moisture test tube, and has sufficient anti-deformation ability.

[0089] The moisture observation line 2-7, as the main observation part of the moisture test tube, is used to observe the height of the desiccant absorbing moisture and changing color, so as to control the compaction degree and curing moisture amount of the phosphogypsum mixture. The moisture observation line is set with an effective observation length of 1 cm, wherein the 0 scale line is at the bottom, flush with the top surface of the contact block 2-2 (the side that does not directly contact the phosphogypsum mixture), the 1 cm scale line is at the top, and the middle scale lines are set in accordance with the standard scale in turn, and are set to the millimeter level.

[0090] Water-absorbing color-changing desiccant 2-8 is used to absorb the moisture squeezed out of the phosphogypsum mixture during the compaction process. The water-absorbing color-changing desiccant is generally a silica gel desiccant, and its main component is amorphous silicon dioxide, which is a highly adsorbent material. It is blue before absorbing water and red after absorbing water. The amount of water in the phosphogypsum mixture can be judged by the color change after absorbing water, thereby judging the quality of the performance of the phosphogypsum after solidification.

[0091] The cylindrical forming mold 2-9 is used to contain and compact the phosphogypsum mixture. It is hollow without a cover or bottom. The contact block in the phosphogypsum modified material density compaction-wetness determination device can be placed in the cylindrical forming mold. The phosphogypsum mixture is filled into the cylindrical forming mold, and under a certain pressure, a sample of a specified size (generally a cylindrical sample with a size of φ100mm and a height of 100mm after molding) is formed, which has sufficient strength and rigidity.

[0092] The implementation scheme of the present invention is divided into three steps, namely batching, mixing and compacting. First, the batching is mainly the mix ratio between phosphogypsum, modifier and water. According to the designed mix ratio, a certain mass of phosphogypsum, modifier and water are weighed. The modifier adopts a new type of modifier, and the weighing is ready for use. The batching is completed.

[0093] The double S composite full-axis densely distributed broken rod type stirring device is firmly fixed on the ground by the support base 1-13, and the stirring chamber 1-8 is fixed in a stable position by the fixer 1-14 so that it does not rotate. Open the feed and discharge ports 1-6, add the weighed phosphogypsum, modifier and water into the stirring chamber 1-8 in turn, and then use the fixed cover 1-7 to close the feed and discharge ports 1-6, set the predetermined stirring time and stirring speed by the stirring time controller 1-9 and the stirring speed controller 1-10 respectively, press the start-stop controller 1-11 to start the double S composite full-axis densely distributed broken rod type stirring device, and drive the double S stirring blades 1-4 and the full-axis densely distributed broken rod type stirring blades 1-5 by the motor 1-1, the high-speed rotating machine 1-2, and the high-speed rotating shaft 1-3 to start stirring the phosphogypsum, modifier, and water mixture. When encountering an emergency, press the emergency stop button 1-12 to stop all operations of the device. When the stirring is completed, the stirring device is turned off by the start-stop controller 1-11.

[0094] The evenly stirred phosphogypsum mixture is taken out from the double S composite full-shaft densely distributed crushing rod type stirring device and placed in a container of a certain capacity for easy loading. According to the predetermined compaction degree, the design value of the molding sample and the volume of the cylindrical molding mold 2-9, the phosphogypsum mixture is calculated and weighed, the phosphogypsum modified material density compaction-humidity determination device is turned upside down to a fixed surface, and the cylindrical molding mold 2-9 is put on the contact block 2-2 of the phosphogypsum modified material density compaction-humidity determination device as the base of the cylindrical molding mold 2-9, and the phosphogypsum mixture is loaded into the cylindrical molding mold 2-9 in layers, generally in three layers. The phosphogypsum mixture to be loaded into the cylindrical molding mold 2-9 is divided into three equal parts and loaded into the mold in turn. After each layer is filled, it is gently and evenly compacted with a tamping rod; during the loading process, the tamping rod is used manually to compact in a clockwise direction. After compaction, the contact block 2-2 is placed above the cylindrical molding mold 2-9 and placed on a press where the whole is placed. The total vertical displacement of the upper and lower contact blocks 2-2 that need to be pressed in is read through the scale line 2-3 and used as the preset displacement of the press. The phosphogypsum mixture is compacted by the pressure-bearing structure 2-1 and the contact block 2-2. When one of the upper and lower scale alarms 2-4 sounds an alarm, pay attention to the compaction process and continue compacting. When the upper and lower scale alarms 2-4 sound an alarm at the same time, it means that the contact block 2-2 has reached the preset displacement value, and compaction should be stopped at this time. The position of the water-absorbing color-changing desiccant 2-8 is observed through the wetness observation line 2-7 of the wetness test tube 2-5, indicating the amount of water squeezed out of the phosphogypsum mixture. Because the bottom of the wetness test tube (the part directly in contact with the phosphogypsum mixture) is provided with a bottom filter 2-6, which prevents the phosphogypsum mixture from being poured into the wetness test tube 2-5, the water-absorbing color-changing desiccant 2-8 at this time represents the amount of water squeezed out, so that it can be judged whether the water added to the phosphogypsum mixture is reasonable, achieving the purpose of controlling the compaction and curing quality of the phosphogypsum mixture by density compaction degree-wetness dual control. After compaction is completed, the cylindrical forming mold 2-9 together with the contact pressing block 2-2 and the pressure-bearing structure 2-1 are placed at room temperature for 6 hours, and then demolded and subjected to standard curing.

[0095] The technical solution of the present invention is adopted, that is, phosphogypsum and a modifier are mixed under the action of water, and the stirring method and device provided by the present invention are used for mixing. At the same time, the compaction is carried out by the compaction control method proposed in the present invention, and the compaction is controlled by soaking wetness, thereby achieving good results. The specific test data are shown in Table 1.

[0096] However, the conventional solution, that is, mixing phosphogypsum with cement-stabilized materials, using ordinary mixing equipment for mixing, and the compaction degree is generally controlled to the mass ratio of the maximum dry density, the effect achieved is inferior to that of the solution of the present invention.

[0097] Table 1

[0098] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A phosphogypsum modified material for highways under a new excitation system, characterized in that: The raw materials include the following in percentage by weight: 80% to 90% phosphogypsum, 10% to 20% modifier, totaling 100%; It also includes water, the mass of which is 15% to 18% of the total mass of phosphogypsum and modifier; The modifier includes the following raw materials in parts by weight: 4.8-5.2 parts of calcium oxide, 5.8-6.2 parts of silicon dioxide, 3.9-4.1 parts of aluminum oxide, 9.9-10.1 parts of iron oxide, 39-41 parts of mineral powder, 29-31 parts of tricalcium silicate, 1.9-2.1 parts of calcium carbonate, 0.9-1.1 parts of sodium silicate, 0.9-1.1 parts of coupling agent, 0.48-0.52 parts of iron powder, and 0.48-0.52 parts of rubber powder.

2. The phosphogypsum modified material for highway under the new excitation system according to claim 1, characterized in that: The coupling agent used is aluminate coupling agent; the activity index of the mineral powder is required to be no less than 75%; the iron powder is required to be no less than 500 mesh; the purity of the rubber powder is required to be no less than 99% and no less than 500 mesh.

3. The method for preparing a modified phosphogypsum material for highways under a new excitation system according to claim 1 or 2, characterized in that: The steps include: Step (1), ingredients: weigh phosphogypsum, modifier and water; Step (2), mixing: stirring the phosphogypsum, modifier and water weighed in step (1) until they are uniformly mixed to obtain a phosphogypsum modified material; wherein the stirring speed is not less than 500 r / min; Step (3), compaction test: the compaction density control index and the wetness control index of the phosphogypsum modified material are tested. If the compaction control index requirement is not less than 98% of the maximum dry density, and the wetness control index is within the range of 5 mm to 10 mm, the test is passed and the compliant material is used in the design of the highway pavement base structure. If the test fails, the batch of materials cannot be used in the design of highway pavement base structure and should be scrapped.

4. The method for preparing a modified phosphogypsum material for highways under a new excitation system according to claim 3, characterized in that: Step (2), stirring using a double S composite full-shaft densely distributed crushing rod type stirring device, the double S composite full-shaft densely distributed crushing rod type stirring device comprising a supporting base (1-13); A stirring chamber (1-8) is mounted on the supporting base (1-13); the stirring chamber (1-8) is rotatable relative to the supporting base (1-13); The top of the stirring chamber (1-8) is provided with a feed port and a discharge port (1-6); The feed and discharge ports (1-6) are provided with fixed covers (1-7); Also includes an electric motor (1-1) and a high-speed rotating machine (1-2); The power output end of the electric motor (1-1) is connected to the power output end of the high-speed rotating machine (1-2) to provide a power source for the high-speed rotating machine (1-2); The stirring chamber (1-8) is equipped with a high-speed rotating shaft (1-3); the other end of the high-speed rotating shaft (1-3) extends out of the stirring chamber (1-8) and is connected to the power output end of the high-speed rotating machine (1-2); the high-speed rotating machine (1-2) is used to drive the high-speed rotating shaft (1-3) to rotate; A double S-type stirring blade (1-4) and a full-shaft densely distributed breaking rod type stirring blade (1-5) are installed on the high-speed rotating shaft (1-3) inside the stirring chamber (1-8).

5. The method for preparing a modified phosphogypsum material for highways under a new excitation system according to claim 4, characterized in that: A stirring chamber (1-8) is mounted on the support base (1-13) via a fixture (1-14); The double S stirring blades are symmetrically welded on the high-speed rotating shaft (1-3) in the stirring chamber (1-8), and the full-shaft densely distributed breaking rod type stirring blades (1-5) are welded on the high-speed rotating shaft (1-3) around the high-speed rotating shaft (1-3).

6. The method for preparing a modified phosphogypsum material for highways under a new excitation system according to claim 4, characterized in that: It also includes a stirring time controller (1-9), a stirring speed controller (1-10), a start-stop controller (1-11) and an emergency stop button (1-12); The stirring time controller (1-9) is used to control the stirring time; The stirring speed controller (1-10) is used to control the stirring speed; The start-stop controller (1-11) is used to control the start and stop of the motor (1-1) when the motor (1-1) is powered on; The emergency stop button (1-12) is used to control the power supply of the motor (1-1) on and off.

7. The method for preparing a modified phosphogypsum material for highways under a new excitation system according to claim 3, characterized in that: In step (3), during the compaction test, the wetness control index is tested using a phosphogypsum modified material density compaction wetness measuring device; The device for measuring density and moisture content of phosphogypsum modified materials by compaction comprises a pressure-bearing structure (2-1), a contact pressure block (2-2) and a cylindrical forming mold (2-9); A contact pressure block (2-2) is installed on the top and bottom of the cylindrical forming mold (2-9), and a pressure-bearing structure (2-1) is installed on the side of the contact pressure block (2-2) away from the cylindrical forming mold (2-9); The contact pressing block (2-2) is provided with scale lines (2-3); The contact pressing block (2-2) also has a scale alarm (2-4); when the edge of the cylindrical forming mold (2-9) is flush with the scale line (2-3) at 0 cm, the scale alarm (2-4) will sound an alarm; Four immersion humidity test tubes (2-5) are centrally symmetrically arranged around the contact pressing block (2-2); the immersion humidity test tubes (2-5) penetrate the contact pressing block (2-2), one side of the immersion humidity test tubes (2-5) extends out of the contact pressing block (2-2), and the other side directly contacts the phosphogypsum modified material in the cylindrical forming mold (2-9); A filter screen (2-6) is arranged at the bottom of the humidity test tube (2-5), and a water-absorbing color-changing desiccant (2-8) is arranged inside; A humidity observation line (2-7) is provided on the humidity test tube (2-5).

8. The method for preparing a modified phosphogypsum material for highways under a new excitation system according to claim 7, characterized in that: The scale line (2-3) on one side of the contact pressure block (2-2) close to the pressure-bearing structure (2-1) is 0 cm, and the scale line (2-3) on the other side is 5 cm; The 0 cm scale of the wetness observation line (2-7) is flush with the side of the contact pressure block (2-2) close to the pressure-bearing structure (2-1), and a 1 cm scale range is set upwards.

9. The double S composite full-shaft densely distributed crushing rod type stirring device as described in any one of claims 4 to 6.

10. The device for measuring density compaction and moisture content of phosphogypsum modified materials according to any one of claims 7 to 8.

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