High-solid-content magnesium emulsion reagent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a high-solid-content magnesium emulsion reagent as well as a preparation method and application of the high-solid-content magnesium emulsion reagent. 60 to 80 parts of water; 0.2 to 0.3 part of a thickening agent; 0.06 to 0.12 part of a stabilizing agent; 0.3 to 1 part of a surfactant; and 0.3 to 0.8 part of a dispersant. The magnesium emulsion reagent is high in solid content, stable in performance, capable of still keeping a uniform state after standing for six months, free of layering and gel, excellent in fluidity and convenient to directly use. When the wastewater treatment agent is applied to treatment of acid wastewater and heavy metal wastewater, the pH value of effluent generally does not exceed 9, and the problem of secondary pollution caused by excessive alkalization is effectively avoided; meanwhile, the reagent is high in activity and adsorption capacity, the reaction efficiency of wastewater treatment can be remarkably improved, the treatment time is shortened, the treatment cost is reduced, and remarkable economic and environmental benefits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and specifically relates to a high-solid content magnesium milk reagent, a preparation method and use thereof. Background Art

[0002] With the increasing awareness of global environmental protection, environmental protection has become a global action program. This trend has a profound impact on all walks of life, prompting them to constantly review and optimize production processes to reduce the burden on the environment. The sewage treatment industry is also facing this transformation demand. Although traditional water treatment agents such as lime, caustic soda, and soda ash have been widely used, the risks of secondary pollution, limited treatment efficiency, and strong corrosion to equipment have gradually limited their scope of application.

[0003] In this context, magnesium hydroxide has emerged as an emerging and environmentally friendly sewage treatment material, and its unique advantages have attracted much attention. For example: CN103641141A discloses a method for preparing a slurry of magnesium hydroxide with high solid content and low viscosity. The slurry has the advantages of high solid content, good fluidity, no sedimentation, and is easy to pump and store. It can be effectively used in the fields of acid wastewater treatment and flue gas desulfurization. CN116692912A discloses a method for preparing hexagonal flaky magnesium hydroxide. As an environmentally friendly inorganic material, the flaky magnesium hydroxide is widely used in antibacterial agents, acid wastewater neutralizers, fillers in the papermaking industry, precursors of magnesium oxide, neutralizers in the pharmaceutical industry, fertilizer additives, new flame retardants and other fields.

[0004] As a weak base, magnesium hydroxide has a mild pH value, and even if it is used in excess, it will not cause serious alkaline pollution, ensuring environmental safety. Its excellent adsorption capacity and high activity can not only effectively neutralize acidic wastewater, but also accurately capture and remove heavy metal ions such as lead, nickel, copper, cadmium, etc., showing a strong heavy metal treatment capacity. In addition, the non-toxic, harmless and non-corrosive characteristics of magnesium hydroxide further simplify the wastewater treatment process, reduce dependence on anti-corrosion facilities, and thus reduce operational complexity and maintenance costs. Summary of the invention

[0005] The purpose of the present invention is to provide a high-solid content magnesium milk reagent, a preparation method and an application thereof. The magnesium milk reagent is designed by a special ratio, and high-efficiency additives such as a thickener, a stabilizer, and a surfactant are added with high-purity magnesium oxide, and is refined by a strict hydration reaction and a fine slurry preparation process.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A high-solid content magnesium milk reagent comprises the following components: 35-45 parts of high-purity magnesium oxide; 60-80 parts of water; 0.2-0.3 parts of thickener; 0.06-0.12 parts of stabilizer; 0.3-1 parts of surfactant; and 0.3-0.8 parts of dispersant.

[0008] The high-purity magnesium oxide has a MgO content of ≥90%, a CaO content of ≤5%, and a 200-mesh sieving rate of ≥98%. The added amount can be 35, 36, 37, 38, 39, 40, 41, 42, 43, 44 or 45 parts; however, the present invention is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0009] Wherein, the thickener is at least one of starch, xanthan gum, gelatin, guar gum, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, bentonite, diatomaceous earth, sodium carboxymethyl cellulose, sodium alginate, polyacrylamide, polyethylene oxide, and carbopol resin. The amount thereof can be 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29 or 0.3 parts; however, the present invention is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0010] Wherein, the stabilizer is at least one of 2-aminocyclohexanol, ethanolamine, polyvinyl alcohol, fumed silica, sodium bentonite, silicone gel, polyvinyl pyrrolidone, sodium polyacrylate, polyacrylic acid, and polyacrylate. The above compounds are used alone or in combination to form a protective layer on the surface of suspended particles through their high specific surface area characteristics, effectively preventing particle agglomeration and significantly improving the stability of the suspension. Moreover, the addition amount can be 0.06, 0.07, 0.08, 0.09, 0.10, 0.11 or 0.12 parts; however, the present invention is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0011] The surfactant is at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, hexadecyltrimethylammonium bromide, methyl methacrylate, Tween 20, Tween 80, betaine type, fatty alcohol ether, and fatty alcohol ester. The amount of the surfactant can be 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1 part; however, the present invention is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0012] After sodium dodecyl sulfate and sodium dodecylbenzene sulfonate are added to the suspension, their molecules will quickly adsorb on the interface between the suspended particles and the liquid. The hydrophilic sulfate (sulfonic acid) and sodium ions are oriented toward the water phase, while the hydrophobic dodecyl chains are oriented toward the surface of the suspended particles. This directional arrangement reduces the interfacial tension and promotes the wetting and dispersion of the suspended particles.

[0013] Tween (also known as polysorbate) is a polyol non-ionic surfactant; it is commonly used as an emulsifier, solubilizer, wetting agent, dispersing / suspending agent, and has a good dispersing effect on corrosion inhibitors.

[0014] Fatty alcohol ether is a non-ionic surfactant with high stability, which plays an emulsifying and dispersing role and is conducive to the uniform mixing of corrosion inhibitors. Fatty alcohol ester is a polyoxyethylene non-ionic surfactant with wetting, emulsifying, solubilizing and dispersing effects.

[0015] The use of surfactants can make the dispersant and stabilizer mixed more evenly, thereby further ensuring that the suspension has good fluidity and stability. The magnesium milk reagent of the present invention can be stably stored for up to six months under static conditions without any sedimentation, which greatly improves the practicality and durability of the product.

[0016] The dispersant is at least one of vinyl bisstearamide, stearic acid monoglyceride, tristearate glyceride, stearic acid, microcrystalline wax, zinc stearate, magnesium stearate, sodium pyrophosphate, potassium pyrophosphate, ethylene-acrylic acid copolymer, and calcium stearate. The amount of the dispersant can be 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8 parts; however, the present invention is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] The glycerol molecules and stearic acid molecules in monostearin and tristearin molecules are connected by ester bonds and have a unique hydrophile-lipophile balance (HLB value), which enables them to form a stable hydrated dispersion in water and a good emulsified system with oily substances.

[0018] Stearic acid compounds such as zinc stearate, magnesium stearate and calcium stearate have certain surface activity and can reduce the surface tension between particles. At the same time, this type of compound has good compatibility with water, making the particles easier to disperse in the medium and reducing agglomeration.

[0019] Pyrophosphate compounds have a certain chelating ability and can form stable complexes with metal ions, etc. In a dispersed system, pyrophosphate can produce a charge repulsion effect through its charge characteristics to prevent agglomeration between particles.

[0020] The preparation method of the high solid content magnesium milk reagent of the present invention comprises the following steps:

[0021] (1) Primary hydration: high-purity magnesium oxide and water are mixed according to a ratio and stirred for hydration reaction;

[0022] (2) Slurry preparation: Add a thickener, a stabilizer, a surfactant, and a dispersant in the slurry obtained after hydration in order according to their weight proportions, and continue stirring for 60 to 90 minutes to finally obtain a magnesium milk reagent with a high solid content and high stability.

[0023] Furthermore, the hydration temperature in step (1) is 30-70° C. For example, it can be 30, 35, 40, 45, 50, 55, 60, 65 or 70° C. However, the present invention is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] Furthermore, the hydration time in step (1) is 4 to 8 hours.

[0025] When used, the high solid content magnesium milk reagent of the present invention is added to the acidic wastewater in a certain proportion, and the chemical reaction between magnesium ions and heavy metal ions forms insoluble metal hydroxide precipitation, thereby achieving the removal of heavy metals. In addition, the pH value of the wastewater can be adjusted as needed to optimize the heavy metal removal effect.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The magnesium milk reagent of the present invention not only has a high solid content, but also has stable performance. After standing for six months, it still maintains a uniform state, has no stratification, no gel, has excellent fluidity, and is convenient for direct use. The magnesium milk reagent of the present invention has significant advantages in the treatment of acidic wastewater and heavy metal wastewater: the pH value of the effluent generally does not exceed 9, which effectively avoids the secondary pollution problem caused by excessive alkalization; at the same time, the reagent has high activity and strong adsorption capacity, can significantly improve the reaction efficiency of wastewater treatment, reduce treatment time and cost, and has significant economic and environmental benefits.

[0028] The high-solid content magnesium milk reagent of the present invention avoids the environmental alkaline pollution risk that may be caused by traditional alkaline treatment agents by selecting magnesium hydroxide as the main component; and by selecting a high-solid content suspension for long-term stable and uniform dispersion, the reaction rate and treatment efficiency in wastewater treatment can be significantly improved, thereby reducing the energy consumption of the reagent and reducing the treatment cost. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Example 1

[0031] A high-solid content magnesium milk reagent and a method for treating acidic wastewater, comprising the following steps:

[0032] (1) Weigh the required raw materials, calculated by mass: 35 parts of high-purity magnesium oxide, 0.2 parts of sodium alginate, 0.06 parts of polyacrylic acid, 0.3 parts of Tween (80), 0.3 parts of stearic acid monoglyceride, and 80 parts of water. The MgO content of the high-purity magnesium oxide is ≥90%, the CaO content is ≤5%, and the 200-mesh sieving rate is ≥98%.

[0033] (2) Mix high-purity magnesium oxide and water and stir, control the hydration temperature to 30° C., and the hydration time to 8 h.

[0034] (3) After the hydration reaction is completed, stirring is continued. After the system is cooled to room temperature, 0.2 parts of sodium alginate, 0.06 parts of polyacrylic acid, 0.3 parts of Tween (80), and 0.3 parts of stearic acid monoglyceride are added in sequence. Stirring is continued for 90 minutes and then stopped. At this time, the obtained mixed slurry is a magnesium milk reagent with a solid content of about 43.0%.

[0035] In the case of treating chromium-containing wastewater (pH of about 4, yellow and turbid) discharged from a certain electroplating plant, the above-mentioned 43.0% magnesium milk reagent was used for comparative treatment (see Table 1 below). Compared with traditional reagents, the neutralization dosage of the magnesium milk reagent in 1L wastewater treatment is lower, and even in the case of excessive addition of magnesium milk reagent, the pH value of the supernatant after filtration can be stably controlled below 9.5, showing good pH adjustment performance. In addition, the generated precipitate is compact and dense, which is conducive to reducing the treatment and disposal costs of the precipitate in actual operation.

[0036] In summary, the 43.0% magnesium milk reagent of the present invention shows significant advantages in treating chromium-containing electroplating wastewater, which not only improves the treatment efficiency, but also reduces the energy consumption of the reagent and the cost of precipitate treatment, and has broad application prospects.

[0037] Table 1

[0038]

[0039] Example 2

[0040] A high-solid content magnesium milk reagent and a method for treating heavy metal-containing wastewater, comprising the following steps:

[0041] (1) Weigh the required raw materials, in parts by mass: 38 parts of high-purity magnesium oxide, 0.2 parts of guar gum, 0.06 parts of polyvinyl alcohol, 0.06 parts of polyvinyl pyrrolidone, 0.4 parts of sodium dodecyl sulfate, 0.6 parts of Tween (20), 0.5 parts of tristearate, and 80 parts of water;

[0042] (2) mixing high-purity magnesium oxide with water and stirring, controlling the hydration temperature to 40° C. and the hydration time to 6 h;

[0043] (3) After the hydration reaction is completed, stirring is continued. After the system is cooled to room temperature, 0.2 parts of guar gum, 0.06 parts of polyvinyl alcohol, 0.06 parts of polyvinyl pyrrolidone, 0.4 parts of sodium dodecyl sulfate, 0.6 parts of Tween (20), and 0.5 parts of tristearin are added in sequence. Stirring is continued for 70 minutes and then stopped. At this time, the obtained mixed slurry is a magnesium milk reagent with a solid content of about 44.0%.

[0044] In the case of treating chromium-containing wastewater (pH of about 4, yellow and turbid) discharged from a certain electroplating plant, the above-mentioned 44.0% magnesium milk reagent was used for comparative treatment (see Table 2 below). Compared with traditional reagents, the neutralization dosage of the magnesium milk reagent in 1L wastewater treatment is lower, and even in the case of excessive addition of magnesium milk reagent, the pH value of the supernatant after filtration can be stably controlled below 9.5, showing good pH adjustment performance. In addition, the generated precipitate is compact and dense, which is conducive to reducing the treatment and disposal costs of the precipitate in actual operation.

[0045] In summary, the 44.0% magnesium milk reagent of the present invention shows significant advantages in treating chromium-containing electroplating wastewater, which not only improves the treatment efficiency, but also reduces the energy consumption of the reagent and the cost of precipitate treatment, and has broad application prospects.

[0046] Table 2

[0047]

[0048] Example 3

[0049] A high-solid content magnesium milk reagent and a method for treating heavy metal-containing wastewater, comprising the following steps:

[0050] (1) Weigh the required raw materials, calculated by mass: 42 parts of high-purity magnesium oxide, 0.2 parts of diatomaceous earth, 0.1 parts of polyacrylamide, 0.12 parts of silica gel, 0.6 parts of sodium lauryl sulfate, 0.8 parts of tristearate, and 60 parts of water;

[0051] (2) mixing high-purity magnesium oxide with water, controlling the hydration temperature to 60° C. and the hydration time to 4 h;

[0052] (3) After the hydration reaction is completed, stirring is continued. After the system is cooled to room temperature, 0.2 parts of diatomaceous earth, 0.1 parts of polyacrylamide, 0.12 parts of silicone gel, 0.6 parts of sodium lauryl sulfate, and 0.8 parts of tristearic glycerol are added in sequence. Stirring is continued for 60 minutes and then stopped. At this time, the obtained mixed slurry is a magnesium milk reagent with a solid content of about 50.3%.

[0053] In the case of treating chromium-containing wastewater (pH of about 4, yellow and turbid) discharged from a certain electroplating plant, the above-mentioned 50.3% magnesium milk reagent was used for comparative treatment (see Table 3 below). Compared with traditional reagents, the neutralization dosage of the magnesium milk reagent in 1L wastewater treatment is lower, and even in the case of excessive addition of magnesium milk reagent, the pH value of the supernatant after filtration can be stably controlled below 9.5, showing good pH adjustment performance. In addition, the generated precipitate is compact and dense, which is conducive to reducing the treatment and disposal costs of the precipitate in actual operation.

[0054] In summary, the 50.3% magnesium milk reagent of the present invention shows significant advantages in treating chromium-containing electroplating wastewater, which not only improves the treatment efficiency, but also reduces the energy consumption of the reagent and the cost of sediment treatment, and has broad application prospects.

[0055] Table 3

[0056]

[0057]

[0058] Example 4

[0059] A high-solid content magnesium milk reagent and a method for treating heavy metal-containing wastewater, comprising the following steps:

[0060] (1) Weigh the required raw materials, in parts by mass: 45 parts of high-purity magnesium oxide, 0.3 parts of sodium hydroxymethyl cellulose, 0.12 parts of silicone gel, 1 part of sodium lauryl sulfate, 0.8 parts of tristearate, and 70 parts of water;

[0061] (2) mixing high-purity magnesium oxide with water, controlling the hydration temperature to 70° C. and the hydration time to 8 h;

[0062] (3) After the hydration reaction is completed, stirring is continued. After the system is cooled to room temperature, 0.3 parts of sodium hydroxymethyl cellulose, 0.12 parts of silicone gel, 1 part of sodium lauryl sulfate, and 0.8 parts of tristearic glycerol are added in sequence. Stirring is continued for 90 minutes and then stopped. At this time, the obtained mixed slurry is a magnesium milk reagent with a solid content of about 48.2%.

[0063] In the case of treating chromium-containing wastewater (pH of about 4, yellow and turbid) discharged from a certain electroplating plant, the above-mentioned 48.2% magnesium milk reagent was used for comparative treatment (see Table 4 below). Compared with traditional reagents, the neutralization dosage of the magnesium milk reagent in 1L wastewater treatment is lower, and even in the case of excessive addition of magnesium milk reagent, the pH value of the supernatant after filtration can be stably controlled below 9.5, showing good pH adjustment performance. In addition, the generated precipitate is compact and dense, which is conducive to reducing the treatment and disposal costs of the precipitate in actual operation.

[0064] In summary, the 48.2% magnesium milk reagent of the present invention shows significant advantages in treating chromium-containing electroplating wastewater, which not only improves the treatment efficiency, but also reduces the energy consumption of the reagent and the cost of sediment treatment, and has broad application prospects.

[0065] Table 4

[0066]

[0067]

[0068] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high solid content milk of magnesia reagent, characterized in that: The invention comprises the following components: 35-45 parts of high-purity magnesium oxide; 60-80 parts of water; 0.2-0.3 parts of thickener; 0.06-0.12 parts of stabilizer; 0.3-1 parts of surfactant; and 0.3-0.8 parts of dispersant.

2. The high solid content milk of magnesia reagent according to claim 1, characterized in that: The high-purity magnesium oxide has a MgO content of ≥90%, a CaO content of ≤5%, and a 200-mesh screening rate of ≥98%.

3. The high solid content milk of magnesia reagent according to claim 1, characterized in that: The thickener is at least one of starch, xanthan gum, gelatin, guar gum, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, bentonite, diatomaceous earth, sodium carboxymethyl cellulose, sodium alginate, polyacrylamide, polyethylene oxide, and carbopol resin.

4. The high solid content milk of magnesium reagent according to claim 1, characterized in that: The stabilizer is at least one of 2-aminocyclohexanol, ethanolamine, polyvinyl alcohol, fumed silica, sodium bentonite, silicone gel, polyvinyl pyrrolidone, sodium polyacrylate, polyacrylic acid, and polyacrylate.

5. The high solid content milk of magnesia reagent according to claim 1, characterized in that: The surfactant is at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, hexadecyltrimethylammonium bromide, methyl methacrylate, Tween 20, Tween 80, betaine type, fatty alcohol ether, and fatty alcohol ester.

6. The high solid content milk of magnesia reagent according to claim 1, characterized in that: The dispersant is at least one of vinyl bisstearamide, stearic acid monoglyceride, tristearic acid glyceride, stearic acid, microcrystalline wax, zinc stearate, magnesium stearate, sodium pyrophosphate, potassium pyrophosphate, ethylene-acrylic acid copolymer, and calcium stearate.

7. The method for preparing the high solid content magnesium milk reagent according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Primary hydration: high-purity magnesium oxide and water are mixed according to a ratio and stirred for hydration reaction; (2) Slurry preparation: Add a thickener, a stabilizer, a surfactant, and a dispersant in the slurry obtained after hydration in order according to their weight proportions, and continue stirring for 60 to 90 minutes to finally obtain a magnesium milk reagent with a high solid content and high stability.

8. The method for preparing the high solid content magnesium milk reagent according to claim 7, characterized in that: The hydration temperature in step (1) is 30-70°C.

9. The method for preparing a high solid content milk of magnesium reagent according to claim 7, characterized in that: The hydration time in step (1) is 4 to 8 hours.

10. Use of the high solid content magnesium milk reagent according to any one of claims 1 to 6 in the removal of heavy metals from acidic wastewater.

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