A method for constructing a drainage ditch using floatation phosphorus tailings

Abstract

This invention discloses a method for constructing drainage ditches using flotation phosphate tailings, relating to the field of flotation phosphate tailings resource utilization technology. The method involves mixing filtered flotation phosphate tailings, gel material, coarse aggregate, water-reducing agent, polypropylene fiber, and water to prepare a slurry, which is then poured and plastered to construct the drainage ditch. More than half of the raw materials are flotation phosphate tailings, fully consuming them, achieving solid waste reuse, and replacing fine sand, thus solving the problem of fine sand shortage. The gel material is prepared by compounding mineral powder, clinker, calcium oxide, calcium chloride, anhydrous sodium sulfate, calcium sulfate dihydrate, and sodium silicate, replacing ordinary cement to achieve rapid consolidation of ultrafine flotation phosphate tailings, improving their compressive strength, and at a lower cost.

Description

Technical Field

[0001] This invention relates to the field of flotation phosphorus tailings resource utilization technology, specifically to a method for constructing drainage ditches using flotation phosphorus tailings. Background Technology

[0002] Drainage ditch construction typically uses fine sand, stones, and cement as raw materials. After slurry preparation, it is constructed through pouring and finishing processes. The fine sand used in this process is not only an indispensable building material, but also used in construction, road building, filtration, aquaculture, landscaping, as a quick-setting agent in smelting, and is a major material in glass manufacturing. Sand has a wide range of uses and has become one of the world's most scarce resources. Sand mining not only damages the environment but also poses safety risks, exacerbating the scarcity of sand resources and causing sand prices to rise steadily, leading to a year-on-year increase in the cost of drainage ditch construction.

[0003] Phosphate mining and the production of phosphate concentrate generate a large amount of tailings. These tailings mainly come from the tailings left after concentrate extraction and are classified as mining solid waste within industrial solid waste. Currently, the comprehensive utilization rate of phosphate mine tailings in my country is only about 7%, and a large amount of tailings can only be piled up in tailings ponds for a long time. Some township mines and concentrators in remote areas even directly discharge tailings into natural sites. Even tailings discharged into tailings areas have a serious impact on the surrounding environment. This is mainly manifested in the following ways: when tailings are corroded, and when certain migratable elements entering the tailings undergo chemical migration, they will cause serious pollution to the atmosphere and soil, leading to land degradation, vegetation destruction, and even directly threatening the survival of humans and livestock; dust generated on the surface of tailings ponds can worsen the sanitary conditions of the surrounding areas; and certain components in the tailings and residual beneficiation agents also cause serious harm to the ecological environment.

[0004] If this type of flotation phosphorus tailings can replace raw materials such as fine sand and cement in the construction of drainage ditches, the consumption of fine sand will be greatly reduced, and the solid waste flotation phosphorus tailings will be fully utilized, thus greatly reducing the construction cost of drainage ditches. Summary of the Invention

[0005] The purpose of this invention is to provide a method for constructing drainage ditches using flotation phosphorus tailings, thereby solving the problem of high costs caused by the scarcity of fine sand resources in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a method for constructing drainage ditches using flotation phosphate tailings, characterized in that: the flotation phosphate tailings after pressure filtration, gel material, coarse aggregate, water reducing agent, polypropylene fiber and water are mixed to prepare a slurry, and the drainage ditch is constructed by pouring and smoothing.

[0007] A further technical solution is that the water content of the flotation phosphate tailings after pressure filtration is ≤18%, the fineness is -0.038mm particle size accounts for 70% to 76%, the P2O5 content is 6% to 9%, the F content is 0.3% to 0.6%, and the pH is 5.5 to 6.6.

[0008] A further technical solution is that the gel material is a compound made by mixing mineral powder, clinker, calcium oxide, calcium chloride, anhydrous sodium sulfate, calcium sulfate dihydrate, and sodium silicate evenly.

[0009] A further technical solution is that the raw materials in the gel material, by weight, are: 70-80 parts mineral powder, 10-15 parts clinker, 2-4 parts calcium oxide, 2-4 parts calcium chloride, 1-2 parts anhydrous sodium sulfate, 1-2 parts calcium sulfate dihydrate, and 1-2 parts sodium silicate.

[0010] A further technical solution is that the mineral powder is metallurgical slag powder with a density ≥ 2.8 g / cm³. 3 Specific surface area ≥ 400 m² 2 / kg, activity index ≥95% after 28 days.

[0011] A further technical solution is that the flotation phosphorus tailings, gel material, coarse aggregate, water-reducing agent, polypropylene fiber, and water are in the following weight parts: 50-60 parts flotation phosphorus tailings, 10-15 parts coarse aggregate, 20-25 parts gel material, 1-2 parts water-reducing agent, 0.2-0.5 parts polypropylene fiber, and 10-13 parts water.

[0012] A further technical solution is to allow the drainage ditch to be cured for 28 days after construction.

[0013] Working mechanism: Using mineral powder as raw material, sodium silicate, calcium oxide and clinker as activators, and combined with anhydrous sodium sulfate, calcium sulfate dihydrate and calcium chloride to improve viscosity, a gel material that can effectively solidify ultrafine flotation phosphate tailings is obtained. When used, it can be mixed with flotation phosphate tailings, coarse aggregate, water reducing agent and polypropylene fiber to form a slurry for the construction of drainage ditches. It has good impermeability, low shrinkage rate and is environmentally friendly.

[0014] Compared with the prior art, the beneficial effects of the present invention are: it provides a simple method for constructing drainage ditches using flotation phosphate tailings, with more than half of the raw materials being flotation phosphate tailings, fully consuming the phosphate tailings, realizing solid waste reuse, and replacing fine sand, thus solving the problem of fine sand shortage; it uses mineral powder, clinker, calcium oxide, calcium chloride, anhydrous sodium sulfate, calcium sulfate dihydrate, and sodium silicate to formulate a gel material, which replaces ordinary cement, realizing rapid consolidation of ultrafine flotation phosphate tailings, improving its compressive strength, and at a lower cost. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0016] Example 1

[0017] A method for constructing drainage ditches using flotation phosphate tailings includes the following steps:

[0018] 1. Mix 75 parts S95 grade mineral powder, 15 parts clinker, 3 parts calcium oxide, 3 parts calcium chloride, 1 part anhydrous sodium sulfate, 1 part calcium sulfate dihydrate, and 2 parts sodium silicate evenly to prepare a cementitious material; the mineral powder is metallurgical slag powder with a density ≥2.8 g / cm³. 3 Specific surface area ≥ 400 m² 2 / kg, activity index ≥95% after 28 days.

[0019] 2. Mix 50 parts of flotation phosphate tailings, 15 parts of coarse aggregate, 20 parts of cementitious material, 1.5 parts of water-reducing agent, 0.5 parts of polypropylene fiber, and 13 parts of water evenly to prepare a slurry. After pressure filtration, the flotation phosphate tailings have a moisture content of 18%, a particle size of -0.038mm (70%–76%), a P2O5 content of 6%–9%, ​​a F content of 0.3%–0.6%, and a pH of 5.5–6.6.

[0020] 3. After excavating the ditch according to the design, first pour the bottom of the ditch. After curing for 3 days, the ditch wall can be supported by formwork. After the formwork is supported, pour the slurry into the formwork, compact it with a vibrator, and then cover it with geomembrane for curing. After 3 days, remove the formwork and continue curing. After 28 days, the compressive strength is 22.5MPa. After backfilling and compacting the soil around the ditch, the ditch can be put into use.

[0021] Example 2

[0022] A method for constructing drainage ditches using flotation phosphate tailings includes the following steps:

[0023] 1. Mix 80 parts of S95 grade mineral powder, 10 parts of clinker, 2 parts of calcium oxide, 2 parts of calcium chloride, 2 parts of anhydrous sodium sulfate, 2 parts of calcium sulfate dihydrate, and 2 parts of sodium silicate evenly to make a cementitious material.

[0024] 2. Mix 55 parts of flotation phosphorus tailings, 10 parts of coarse aggregate, 20 parts of cementitious material, 1.5 parts of water-reducing agent, 0.5 parts of polypropylene fiber, and 13 parts of water evenly to make a slurry.

[0025] 3. First, repair the formed ditch, then apply the prepared slurry to the surface of the formed ditch with a thickness of 15cm-30cm. After vibration to compact it, cover it with geomembrane for curing. After 28 days, the compressive strength is 20.4MPa, and it can be put into use.

[0026] Example 3

[0027] A method for constructing drainage ditches using flotation phosphate tailings includes the following steps:

[0028] 1. Mix 75 parts of S95 grade mineral powder, 11 parts of clinker, 4 parts of calcium oxide, 4 parts of calcium chloride, 2 parts of anhydrous sodium sulfate, 2 parts of calcium sulfate dihydrate, and 2 parts of sodium silicate evenly to make a cementitious material.

[0029] 2. Mix 55 parts of flotation phosphorus tailings, 10 parts of coarse aggregate, 23 parts of cementitious material, 1.8 parts of water-reducing agent, 0.2 parts of polypropylene fiber, and 10 parts of water evenly to make a slurry.

[0030] 3. The prepared slurry is injected into the U-shaped precast mold. After curing with water for 7 days, the mold is removed. After curing with water for another 28 days, the compressive strength is 22MPa. It can then be transported to the construction site for assembly. The joints are filled with cement mortar, and the edges are backfilled with soil and compacted before it can be put into use.

[0031] Example 4

[0032] To further verify the effect of the dosage of each component on the strength of the slurry used to construct drainage ditches, the data in Table 1 were obtained. As can be seen from Table 1, the optimal dosage of phosphorus tailings is 50-55 parts. Excessive use will lead to a decrease in strength, while insufficient dosage of coarse aggregate will also lead to a decrease in strength.

[0033] Table 1

[0034]

[0035]

[0036] To verify that gel materials are more effective than ordinary cement in improving the consolidation performance of flotation phosphate tailings, ordinary cement was used to replace gel materials, and the data in Table 2 were obtained. As shown in Table 2, gel materials are more effective than ordinary cement.

[0037] Table 2

[0038]

[0039] Although the invention has been described herein with reference to several illustrative embodiments, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein. More specifically, various modifications and improvements can be made to the components or layout of the subject matter combination within the scope of the disclosure and claims of this application. Besides modifications and improvements to the components or layout, other uses will be apparent to those skilled in the art.

Claims

1. A method for constructing drainage ditches using flotation phosphate tailings, characterized in that: The flotation tailings from the filter press, gel material, coarse aggregate, water-reducing agent, polypropylene fiber, and water are mixed to prepare a slurry, which is then poured and smoothed to construct drainage ditches. The gel material is a compound made by uniformly mixing mineral powder, clinker, calcium oxide, calcium chloride, anhydrous sodium sulfate, calcium sulfate dihydrate, and sodium silicate. The raw materials in the gel material, by weight, are: 70-80 parts mineral powder, 10-15 parts clinker, 2-4 parts calcium oxide, 2-4 parts calcium chloride, 1-2 parts anhydrous sodium sulfate, 1-2 parts calcium sulfate dihydrate, and 1-2 parts sodium silicate. The mineral powder is metallurgical slag powder with a density ≥2.8 g / cm³. 3 Specific surface area ≥ 400 m² 2 / kg, activity index ≥95% after 28 days; the flotation phosphorus tailings, gel material, coarse aggregate, water reducing agent, polypropylene fiber, and water are in the following weight parts: flotation phosphorus tailings 50-60 parts, coarse aggregate 10-15 parts, gel material 20-25 parts, water reducing agent 1-2 parts, polypropylene fiber 0.2-0.5 parts, and water 10-13 parts.

2. The method for constructing drainage ditches using flotation phosphate tailings according to claim 1, characterized in that: The filtered flotation phosphate tailings have a moisture content of ≤18%, a fineness of -0.038mm particles accounting for 70% to 76%, a P2O5 content of 6% to 9%, an F content of 0.3% to 0.6%, and a pH of 5.5 to 6.

6.

3. The method for constructing drainage ditches using flotation phosphate tailings according to claim 1, characterized in that: The drainage ditch was maintained for 28 days after construction.

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