Phosphogypsum ceramic sand composite road base material and preparation method thereof

Abstract

The application relates to the field of road base materials, and particularly discloses a phosphogypsum and ceramic sand composite road base material and a preparation method, the phosphogypsum and ceramic sand composite road base material is prepared from the following raw materials in parts by weight: modified phosphogypsum powder 100-110 parts, ceramic sand 10-16 parts, water 18-24 parts, a retarder 0.2-0.4 parts, a waterproof agent 0.2-0.4 parts, chrysalis 0.5-1.5 parts and wollastonite 0.5-1.5 parts. The phosphogypsum and ceramic sand composite road base material provided by the application has good compression resistance, frost resistance and water resistance, the content of phosphogypsum and ceramic sand in the material is more than 90%, the comprehensive utilization of waste phosphogypsum and recycled ceramic sand is realized, resources are saved, and the application is beneficial to environmental protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of road base materials, in particular to a phosphogypsum ceramic sand composite road base material and a preparation method thereof. BACKGROUND

[0002] Phosphogypsum is a solid waste produced in the wet-process phosphoric acid process, and its components mainly include calcium sulfate dihydrate, and also include incompletely decomposed phosphate rock, residual phosphoric acid, fluorides, organic matter, etc., among which the presence of fluorides and organic matter has the greatest impact on the resource utilization of phosphogypsum. The random discharge and accumulation of phosphogypsum have seriously damaged the ecological environment, not only polluting groundwater resources, but also wasting land resources.

[0003] Regenerated ceramic particles are materials made of waste such as sludge, tailings, and construction waste, instead of traditional clay and shale, and are obtained by sintering. The fine particles in the ceramic particles are usually referred to as ceramic sand. Due to the porous structure inside, the density of the ceramic sand is small, and the thermal conductivity is low.

[0004] In order to realize the reuse of waste phosphogypsum and regenerated ceramic particles / sand, the waste phosphogypsum can be modified by harmless treatment and used as a cementing material for road base materials, and the regenerated ceramic particles or ceramic sand can be used as fine aggregate for road base materials. In order to improve the utilization rate of waste, people usually want to increase the content of waste phosphogypsum and regenerated ceramic particles / sand in road base materials. However, due to the presence of various organic matter and various harmful substances such as strong acid, soluble phosphorus, and fluorine in the phosphogypsum, it is extremely unfavorable to use it as a building material. The porosity of the regenerated ceramic particles / sand is high, and it is easy to segregate and bleed water during mixing. When the content of waste phosphogypsum and regenerated ceramic particles / sand in the road base material is high, it will result in that it cannot be used as a road base material. SUMMARY

[0005] In view of the deficiencies in the prior art, the first object of the present application is to provide a phosphogypsum ceramic sand composite road base material, which has good compression resistance, frost resistance, and water resistance, and the content of waste phosphogypsum and regenerated ceramic sand in the raw material is more than 90%, realizing the comprehensive utilization of waste phosphogypsum and regenerated ceramic sand, saving resources, and being beneficial to environmental protection. The waste phosphogypsum is modified by treatment and used as a cementing material, and the regenerated light fine aggregate ceramic sand is used as a road base material.

[0006] The second object of the present application is to provide a preparation method of a phosphogypsum ceramic sand composite road base material, which is simple and easy to implement.

[0007] To achieve the above-mentioned first object, the present application provides the following technical solutions:

[0008] The phosphogypsum ceramic sand composite road base material is prepared from the following raw materials in parts by weight: modified phosphogypsum 100-110 parts, ceramic sand 10-16 parts, water 18-24 parts, retarder 0.2-0.4 parts, waterproof agent 0.2-0.4 parts, chrysalis 0.5-1.5 parts, and wollastonite 0.5-1.5 parts.

[0009] The modified phosphogypsum is obtained by calcining and ball milling of phosphogypsum.

[0010] By using the above technical solution, the phosphogypsum is used as a raw material, and after harmless treatment and modification, it is used as a cementing material, and the regenerated ceramic sand is used as a fine aggregate, thereby realizing the comprehensive utilization of phosphogypsum and ceramic sand. By adding chrysalis and wollastonite, the calcium ions in the phosphogypsum and the calcium ions in the wollastonite can be chelated with organic matter such as chitosan in the chrysalis, so that the chrysalis, the phosphogypsum and the wollastonite are cross-linked, the mechanical properties of the phosphogypsum ceramic sand composite road base material are improved, and the material has good strength and water resistance and frost resistance. In the raw materials of the road base material, the content of waste phosphogypsum and ceramic sand is more than 90%, which meets the use requirements, and the utilization rate of waste is effectively improved.

[0011] The phosphogypsum is waste phosphogypsum, which is a solid waste produced in the wet-process phosphoric acid process, and its main component is calcium sulfate dihydrate.

[0012] Further, the chrysalis is modified chrysalis, and the preparation method of the modified chrysalis is as follows:

[0013] The chrysalis is washed with water, dried, and then crushed and sieved;

[0014] Ethanol and magnesium sulfate solution are mixed to obtain an ethanol / magnesium sulfate solution;

[0015] The crushed and sieved chrysalis and the ethanol / magnesium sulfate solution are mixed, filtered, the filter residue is washed with water, and dried to obtain the modified chrysalis.

[0016] Preferably, the ethanol is 95% ethanol, the concentration of the magnesium sulfate solution is 0.2 mol / L, the ethanol and the magnesium sulfate solution are mixed at a volume ratio of (1-3):1, and the chrysalis and the ethanol / magnesium sulfate solution are mixed at a weight ratio of (1-2):5.

[0017] By using the above technical solution, after modification, the surface properties of the chrysalis change, the activity of organic matter such as chitosan on the surface of the chrysalis is improved, which helps to enhance the chelation of calcium in the chrysalis, and further enhances the cross-linking between the chrysalis, the phosphogypsum and the wollastonite, thereby improving the performance of the phosphogypsum ceramic sand composite road base material.

[0018] Further, the ceramic sand is modified ceramic sand, which is prepared by mixing ceramic sand and sodium methyl silicate at a weight ratio of (50-70):1.

[0019] By adopting the above technical scheme, after the ceramic sand is modified by sodium methyl silicate, the surface hydrophobicity of the internal pores of the ceramic sand is enhanced, and the retention of water in the internal pores of the ceramic sand is reduced, thereby improving the water resistance and frost resistance of the phosphogypsum ceramic sand composite road base material, and being conducive to improving the strength of the phosphogypsum ceramic sand composite road base material.

[0020] Further, the retarder is selected from one or more of sodium citrate, sodium polyphosphate, potassium tartrate, sodium acrylate, and borax, and the waterproofing agent is selected from one or more of sodium methyl silicate, methyl hydrogen silicone oil, methyl silicone resin, calcium stearate, and zinc stearate.

[0021] By adopting the above technical scheme, the retarder helps to slow down the speed of water hardening of the phosphogypsum, prolong the setting time, and provide convenience for construction; and the waterproofing agent helps to improve the water resistance and frost resistance of the phosphogypsum ceramic sand composite road base material.

[0022] Further, the wollastonite is ultra-fine wollastonite, and the aspect ratio of the ultra-fine wollastonite is (10-20):1.

[0023] By adopting the above technical scheme, the needle-like ultra-fine wollastonite is dispersed and filled in the road base material, and effective support is formed in the road base material, thereby improving the mechanical properties of the phosphogypsum ceramic sand composite road base material; at the same time, the chelation of the organic matter such as chitosan in the chrysalis and the calcium in the wollastonite and the calcium in the phosphogypsum occurs simultaneously, thereby causing cross-linking between the chrysalis, the phosphogypsum, and the wollastonite, and improving the performance of the phosphogypsum ceramic sand composite road base material.

[0024] Further, preparing the phosphogypsum ceramic sand composite road base material further includes 0.2-0.4 parts by weight of sodium silicate.

[0025] Further, preparing the phosphogypsum ceramic sand composite road base material further includes 0.2-0.4 parts by weight of sodium carboxymethyl cellulose.

[0026] By adopting the above technical scheme, sodium silicate and sodium carboxymethyl cellulose synergize to play a gluing role in the phosphogypsum ceramic sand composite road base material, so that the components in the phosphogypsum ceramic sand composite road base material are more closely combined, thereby improving the performance of the phosphogypsum ceramic sand composite road base material.

[0027] To achieve the above-mentioned second object, the present application provides the following technical scheme:

[0028] A preparation method of a phosphogypsum ceramic sand composite road base material includes the following steps:

[0029] S1. calcining, ball milling the phosphogypsum to obtain modified phosphogypsum powder;

[0030] S2. mixing the modified phosphogypsum powder, ceramic sand, water, retarder and waterproof agent to obtain a phosphogypsum ceramic sand mixture;

[0031] S3. adding chrysalis, wollastonite and other raw materials to the phosphogypsum ceramic sand mixture obtained in step S2, and mixing to obtain a phosphogypsum ceramic sand composite road base material.

[0032] Further, the step S2 comprises the following steps:

[0033] S2-1. mixing the modified phosphogypsum powder, the retarder and 35%-45% of the total amount of water to obtain a first homogeneous mixture;

[0034] S2-2. adding ceramic sand, waterproof agent and the remaining water to the first homogeneous mixture obtained in step S2-1, and mixing to obtain a phosphogypsum ceramic sand mixture.

[0035] Preferably, in the step S1, the temperature of the calcination is controlled to be 200-400℃, preferably 300℃.

[0036] Preferably, the average particle size of the modified phosphogypsum powder is 80-120μm.

[0037] By the above technical solution, the utilization of waste phosphogypsum is realized. The waste phosphogypsum is a waste and belongs to garbage, which cannot be directly applied to engineering construction. Through the modification treatment such as calcination and ball milling, the strong acid, organic matter, soluble phosphorus and fluorine content of the waste phosphogypsum can be removed, and the modified phosphogypsum powder can be obtained. The modified phosphogypsum powder can replace natural gypsum and be used as inorganic binder.

[0038] Further, the step S3 comprises the following steps:

[0039] S3-1. adding wollastonite to the phosphogypsum ceramic sand mixture obtained in step S2, mixing, then adding chrysalis, and mixing; S3-2. adding other raw materials to the product obtained in step S3-1 to obtain a phosphogypsum ceramic sand composite road base material.

[0040] By adopting the above technical solution, in the process of mixing the phosphogypsum with water, the water is more easily dispersed uniformly in the phosphogypsum when the water is added twice, so that the compatibility of various raw materials is better; in the process of mixing the phosphogypsum ceramic sand mixture with chrysalis and wollastonite, the phosphogypsum ceramic sand mixture is first mixed with wollastonite to uniformly disperse the calcium element, and then the chrysalis is added, so that the chelation effect of the chrysalis on calcium is better, thereby improving the performance of the phosphogypsum ceramic sand composite road base material.

[0041] In summary, the present application includes the following beneficial technical effects:

[0042] 1. The present application provides a phosphogypsum ceramic sand composite road base material, using phosphogypsum as binder and recycled ceramic sand as fine aggregate, realizing the comprehensive utilization of phosphogypsum and ceramic sand, and the content of phosphogypsum and ceramic sand in the phosphogypsum ceramic sand composite road base material is more than 90%, effectively improving the waste utilization rate.

[0043] 2. By adding chrysalis and wollastonite, the mechanical properties of the phosphogypsum ceramic sand composite road base material are improved, so that it has good strength and water resistance and frost resistance, meeting the use requirements of road base material, the 7-day unconfined compressive strength is more than 5MPa, the compressive strength loss after 5 freeze-thaw cycles is less than 1%, the scouring mass loss is less than 1%, and the softening coefficient is more than 0.85, and at the same time, it has a long setting time, meeting the construction requirements.

[0044] 3. The present application provides a preparation method of the phosphogypsum ceramic sand composite road base material, which is simple and easy to implement, uses a secondary homogenization method to fully mix the phosphogypsum and water, and adjusts the addition order of each component to improve the mixing effect between each component, thereby improving the performance of the phosphogypsum ceramic sand composite road base material. DETAILED DESCRIPTION

[0045] The present application is further described in detail below in conjunction with examples. The following examples are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. If the specific conditions are not specified in the following examples, the conventional conditions or the conditions recommended by the manufacturer are used, and the methods used are the conventional methods known in the art unless otherwise specified. In addition, any method or material similar or equivalent to that described can also be applied in the present application. The ceramic sand is recycled ceramic sand lightweight aggregate produced by Hubei Juhai Environmental Technology Co., Ltd., with a particle size of less than 5mm and a density of 700-800Kg / m 3 .

[0046] Examples 1-3

[0047] Examples 1-3 respectively provide a phosphogypsum ceramic sand composite road base material.

[0048] The difference between Examples 1-3 is that the weight parts of the raw materials for preparing the phosphogypsum ceramic sand composite road base material are different, as shown in Table 1.

[0049] The preparation method of the phosphogypsum ceramic sand composite road base material is as follows:

[0050] 1) waste phosphogypsum (phosphogypsum) is calcined (free water, crystal water is removed) at high temperature (300℃), ball milled to obtain modified phosphogypsum powder, the average particle size of the modified phosphogypsum powder is 100.8μm;

[0051] 2) the modified phosphogypsum powder obtained in step 1) is mixed with a retarder, 40% of the total amount of water to obtain a first homogeneous mixture;

[0052] 3) adding ceramic sand, waterproofing agent and 60% of the total amount of water to the first homogeneous mixture obtained in step 2), mixing to obtain a phosphogypsum ceramic sand mixture;

[0053] 4) adding wollastonite to the phosphogypsum ceramic sand mixture obtained in step 3), mixing, then adding crushed chrysalis, mixing to obtain a phosphogypsum ceramic sand composite road base material.

[0054] Among them, the retarder is sodium citrate, the waterproofing agent is sodium methyl silicate, the wollastonite is wollastonite powder, and the aspect ratio of the wollastonite is 15:1.

[0055] Table 1 provides the weight parts of the raw materials for preparing the phosphogypsum ceramic sand composite road base material in examples 1-3

[0056]

[0057] Example 4

[0058] Example 4 provides a phosphogypsum ceramic sand composite road base material, the raw materials and preparation method refer to example 2, the difference between example 4 and example 2 is that in step 2), the retarder is replaced by sodium polyphosphate, and in step 3), the waterproofing agent is replaced by sodium stearate.

[0059] Examples 5-6

[0060] Examples 5-6 respectively provide a phosphogypsum ceramic sand composite road base material, the raw materials and preparation method refer to example 2, the difference between examples 5-6 and example 2 is that the weight parts of chrysalis in the phosphogypsum ceramic sand composite road base material are different, as shown in Table 2.

[0061] Table 2 provides the weight parts of the raw materials for preparing the phosphogypsum ceramic sand composite road base material in examples 5-6

[0062]

[0063] Example 7

[0064] Example 7 provides a phosphogypsum ceramic sand composite road base material, raw materials refer to example 2, the preparation method is as follows: 1) the waste phosphogypsum is calcined (remove free water, crystal water) at high temperature (300℃), ball milled, and modified phosphogypsum powder is obtained, the average particle size of the modified phosphogypsum powder is 100.8μm; 2) the modified phosphogypsum powder obtained in step 1) is mixed with retarder, ceramic sand, waterproof agent and water to obtain a phosphogypsum ceramic sand mixture;

[0065] 3) adding wollastonite to the phosphogypsum ceramic sand mixture obtained in step 2), mixing, then adding crushed chrysalis, mixing, to obtain a phosphogypsum ceramic sand composite road base material.

[0066] Example 8

[0067] Example 8 provides a phosphogypsum ceramic sand composite road base material, raw materials refer to example 2, the preparation method is as follows: 1) the waste phosphogypsum is calcined (remove free water, crystal water) at high temperature (300℃), ball milled, and modified phosphogypsum powder is obtained, the average particle size of the modified phosphogypsum powder is 100.8μm;

[0068] 2) the modified phosphogypsum powder obtained in step 1) is mixed with retarder, 40% of the total amount of water to obtain a first homogeneous mixture;

[0069] 3) adding ceramic sand, waterproof agent and 60% of the total amount of water to the first homogeneous mixture obtained in step 2), mixing, to obtain a phosphogypsum ceramic sand mixture;

[0070] 4) adding crushed chrysalis to the phosphogypsum ceramic sand mixture obtained in step 3), mixing, then adding wollastonite, mixing, to obtain a phosphogypsum ceramic sand composite road base material.

[0071] Example 9

[0072] Example 9 provides a phosphogypsum ceramic sand composite road base material, raw materials and preparation method refer to example 2, the difference between example 9 and example 2 is that in step 4), the chrysalis is replaced by modified chrysalis, and the preparation method of the modified chrysalis is as follows:

[0073] 1) washing the chrysalis with water, drying and crushing;

[0074] 2) mixing 95% ethanol and 0.2mol / L magnesium sulfate solution according to the volume ratio of 2:1 to obtain an ethanol / magnesium sulfate solution;

[0075] 3) mixing the dry chrysalis obtained in step 1) and the ethanol / magnesium sulfate solution obtained in step 2) according to the weight ratio of 1.5:5, heating and stirring at 50-60℃ for 3h to obtain a modified chrysalis mixture;

[0076] 4) The modified chrysalis mixture obtained in step 3) is filtered, the residue is washed with water and dried to obtain modified chrysalis.

[0077] Example 10

[0078] Example 10 provides a phosphogypsum and ceramic sand composite road base material. The raw materials and the preparation method are referred to Example 9. The difference between Example 10 and Example 9 is that in step 4), the ceramic sand is replaced by modified ceramic sand, and the preparation method of the modified ceramic sand is as follows: ceramic sand and sodium methyl silicate are mixed at a weight ratio of 60:1, and stirred at room temperature for 2h.

[0079] Example 11

[0080] Example 11 provides a phosphogypsum and ceramic sand composite road base material. The raw materials and the preparation method are referred to Example 10. The difference between Example 11 and Example 10 is that in step 4), the aspect ratio of the wollastonite is 10:1.

[0081] Example 12

[0082] Example 12 provides a phosphogypsum and ceramic sand composite road base material. The raw materials and the preparation method are referred to Example 10. The difference between Example 12 and Example 10 is that in step 4), the aspect ratio of the wollastonite is 20:1.

[0083] Example 13

[0084] Example 13 provides a phosphogypsum and ceramic sand composite road base material. The raw materials and the preparation method are referred to Example 10. The difference between Example 13 and Example 10 is that the raw materials for preparing the phosphogypsum and ceramic sand composite road base material further include sodium silicate, and step 4) is as follows: wollastonite is added to the phosphogypsum and ceramic sand mixture obtained in step 3), mixed uniformly, then chrysalis is added, mixed uniformly, and then 0.3 parts by weight of sodium silicate is added, mixed uniformly to obtain the phosphogypsum and ceramic sand composite road base material.

[0085] Example 14

[0086] Example 14 provides a phosphogypsum and ceramic sand composite road base material. The raw materials and the preparation method are referred to Example 10. The difference between Example 14 and Example 10 is that the raw materials for preparing the phosphogypsum and ceramic sand composite road base material further include sodium carboxymethyl cellulose, and step 4) is as follows: wollastonite is added to the phosphogypsum and ceramic sand mixture obtained in step 3), mixed uniformly, then chrysalis is added, mixed uniformly, and then 0.3 parts by weight of sodium carboxymethyl cellulose is added, mixed uniformly to obtain the phosphogypsum and ceramic sand composite road base material.

[0087] Example 15

[0088] Example 15 provides a phosphogypsum ceramic sand composite road base material, the preparation method refers to Example 10, and the difference between Example 15 and Example 10 is that the raw materials for preparing the phosphogypsum ceramic sand composite road base material further include sodium silicate and sodium carboxymethyl cellulose, and step 4) is: adding wollastonite to the phosphogypsum ceramic sand mixture obtained in step 3), mixing uniformly, then adding chrysalis, mixing uniformly, then adding 0.3 parts by weight of sodium silicate and 0.3 parts by weight of sodium carboxymethyl cellulose, mixing uniformly to obtain the phosphogypsum ceramic sand composite road base material.

[0089] Comparative Example 1

[0090] Comparative Example 1 provides a phosphogypsum ceramic sand composite road base material, the raw materials and preparation method refer to Example 2, and the difference between Comparative Example 1 and Example 2 is that no chrysalis is added in step 4).

[0091] Comparative Example 2

[0092] Comparative Example 2 provides a phosphogypsum ceramic sand composite road base material, the raw materials and preparation method refer to Example 2, and the difference between Comparative Example 2 and Example 2 is that no wollastonite is added in step 4).

[0093] Comparative Example 3

[0094] Comparative Example 3 provides a phosphogypsum ceramic sand composite road base material, the raw materials and preparation method refer to Example 2, and the difference between Comparative Example 3 and Example 2 is that the ceramic sand is replaced by natural sand in step 3).

[0095] Comparative Example 4

[0096] Comparative Example 4 provides a phosphogypsum ceramic sand composite road base material, the raw materials refer to Example 2, and the preparation method is as follows: 1) calcining, ball milling and obtaining modified phosphogypsum powder by high temperature (300°C) calcining of waste phosphogypsum, the average particle size of the modified phosphogypsum powder is 100.8 μm;

[0097] 2) mixing the modified phosphogypsum powder obtained in step 1) with a retarder, ceramic sand, a waterproof agent, water, wollastonite and crushed chrysalis to obtain a phosphogypsum ceramic sand composite road base material.

[0098] Performance detection

[0099] The phosphogypsum road base material provided in Examples 1-15 and Comparative Examples 1-4 of the present application is subjected to the following performance detection according to the test method in JTG E51-2009 "Highway Engineering Inorganic Binder Stabilized Material Test Procedures".

[0100] Unconfined compressive strength: detected according to T 0805-1994 "Unconfined compressive strength test method of inorganic binder stabilized material"; loss of compressive strength after freeze-thaw: detected according to T 0858-2009 "Freeze-thaw test method of inorganic binder stabilized material";

[0101] Loss of mass under scouring: detected according to T 0860-2009 "Scouring test method of inorganic binder stabilized material".

[0102] The phosphogypsum road base material provided by the embodiments 1-15 and the comparative examples 1-4 of the present application was detected for the softening coefficient according to the test method in JC / T698-2010 "Gypsum block".

[0103] The phosphogypsum road base material provided by the embodiments 1-15 and the comparative examples 1-4 of the present application was detected for the setting time according to GB / T1346-2011 "Cement standard consistency water consumption, setting time and stability test method".

[0104] The detection data are shown in Tables 3 and 4.

[0105] Table 3: detection result data table of 7-day unconfined compressive strength, compressive strength after 5 freeze-thaw cycles, loss of compressive strength after 5 freeze-thaw cycles, loss of mass under scouring, and softening coefficient of the embodiments 1-15 and the comparative examples 1-4

[0106]

[0107]

[0108] Table 4: detection result data table of initial setting time, final setting time, and setting time of the embodiments 1-15 and the comparative examples 1-4

[0109] Test item Initial setting time (min) Final setting time (min) Setting time (min) Example 1 204 284 80 Example 2 216 303 87 Example 3 209 292 83 Example 4 200 285 85 Example 5 213 294 81 Example 6 211 292 81 Example 7 185 255 70 Example 8 188 259 71 Example 9 248 345 97 Example 10 264 374 110 Example 11 261 365 104 Example 12 257 362 105 Example 13 273 386 113 Example 14 275 386 111 Example 15 294 415 121 Comparative Example 1 170 237 67 Comparative Example 2 172 240 68 Comparative Example 3 193 267 74 Comparative Example 4 166 222 56

[0110] The present application is described in detail in combination with the detection data provided in Tables 3 and 4 as follows.

[0111] The embodiments 1-3 investigated the influence of the content of each component in the phosphogypsum and ceramic sand composite road base material on the performance of the phosphogypsum and ceramic sand composite road base material, and the results showed that changing the addition amount of phosphogypsum, ceramic sand, water, retarder and waterproof agent had slight influence on the performance of the phosphogypsum and ceramic sand composite road base material, but all could meet the use requirements, and the embodiment 2 was relatively better.

[0112] Compared with Example 2, Example 4 changes the types of the retarder and the water-proof agent, and the results show that when the retarder is replaced by sodium polyphosphate and the water-proof agent is replaced by sodium stearate, the performance of the phosphogypsum-sand composite road base material is slightly affected, but still meets the use requirements, and Example 2 is relatively optimal.

[0113] Compared with Example 2, Examples 5-6 investigate the influence of the chrysalis addition amount on the performance of the phosphogypsum-sand composite road base material, and the results show that changing the chrysalis addition amount has a slight influence on the performance of the phosphogypsum-sand composite road base material, but all can meet the use requirements, and Example 2 is relatively optimal.

[0114] Compared with Example 2, Example 7 changes the mixing mode of the phosphogypsum, sand, water, retarder and water-proof agent, and the performance of the phosphogypsum-sand composite road base material of Example 2 is better than that of Example 7. When the water is added twice, the water is more evenly dispersed in the phosphogypsum, so that the compatibility of various raw materials is better, which helps to improve the performance of the road base material.

[0115] Compared with Example 2, Example 8 changes the mixing mode of the phosphogypsum-sand mixture and the chrysalis and wollastonite, and the results show that when the wollastonite is added first and then the chrysalis is added, the performance of the phosphogypsum-sand composite road base material is better. This may be because the phosphogypsum-sand mixture is mixed with the wollastonite first, so that the calcium element is uniformly dispersed, and then the chrysalis is added, so that the chelation effect of the chrysalis on calcium is better, thereby improving the performance of the phosphogypsum-sand composite road base material.

[0116] Compared with Example 2, Example 9 replaces the chrysalis with modified chrysalis, and the results show that the modified chrysalis has a better improvement effect on the performance of the phosphogypsum-sand composite road base material. This may be because after modification, the surface properties of the chrysalis change, the activity of the organic matter such as chitosan on the surface of the chrysalis is improved, which helps to enhance the chelation of the organic matter such as chitosan in the chrysalis to calcium, thereby enhancing the cross-linking between the chrysalis and the phosphogypsum and the wollastonite, and improving the performance of the phosphogypsum-sand composite road base material.

[0117] Compared with Example 9, Example 10 replaces the sand with modified sand, and the results show that the modified sand has a better improvement effect on the performance of the phosphogypsum-sand composite road base material. This may be because after the sand is modified by sodium methyl silicate, the hydrophobicity of the surface of the internal pores of the sand is enhanced, which reduces the retention of water in the internal pores of the sand, thereby improving the water resistance and frost resistance of the phosphogypsum-sand composite road base material, and at the same time, the bleeding phenomenon during mixing is also reduced, which is conducive to improving the strength of the phosphogypsum-sand composite road base material.

[0118] Compared with Example 10, Examples 11-12 investigate the influence of the aspect ratio of wollastonite on the performance of the phosphogypsum-ceramic sand composite road base material, and the results show that the moderate aspect ratio helps to improve the compatibility of wollastonite with other components, effectively disperses and fills wollastonite in the road base material, and forms effective support in the road base material, thereby improving the performance of the phosphogypsum-ceramic sand composite road base material.

[0119] Based on Example 10, Examples 13-15 add one or both of sodium silicate and sodium carboxymethyl cellulose, and the results show that sodium silicate and sodium carboxymethyl cellulose synergize to further improve the microstructure of the phosphogypsum-ceramic sand composite road base material, resulting in increased strength, improved water resistance and frost resistance, and prolonged setting time.

[0120] Compared with Example 2, the performance of the phosphogypsum-ceramic sand composite road base material of Comparative Examples 1-2 is significantly deteriorated, indicating that the addition of chrysalis and wollastonite helps to improve the performance of the phosphogypsum-ceramic sand composite road base material.

[0121] Compared with Example 2, the performance of the phosphogypsum-ceramic sand composite road base material of Comparative Example 3 is significantly deteriorated, and the compatibility of ceramic sand and phosphogypsum is better than that of natural sand, so using recycled ceramic sand as fine aggregate not only saves natural sand resources, but also realizes the comprehensive utilization of ceramic sand.

[0122] Compared with Example 2, the performance of the phosphogypsum-ceramic sand composite road base material of Comparative Example 4 is significantly deteriorated, indicating that when the raw materials are mixed at the same time, the mixing effect between the raw materials is not good, and it is difficult to realize the effect of mutual cooperation between different components.

[0123] The specific embodiments are merely an explanation of the present application, and are not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A phosphogypsum-ceramic sand composite road base material, characterized by: The phosphogypsum ceramic sand composite road base material is prepared from the following raw materials in parts by weight: modified phosphogypsum powder 100-110 parts, ceramic sand 10-16 parts, water 18-24 parts, retarder 0.2-0.4 parts, waterproof agent 0.2-0.4 parts, chrysalis 0.5-1.5 parts, and wollastonite 0.5-1.5 parts; The modified phosphogypsum powder is obtained by calcining and ball milling of phosphogypsum; The chrysalis is a pulverized chrysalis.

2. The phosphogypsum-ceramic sand composite road base material according to claim 1, characterized in that: The chrysalis is a modified chrysalis, and the preparation method of the modified chrysalis is as follows: The chrysalis is washed with water, dried, and then pulverized and sieved; Ethanol and a magnesium sulfate solution are mixed to obtain an ethanol / magnesium sulfate solution; The pulverized and sieved chrysalis and the ethanol / magnesium sulfate solution are mixed, filtered, and the filter residue is washed with water and dried to obtain the modified chrysalis.

3. The phosphogypsum-ceramic sand composite road base material according to claim 1, characterized in that: The ceramic sand is a modified ceramic sand, which is prepared by mixing ceramic sand and sodium methyl silicate at a weight ratio of (50-70):

1.

4. The phosphogypsum-ceramic sand composite road base material according to claim 1, characterized in that: The retarder is selected from one or more of sodium citrate, sodium polyphosphate, potassium tartrate, sodium acrylate, and borax, and the waterproof agent is selected from one or more of sodium methyl silicate, methyl hydrogen silicone oil, methyl silicone resin, calcium stearate, and zinc stearate.

5. The phosphogypsum-ceramic sand composite road base material according to claim 1, characterized in that: The aspect ratio of the wollastonite is (10-20):

1.

6. The phosphogypsum-ceramic sand composite road base material according to claim 1, characterized in that: Preparation of the phosphogypsum ceramic sand composite road base material further includes 0.2-0.4 parts by weight of sodium silicate.

7. The phosphogypsum-ceramic sand composite road base material according to claim 1, characterized in that: Preparation of the phosphogypsum ceramic sand composite road base material further includes 0.2-0.4 parts by weight of sodium carboxymethyl cellulose.

8. A process for the preparation of the phosphogypsum-ceramic sand composite road base material as claimed in any one of claims 1 to 7, characterized in that: The method comprises the following steps: S1. Calcining and ball milling of phosphogypsum to obtain modified phosphogypsum powder; S2. Mixing the modified phosphogypsum powder, ceramic sand, water, retarder, and waterproof agent to obtain a phosphogypsum ceramic sand mixture; S3. Adding chrysalis, wollastonite, and other raw materials to the phosphogypsum ceramic sand mixture obtained in step S2, and mixing uniformly to obtain a phosphogypsum ceramic sand composite road base material.

9. The preparation method of the phosphogypsum-ceramic sand composite road base material according to claim 8, characterized in that: The step S2 comprises the following steps: S2-1. Mixing the modified phosphogypsum powder, retarder, and 35%-45% of the total amount of water to obtain a first homogeneous mixture; S2-2. Adding ceramic sand, waterproof agent, and the remaining water to the first homogeneous mixture obtained in step S2-1, and mixing uniformly to obtain a phosphogypsum ceramic sand mixture.

10. The method of claim 8, wherein the phosphogypsum-sand composite road base material is prepared by the steps of: The step S3 comprises the following steps: ​ S3-1. Adding wollastonite to the phosphogypsum ceramic sand mixture obtained in step S2, mixing uniformly, and then adding chrysalis, and mixing uniformly; S3-2. Adding other raw materials to the product obtained in step S3-1 to obtain a phosphogypsum ceramic sand composite road base material.

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