Multifunctional fertilizer and preparation method thereof

Abstract

The invention provides a multifunctional fertilizer and a preparation method thereof, and belongs to the technical field of fertilizer production. The multifunctional fertilizer provided by the invention is prepared from 10 to 30 percent of a material A, 20 to 40 percent of a material B, 30 to 50 percent of a material C, 1 to 2 percent of Span-80, 4 to 5 percent of Tween-80, 1 to 2 percent of white carbon black, 1 to 3 percent of magnesium aluminum silicate, 0.01 to 0.15 percent of xanthan gum, 0.03 to 0.05 percent of Kathon, 0.004 to 0.006 percent of a de-foaming agent and the balance of de-ionized water, wherein the material A comprises turf, a functional substance, calcium acetate and alkyl glycoside; the material B comprises an active strain and an auxiliary agent; and the material C comprises vitamin E, methyl esterified soybean oil, isocyanate, a fatty alcohol ether phosphate solution, EO-PO block polyether, a polyvinyl alcohol solution, ethylene glycol and formaldehyde. According to the invention, by adjusting the formula composition and the preparation process, the controllability of the generation conditions of the pore diameter and the pore density of the surface of the microcapsule is realized, and finally the controllable release of the core material is realized.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizer production, and in particular to a multifunctional fertilizer and a preparation method thereof. Background Art

[0002] The utilization rate of fertilizers in the process of plant cultivation is usually low. A large amount of fertilizers cannot be effectively utilized by the plants growing in the season or are lost in large quantities, resulting in a waste of resources. It also brings serious pollution problems, such as soil compaction and eutrophication of water bodies. In addition, due to the limitation of raw material solubility, the content of effective ingredients in existing water-soluble fertilizers is low, and when the solubility of the raw materials is close to the upper limit of solubility, water-soluble fertilizers are prone to crystallization during variable temperature storage, reducing product efficacy. It can be seen that the preparation of high effective ingredient content and the improvement of fertilizer utilization are of great significance to my country's economic development.

[0003] Microencapsulation technology refers to a technology that uses physical, chemical or physicochemical methods to encapsulate solid, liquid or gas core materials in membrane materials. Due to the isolation effect of the membrane material (capsule shell), it can effectively avoid direct contact between the core material and the external environment, reduce the impact of external environmental conditions (such as light, temperature, pH value, oxygen, solvent, etc.) on the core material, thereby improving the stability of the core material. At the same time, the presence of the capsule shell gives the microcapsule the ability to control release and extend the duration of effectiveness. According to the needs of actual application conditions, the particle size of the microcapsule ranges from nanometers to micrometers, and the common shape is spherical or nearly spherical, of course, there are also a small number of irregular shapes.

[0004] The Chinese invention patent with application number 201810562516.3 discloses a tobacco-specific package fertilizer and its preparation method. The tobacco-specific organic fertilizer, according to weight percentage, its constituent raw materials include: 60%-70% of decomposed organic materials, 30%-40% of inorganic fertilizers; the decomposed organic materials are fermented from 40%-50% of dry fungus residue, 25%-33% of dry pig manure, 8%-17% of dry straw, 9%-18% of dry oil cake, 0.2%-0.5% of fermentation bacteria and 0.18%-1.05% of monoammonium phosphate; the inorganic fertilizer, according to mass percentage, its constituent raw materials include: 5%-8% of monoammonium phosphate, 13%-17% of potassium nitrate, and 12%-15% of potassium sulfate. Although this patent has the effect of promoting the growth of tobacco plants and improving the quality of tobacco leaves, it does not have slow-release properties and the utilization rate of effective ingredients is low. Summary of the invention

[0005] In view of this, the present invention provides a multifunctional fertilizer, which includes the following components by weight percentage: 10-30% of material A, 20-40% of material B, 30-50% of material C, 1-2% of Span-80, 4-5% of Tween-80, 1-2% of white carbon black, 1-3% of magnesium aluminum silicate, 0.01-0.15% of xanthan gum, 0.03-0.05% of kason, 0.004-0.006% of defoaming agent, and the balance of deionized water;

[0006] Preferably, the multifunctional fertilizer comprises the following components by weight percentage: 20% of material A, 30% of material B, 40% of material C, 1.5% of Span-80, 4.5% of Tween-80, 1% of white carbon black, 2% of magnesium aluminum silicate, 0.05% of xanthan gum, 0.04% of kason, 0.005% of defoaming agent, and the balance of deionized water.

[0007] The material A comprises the following components in parts by weight: 2-3 parts of peat, 0.5-1 parts of functional substances, 2-4 parts of calcium acetate, and 1-2 parts of alkyl glycoside;

[0008] The material B comprises the following components in parts by weight: 0.2-0.5 parts of active bacterial strains and 2-4 parts of auxiliary agents;

[0009] The material C comprises the following components in parts by weight: 0.5-1.5 parts of vitamin E, 1-2 parts of methylated soybean oil, 0.5-1.5 parts of isocyanate, 1-2 parts of fatty alcohol ether phosphate solution, 3-5 parts of EO-PO block polyether, 0.5-0.7 parts of polyvinyl alcohol solution, 2-4 parts of ethylene glycol, and 0.2-0.5 parts of formaldehyde.

[0010] Preferably, the model of the fatty alcohol ether phosphate is fatty alcohol ether phosphate MOA-3P, which is purchased from Nantong Jiuze Chemical Co., Ltd.

[0011] Preferably, the molar ratio of the repeating unit of EO (ethylene oxide) to the repeating unit of PO (propylene oxide) in the EO-PO block polyether is 5:95 to 25:75 and the number average molecular weight is 6000-8000.

[0012] Preferably, the peat can also be replaced with mineral potassium humate or biochemical potassium humate.

[0013] Preferably, the functional substance mainly plays the role of improving the stress resistance of crops, and includes at least one of a Paecilomyces variotii extract, a Penicillium erythrogenum extract, and a Sargassum extract.

[0014] Preferably, the active strain mainly plays a role in preventing soil-borne diseases and nematodes, and includes at least one of Bacillus subtilis, Bacillus subtilis amyloliquefaciens, Trichoderma harzianum and Paecilomyces lilacinus.

[0015] Preferably, the auxiliary agent includes at least one of gum arabic solution, gelatin solution, dispersant and lignin sulfonate.

[0016] Preferably, the concentration of the gum arabic solution is 10% to 50%, and more preferably, the concentration of the gum arabic solution is 10%.

[0017] Preferably, the concentration of the gelatin solution is 20% to 70%, and more preferably, the concentration of the gelatin solution is 60%.

[0018] Preferably, the isocyanate is toluene diisocyanate.

[0019] Preferably, the concentration of the fatty alcohol ether phosphate solution is 10% to 30%, and more preferably, the concentration of the fatty alcohol ether phosphate solution is 20%.

[0020] Preferably, the concentration of the polyvinyl alcohol solution is 5% to 10%, and more preferably, the concentration of the polyvinyl alcohol solution is 8%.

[0021] Preferably, the average molecular weight of the polyvinyl alcohol is 6000.

[0022] The present invention also provides a method for preparing the multifunctional fertilizer, comprising the following steps:

[0023] (1) Preparation of material A: Peat and functional substances are crushed in proportion, added into a reaction vessel in batches, stirred until fully dispersed, and then calcium acetate is added dropwise. After the addition is completed, alkyl polyglycoside is added and the pH is adjusted to 6-7;

[0024] (2) Preparation of material B: Add active strains into a reaction vessel according to the proportion, add water until fully moistened, add additives after evenly dispersing, stir evenly, and adjust the pH to 6-7;

[0025] (3) Preparation of material C: Dissolve vitamin E in methylated soybean oil in proportion, add isocyanate after complete dissolution, stir thoroughly to form a uniform solution, then pour it into fatty alcohol ether phosphate solution, perform shear emulsification to obtain an O / W emulsion, slowly add formaldehyde while stirring, continue stirring, raise the temperature to 50-70°C, keep warm and cure for 20-40 minutes, then add polyvinyl alcohol solution, EO-PO block polyether and ethylene glycol in proportion;

[0026] (4) After mixing material A, material B and material C in proportion, add Span-80, Tween-80, white carbon black, magnesium aluminum silicate, xanthan gum, defoamer, Kasson and deionized water, and stir evenly to obtain a multifunctional fertilizer.

[0027] Preferably, the preparation process of material B in step (2) comprises the following steps: adding Bacillus amyloliquefaciens to a reaction container in proportion, adding water until fully moistened, adding gum arabic solution after uniform dispersion, heating to 50-70° C., keeping warm and curing for 20-40 minutes, adding gelatin solution dropwise under high pressure conditions, and after the addition is completed, adding a dispersant, stirring evenly, and adjusting the pH to 6-7.

[0028] Preferably, both step (1) and step (2) control the viscosity of the system to be within the range of ≤200 mPa·s.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] According to the properties of different materials, the present invention reasonably selects the complex coacervation process and the interfacial polymerization encapsulation process, and uses different encapsulation materials to coat nutrients, functional substances, and active strains separately or in multiple layers. Since the coating process is carried out layer by layer, the effective isolation of different functional substances in the same product is achieved through multi-layer coating. The number of coating layers is different, and the rate of degradation and release of the coated substances is controllable. It is beneficial to maintain the activity of the strain. At the same time, through multiple coatings, the corresponding release of relevant effective ingredients in different crop growth periods is achieved, and the specific needs of nutrients and functional substances in different crop growth periods can be accurately released, which is a technical innovation of existing fertilizer products.

[0031] The present invention realizes the controllability of the conditions for generating the surface pore size and pore density of the microcapsule by adjusting the formula composition and the preparation process, and finally realizes the controlled release of the core material.

[0032] The microcapsule premix prepared by the present invention has the characteristics of triggered microcapsules and porous microcapsules. For example, the gum-based capsule skin will not be released when the soil moisture condition is good. When the soil moisture content drops to less than 20%, the gum-based capsule skin will naturally crack. After irrigation water is used again, the internal coating can be released around the soil. Crops that are replenished with water in time after drought adversity can help crops recover quickly from adversity under the action of stress-resistant functional substances, so that stress-resistant functional substances can be reasonably controlled and released according to the changes in natural conditions in the field after the crops need them and the environment is improved, which greatly reduces the degradation and performance attenuation of effective functional substances in the natural environment, significantly prolongs the fertilizer effect, reduces field fertilization operations, and saves labor and time. Reasonable controlled release according to the crop growth period improves fertilizer utilization. The present invention also solves the difficulty of field prevention and control barrel mixing, and is not prone to crystallization and deterioration. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0034] The experimental methods or test methods described in the following examples are conventional methods unless otherwise specified; the raw materials and auxiliary agents are obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.

[0035] The model of the fatty alcohol ether phosphate described in the following examples is fatty alcohol ether phosphate MOA-3P, purchased from Nantong Jiuze Chemical Co., Ltd.; the molar ratio of the repeating unit of EO (ethylene oxide) to the repeating unit of PO (propylene oxide) in the EO-PO block polyether is 5:95, and the number average molecular weight is 6000.

[0036] Example 1

[0037] The specific steps of a preparation method of a multifunctional fertilizer are as follows:

[0038] (1) Preparation of material A: Add 10 kg of crushed peat, 1 kg of Paecilomyces variotii extract and 150 kg of Sargassum extract to a reactor containing 700 kg of deionized water, stir until fully dispersed, heat the reactor to 60°C, increase the speed of the high-speed shear to 3000 r / min, start dripping calcium acetate, and reasonably control the calcium acetate dripping speed according to the viscosity increase process of the material until all 40 kg of calcium acetate is dripped and there is no obvious agglomeration or insoluble matter, then add 10 kg of alkyl glycoside, and adjust the pH value of the system to 6-7, control the viscosity of the system to ≤200 mPa·s, and make up the balance with water to 1 KL. If not used immediately, a preservative can be added in appropriate amounts, and the finished product is ready for use;

[0039] (2) Preparation of material B: Add 50 kg of Bacillus subtilis starch to a reactor containing 100 kg of deionized water, stir until the material is fully moistened, disperse it with a high-pressure homogenizer, then add 500 kg of 10% gum arabic solution, heat the reactor to 60°C, and under 0.8 MPa high-pressure homogenization conditions, drop 59 kg of 60% gelatin solution, and reasonably control the drop rate of the gelatin solution according to the viscosity increase process of the material. After the drop addition is completed, add 20 kg of dispersant NNO (sodium methylene bisnaphthalene sulfonate), cool to room temperature, adjust the pH value to 6-7, control the system viscosity to ≤200 mPa·s, and make up the balance to 1 KL with deionized water. If not used immediately, add an appropriate amount of preservatives and the finished product is ready for use;

[0040] (3) Preparation of material C: Dissolve 15 kg of vitamin E in 20 kg of methylated soybean oil, then add 15 kg of toluene diisocyanate (TDI), stir well to form a uniform solution, then pour it into an aqueous phase containing 20 kg of fatty alcohol ether phosphate, the amount of water used is 500 kg, perform shear emulsification to obtain an O / W emulsion, slowly add 5 kg of formaldehyde while stirring, keep the shear state during the process, gradually heat to 70° C., keep warm and cure for 30 min, after the reaction is complete, change to 300 r / min stirring, keep warm for 1 h to cure, then add 50 kg of 10% polyvinyl alcohol (PEG6000) solution, 50 kg of EO-PO block polyether, and 40 kg of ethylene glycol to form a vitamin E microcapsule suspension product for standby use;

[0041] (4) Add 200kg of material A, 300kg of material B, and 400kg of material C into the reactor and mix them evenly. Add 15kg of Span-80, 45kg of Tween-80, 10kg of white carbon black, 20kg of magnesium aluminum silicate, 500g of xanthan gum, and 400g of Kasson. Add the remainder with water to 1KL. Add defoaming agent appropriately during the stirring process to suppress foam and facilitate filling operation.

[0042] The key points of product quality control in Example 1 are shown in Table 1:

[0043] Table 1 Key points for product quality control in Example 1

[0044] project Index range Measured value Water insoluble matter content; g / L ＜5 0.2 pH value (1:250 dilution) 3.0～6.0 5.6 Viscosity (200mPa·s) 300～500 240

[0045] Comparative Example 1

[0046] Commercially available fertilizers: Brand 100g / L amino acid water-soluble fertilizer (product of Sinochem Syngenta Group)

[0047] Indoor potted seedling raising was adopted to carry out a comparative test of the raw efficacy of the product of Example 1 and a commercial product of the same type and a component determination test in the adult stage. The results are shown in Table 2.

[0048] Experimental method: Select transplanted seedlings with consistent growth, and measure plant height, stem diameter, and fresh weight of aboveground parts 30 days after transplanting according to the strawberry agronomic traits survey and measurement method. Also, measure the number and weight of fruits, color change rate, vitamin C content, and reducing sugar content 90 days later.

[0049] Table 2 Comparison of the bio-test efficacy of the products of Example 1 and Comparative Example 1 and the results of component determination in the mature stage

[0050]

[0051]

[0052] The bioassay showed that the plant height, stem diameter and fresh weight of the aboveground part of the plant treated in Example 1 were better than those of the same type of commercial products, reflecting that the product of Example 1 had a significant growth-promoting effect. The results of component determination in the adult stage showed that the number of fruits, average single fruit weight, color change rate, vitamin C content and soluble sugar content treated in Example 1 were better than those of the same type of commercial products, indicating that the present invention can not only significantly improve the nutritional growth state of crops in the early stage, but also improve fruit yield and quality when used throughout the growth period.

[0053] Example 2

[0054] The specific steps of a preparation method of a multifunctional fertilizer are as follows:

[0055] (1) Preparation of material A: Add 50 kg of potassium humate, 25 kg of potassium fulvic acid, 2 kg of Penicillium rubrum extract and 150 kg of Sargassum extract to a reactor containing 500 kg of deionized water, stir until fully dispersed, heat the reactor to 60°C, increase the speed of the high-speed shearing machine to 3000 r / min, start to drop calcium acetate, and reasonably control the calcium acetate drop rate according to the viscosity increase process of the material until all 40 kg of calcium acetate is added and there is no obvious agglomeration or insoluble matter, then add 10 kg of alkyl polyglycoside, adjust the pH value of the system to 6-7, control the viscosity of the system to ≤200 mPa·s, and make up the balance with water to 1 KL. If not used immediately, a preservative can be added in appropriate amounts, and the finished product is ready for use.

[0056] (2) Preparation of material B: Add 50 kg of dormant spore powder of Paecilomyces lilacinus to a reactor containing 100 kg of deionized water, stir until the material is fully moistened, disperse it with a high-pressure homogenizer, then add 300 kg of 10% gum arabic solution, heat the reactor to 60°C, and under 0.8 MPa high-pressure homogenization conditions, drop 39 kg of 60% gelatin solution, reasonably control the drop speed of the gelatin solution according to the viscosity increase process of the material, after the drop addition is completed, add 15 kg of dispersant NNO (sodium methylene bis naphthalene sulfonate), cool to room temperature, adjust the pH value to 6-7, control the system viscosity at ≤200 mPa·s, and make up the balance to 1 KL with deionized water. If not used immediately, add an appropriate amount of preservatives, and the finished product is ready for use.

[0057] (3) Preparation of material C: 7.5 kg of vitamin E was dissolved in 20 kg of methylated soybean oil, and then 15 kg of toluene diisocyanate (TDI) was added and stirred thoroughly to form a uniform solution. The solution was then poured into an aqueous phase containing 20 kg of fatty alcohol ether phosphate, with the amount of water being 500 kg. Shear emulsification was performed to obtain an O / W emulsion. 5 kg of formaldehyde was slowly added dropwise while stirring, and the shear state was maintained during the process. The temperature was gradually raised to 70° C. and the mixture was kept warm for curing for 30 min. After the reaction was complete, the stirring speed was changed to 300 r / min and the mixture was kept warm for curing for 1 h. Then 50 kg of a 10% polyvinyl alcohol (PEG6000) solution, 50 kg of EO-PO block polyether, and 40 kg of ethylene glycol were added to form a vitamin E microcapsule suspension product for standby use.

[0058] (4) Add 200kg of material A, 300kg of material B, and 400kg of material C into the reactor and mix them evenly. Add 15kg of Span-80, 45kg of Tween-80, 10kg of white carbon black, 20kg of magnesium aluminum silicate, 500g of xanthan gum, and 400g of Kasson. Add the remainder with water to 1KL. Add defoaming agent appropriately during the stirring process to suppress foam and facilitate filling operation.

[0059] The key points of product quality control in Example 2 are shown in Table 3:

[0060] Table 3 Key points for product quality control in Example 2

[0061] project Index range Measured value Humic acid content; g / L 30±3 30.5 Water insoluble matter content; g / L ＜5 1.2 pH value (1:250 dilution) 3.0～6.0 8.2 Viscosity (200mPa·s) 300～500 310

[0062] Comparative Example 2

[0063] Commercially available fertilizers: Brand 30g / L humic acid water-soluble fertilizer (product of Sinochem Syngenta Group)

[0064] Field plot tests were conducted to compare the bioavailability of the product in Example 2 with similar commercial products and to determine the components of the product in the mature plant stage. The results are shown in Table 4.

[0065] Experimental method: A solar greenhouse with uniform water and fertilizer and the same management was selected to plant cucumbers. The previous crop of the plot was tomato, and the root-knot nematode incidence was severe. Drip irrigation and fertilization were performed once during the flowering period of the first crop of cucumber and once after fruiting. 15 days after the second application, the 5-point sampling method was used to randomly sample and determine the plant height, stem diameter, fresh weight of the aboveground part, root knot index, and nematode population reduction rate.

[0066] Table 4 Comparison of the bio-test efficacy of the products of Example 2 and Comparative Example 2 and the results of component determination in the mature stage

[0067]

[0068] The bioassays show that the plant height, stem diameter and aboveground fresh weight of the plants treated in Example 2 are superior to the same type of commercially available products, indicating that the product in Example 2 has a better growth-promoting effect than that in Comparative Example 2. The results of the determination of the root knot index and the nematode population reduction rate show that the root knot index of the plants treated in Example 2 is very low, and the further determined nematode population reduction rate is also significantly higher than that in Comparative Example 2, indicating that the present invention can not only significantly improve the growth state of crops in the early stage, but also play a role in preventing and controlling root-knot nematodes when used continuously.

[0069] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A multifunctional fertilizer, characterized in that: The composition comprises the following components by weight percentage: 10-30% of material A, 20-40% of material B, 30-50% of material C, 1-2% of Span-80, 4-5% of Tween-80, 1-2% of white carbon black, 1-3% of magnesium aluminum silicate, 0.01-0.15% of xanthan gum, 0.03-0.05% of kason, 0.004-0.006% of defoaming agent, and the balance of deionized water; The material A comprises the following components in parts by weight: 2-3 parts of peat, 0.5-1 parts of functional substances, 2-4 parts of calcium acetate, and 1-2 parts of alkyl glycoside; The material B comprises the following components in parts by weight: 0.2-0.5 parts of active bacterial strains and 2-4 parts of auxiliary agents; The material C comprises the following components in parts by weight: 0.5-1.5 parts of vitamin E, 1-2 parts of methylated soybean oil, 0.5-1.5 parts of isocyanate, 1-2 parts of fatty alcohol ether phosphate solution, 3-5 parts of EO-PO block polyether, 0.5-0.7 parts of polyvinyl alcohol solution, 2-4 parts of ethylene glycol, and 0.2-0.5 parts of formaldehyde.

2. The multifunctional fertilizer according to claim 1, characterized in that: The peat can also be replaced with mineral potassium humate or biochemical potassium humate.

3. The multifunctional fertilizer according to claim 1, characterized in that: The functional substance comprises at least one of a Paecilomyces variotii extract, a Penicillium erythrogenum extract and a Sargassum extract.

4. The multifunctional fertilizer according to claim 1, characterized in that: The active strains include at least one of Bacillus subtilis, Bacillus amyloliquefaciens, Trichoderma harzianum and Paecilomyces lilacinus.

5. The multifunctional fertilizer according to claim 1, characterized in that: The auxiliary agent includes at least one of gum arabic solution, gelatin solution, dispersant and lignin sulfonate.

6. The multifunctional fertilizer according to claim 5, characterized in that: The concentration of the gum arabic solution is 10% to 50%, and the concentration of the gelatin solution is 20% to 70%.

7. The multifunctional fertilizer according to claim 1, characterized in that: The concentration of the fatty alcohol ether phosphate solution is 10% to 30%, and the concentration of the polyvinyl alcohol solution is 5% to 10%.

8. The method for preparing the multifunctional fertilizer according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Preparation of material A: Peat and functional substances are crushed in proportion, added into a reaction vessel in batches, stirred until fully dispersed, and then calcium acetate is added dropwise. After the addition is completed, alkyl polyglycoside is added and the pH is adjusted to 6-7; (2) Preparation of material B: Add active strains into a reaction vessel according to the proportion, add water until fully moistened, add additives after evenly dispersing, stir evenly, and adjust the pH to 6-7; (3) Preparation of material C: Dissolve vitamin E in methylated soybean oil in proportion, add isocyanate after complete dissolution, stir thoroughly to form a uniform solution, then pour it into fatty alcohol ether phosphate solution, perform shear emulsification to obtain an O / W emulsion, slowly add formaldehyde while stirring, continue stirring, raise the temperature to 50-70°C, keep warm and cure for 20-40 minutes, then add polyvinyl alcohol solution, EO-PO block polyether and ethylene glycol in proportion; (4) After mixing material A, material B and material C in proportion, add Span-80, Tween-80, white carbon black, magnesium aluminum silicate, xanthan gum, defoamer, Kasson and deionized water, and stir evenly to obtain a multifunctional fertilizer.

9. The method for preparing the multifunctional fertilizer according to claim 8, characterized in that: The preparation process of material B in step (2) comprises the following steps: adding amylolytic Bacillus subtilis into a reaction container in proportion, adding deionized water until fully moistened, adding gum arabic solution after uniform dispersion, heating to 60° C., keeping warm and curing for 20-40 minutes, adding gelatin solution dropwise under high pressure conditions, adding dispersant after the addition is complete, stirring evenly, and adjusting the pH to 6-7.

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