1. A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension with solid content of 10-40%; the clay is a composition formed by purified calcium bentonite mineral powder and at least one of refined sepiolite and refined attapulgite;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension; the modifier is a composition formed by sodium pyrophosphate and at least one of phosphate and gluconolactone;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

2. The method for preparing a low-viscosity composite clay thixotropic agent as claimed in claim 1, wherein the method comprises the following steps: and 6), after spray drying, carrying out jet milling to obtain the low-viscosity composite clay thixotropic agent.

3. The method for preparing a low-viscosity composite clay thixotropic agent as claimed in claim 1, wherein the method comprises the following steps: the purified calcium bentonite is calcium bentonite purified by a dry method or a wet method, and the content of purified montmorillonite is more than or equal to 85 percent; the refined sepiolite is dry-method or wet-method purified sepiolite, and the impurity content in the purified sepiolite is less than 10 percent; the refined attapulgite is attapulgite purified by a dry method or a wet method, and the impurity content in the purified attapulgite is less than 10%.

4. The method for preparing a low-viscosity composite clay thixotropic agent as claimed in claim 1, wherein the method comprises the following steps: the dosage proportion of the bentonite, the sepiolite and the attapulgite is that the bentonite: sepiolite: attapulgite = 1: (0-0.5): (0 to 0.5).

5. The method for preparing a low-viscosity composite clay thixotropic agent according to claim 1, wherein the viscosity reducer is a low-molecular-weight sodium polyacrylate with a molecular weight of 2000-10000; the amount of the sodium polyacrylate is 0.1-5% of the mass of the clay.

6. The method for preparing a low-viscosity composite clay thixotropic agent as claimed in claim 5, wherein the method comprises the following steps: the usage amount of the sodium polyacrylate is 0.5-3% of the mass of the clay.

7. The method for preparing a low-viscosity composite clay thixotropic agent as claimed in claim 5, wherein the method comprises the following steps: the using amount of the sodium polyacrylate is 2-3% of the mass of the clay.

8. The method for preparing a low-viscosity composite clay thixotropic agent as claimed in claim 1, wherein the method comprises the following steps: the amount of the sodium pyrophosphate is 1-5% of the mass of the clay, the amount of the phosphate is 1-5% of the mass of the clay, and the amount of the gluconolactone is 0.5-3% of the mass of the clay.

9. The method for preparing a low-viscosity composite clay thixotropic agent as claimed in claim 1, wherein the method comprises the following steps: the organic acid is selected from one or more of succinic acid and malonic acid, and the amount of the organic acid is 0.1-5% of the mass of the clay.

Background

Clay materials such as bentonite, attapulgite and sepiolite have unique properties, such as: the product has slip property, expansibility and adsorbability, so the product is widely applied to the fields of building materials, chemical industry, national defense, environmental protection, light industry, agriculture, composite materials and the like. The clay material is most widely applied in the field of coating, especially in the field of solvent-based coating, and the organic modified clay is used as an economic thickener, thixotropic agent and anti-settling agent, and has large consumption. Along with the increasing attention of the country to environmental protection, the solvent-based coating is increasingly replaced by the water-based coating due to the fact that a large amount of volatile solvent is used to cause environmental pollution, and particularly in recent years, along with the continuous innovation of the field of water-based resin in China, the water-based industrial coating gradually replaces the traditional paint industrial coating, so that the future development potential is huge. Clay-based mineral materials have received much attention as a good thickening, suspending, thixotropic, slip agent. Among the most interesting materials are: bentonite, sepiolite and attapulgite. The bentonite is a 2:1 type of layered silicate mineral, the basic structure of the crystal is composed of two layers of silica tetrahedron and one layer of aluminum oxide octahedron, the thickness of a single layer is about 0.96nm, the sheet layer naturally has electronegativity, and exchangeable cations are filled between the sheet layer and the sheet layer. Sepiolite belongs to the 2:1 type of layered silicate containing aqueous chains, the basic structure of the crystal of which consists of two layers of silica tetrahedrons sandwiching a layer of magnesium oxide octahedra, the magnesium oxide layers of which are arranged in a trioctahedral structure. The attapulgite also belongs to a 2:1 type aqueous chain layered structure, the basic structure of the crystal of which is similar to that of sepiolite, but the octahedral layer of which is a mixture of dioctahedron and trioctahedral. The thickening power of bentonite in the three clay materials is more than or equal to sepiolite, but the attapulgite has excellent salt resistance.

At present, the conventional clay mineral material preparation method comprises the following steps: the process comprises the steps of raw material crushing, pulping, separation and purification, sodium treatment (gelling treatment), drying and the like, and the finally obtained inorganic gel product with certain purity is called as a magnesium aluminum silicate product.

For example, patent publication No. CN104478238A discloses a method for producing a bentonite-based mineral gel. The method mainly comprises the following steps: the bentonite is crushed and pulped, a sodium agent and a polyanion compound dispersant are added to obtain ore pulp, the ore pulp is centrifugally separated to obtain purified ore pulp, inorganic salt and organic sodium salt are added to be stirred to obtain viscous slurry, and spray drying is carried out. The sodium reagent is: one or more of sodium carbonate, sodium fluoride, sodium chloride and sodium sulfate, and the polyanion is one or more of sodium polyphosphate, sodium polyacrylate, sodium polyvinyl sulfonate and sodium polysilicate. The inorganic salt is: sodium carbonate, sodium bicarbonate, sodium fluoride, lithium carbonate, magnesium carbonate, and magnesium hydroxide; the organic sodium salt is: one or more of sodium formate, sodium acetate, sodium oxalate, sodium citrate and hexamethylene diamine sodium tetraacetate. The invention emphasizes that the obtained bentonite mineral-based gel can meet the requirements of various fields on viscosity characteristics.

Also, for example, patent document CN105600798A discloses an inorganic gel of magnesium aluminum silicate with good dispersibility and a method for preparing the same. The method mainly comprises the following steps: preparing magnesium aluminum silicate pulp (clay minerals such as smectite, bentonite and bentonite), adding organic modifier, stirring, mixing, aging, and drying to obtain organic modified magnesium aluminum silicate inorganic gel; the organic modifier is as follows: any one of methyl carbamate, imine benzimidazole carbamate, 2-isopropyl carbamate, heterocyclic dimethyl carbamate, or 2-methylpropylthiocarbamate, or a combination of at least two thereof.

Also, for example, patent publication No. CN104478365A discloses a method for improving hard water resistance of an inorganic gel of magnesium aluminum silicate. Adding a modifier into powdery magnesium aluminum silicate inorganic gel, fully stirring and mixing, heating to 30-80 ℃, keeping for 5-20 min, and cooling to room temperature to obtain a modified magnesium aluminum silicate product, wherein the modifier is as follows: one or more of sodium carbonate, sodium fluoride, sodium phosphate, sodium oxalate, sodium citrate and sodium oxalate tetraacetate.

Further, as disclosed in patent publication No. CN107555445A, an inorganic gel of magnesium aluminum silicate and a method for producing the same are disclosed. According to the method, special structures of functional additives, namely sepiolite and attapulgite minerals, and a sheet structure of bentonite are mutually overlapped and pillared to form a highly-dispersed stable network structure in a water dispersion system, water molecules are removed through sublimation by adopting vacuum freeze drying, the physical structure and the molecular structure of the magnesium aluminum silicate inorganic gel are maintained, the product has excellent rehydration performance after being dried, the dispersion time of the magnesium aluminum silicate inorganic gel in the water dispersion system is shortened, and the water dispersion viscosity of the magnesium aluminum silicate inorganic gel is improved.

However, with the development of modern coating industry, high solid content and low solvent content become the development trend of coating industry. With the increase of the use proportion of the pigment and the filler, the clay of the coating system is increased, the requirements on the rheological additive are changed from the original thickening, thixotropic, anti-settling and anti-sagging to the original thixotropic, anti-settling and anti-sagging, and the requirements on the thickening are lower and lower. The traditional magnesium aluminum silicate inorganic gel product has stronger hydrophilic performance, can form a special 'card house' type structure when dispersed in water, wraps water in the structure to form a colloid state or even a paste state, and has overlarge viscosity, thereby influencing the use in a coating formula system.

Disclosure of Invention

The invention provides a preparation method of a low-viscosity composite clay thixotropic agent, aiming at the problems of overlarge viscosity of magnesium aluminum silicate inorganic gel and the like in the prior art. According to the method, the clay is subjected to surface modification by adding a proper amount of modification auxiliary agent, so that the purpose of improving the dispersion speed of the clay in a water system is achieved, and the purposes of low viscosity and high thixotropy are achieved through composite modification of several clay materials.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension with solid content of 10-40%; the clay is a composition formed by purified calcium bentonite mineral powder and at least one of refined sepiolite and refined attapulgite;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension; the modifier is a composition formed by sodium pyrophosphate and at least one of phosphate and gluconolactone;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

In the technical scheme of the invention, clay is firstly dispersed in water to prepare suspension, and then the viscosity reducer is added to reduce the viscosity of the suspension, so that the subsequent addition of various substances can be more quickly blended into a suspension system; then, the modifier is added to convert the bentonite from calcium bentonite to sodium bentonite, and the surface of the bentonite is modified, so that the bentonite can be rapidly dispersed in a water system; then, the pH value of the system is adjusted by adding organic acid, so that the sodium bentonite can stably exist in the system; finally, the thixotropic agent is prepared by spray drying. The thixotropic agent prepared by the method has the advantages of high dispersion speed, low viscosity and the like.

Preferably, in step 6), after spray drying, the low-viscosity composite clay thixotropic agent is prepared by air flow pulverization.

Preferably, the purified calcium bentonite is calcium bentonite purified by a dry method or a wet method, and the content of purified montmorillonite is more than or equal to 85%; the refined sepiolite is dry-method or wet-method purified sepiolite, and the impurity content in the purified sepiolite is less than 10 percent; the refined attapulgite is attapulgite purified by a dry method or a wet method, and the impurity content in the purified attapulgite is less than 10%.

Preferably, in the above technical solution, the usage ratio of bentonite, sepiolite and attapulgite is bentonite: sepiolite: attapulgite = 1: (0-0.5): (0 to 0.5).

Preferably, the viscosity reducer is low-molecular-weight sodium polyacrylate with molecular weight of 2000-10000; the amount of the sodium polyacrylate is 0.1-5% of the mass of the clay.

As a further optimization of the technical scheme, the usage amount of the sodium polyacrylate is 0.5-3% of the mass of the clay.

As a further optimization of the technical scheme, the usage amount of the sodium polyacrylate is 2-3% of the mass of the clay.

Preferably, the amount of the sodium pyrophosphate is 1-5% of the mass of the clay, the amount of the phosphate is 1-5% of the mass of the clay, and the amount of the gluconolactone is 0.5-3% of the mass of the clay.

Preferably, the organic acid is selected from one or more of succinic acid and malonic acid, and the amount of the organic acid is 0.1-5% of the mass of the clay.

In conclusion, the invention has the following beneficial effects:

1. according to the invention, the viscosity of the suspension is reduced by adding the viscosity reducer into the clay suspension, so that the subsequently added additives such as a modifier, an organic acid and the like can be dispersed into the system more quickly; the dried product can be kept in a finished product, and the rehydration property of the product can be improved; the product can be endowed with the characteristics of quick dispersion and viscosity reduction;

2. according to the invention, the clay is subjected to surface modification by adding a proper amount of modification auxiliary agent, so that the purpose of improving the dispersion speed of the clay in a water system is realized, and the purposes of low viscosity and high thixotropy are realized through the composite modification of several clay materials.

Detailed Description

The following detailed description is to be construed as merely illustrative, and not restrictive, and all changes that may be made by those skilled in the art after reading the specification herein are intended to be protected by the claims.

Example one

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

weighing 200g of purified bentonite mineral powder, slowly adding the purified bentonite mineral powder into 2L of water under the stirring condition, and fully stirring and dispersing for 2 hours to prepare bentonite suspension. Adding 4g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then 6g of sodium pyrophosphate is added, and the mixture is stirred and dispersed for 30 minutes; then adding 0.6g of succinic acid, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

Example two

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

weighing 200g of purified bentonite mineral powder, slowly adding the purified bentonite mineral powder into 2L of water under the stirring condition, and fully stirring and dispersing for 2 hours to prepare bentonite suspension. Adding 2g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then 6g of sodium pyrophosphate is added, and the mixture is stirred and dispersed for 30 minutes; then adding 0.6g of succinic acid, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

EXAMPLE III

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

weighing 200g of purified bentonite mineral powder, slowly adding the purified bentonite mineral powder into 2L of water under the stirring condition, and fully stirring and dispersing for 2 hours to prepare bentonite suspension. Adding 1g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then 6g of sodium pyrophosphate is added, and the mixture is stirred and dispersed for 30 minutes; then adding 0.6g of succinic acid, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

Example four

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

weighing 200g of purified bentonite mineral powder, slowly adding the purified bentonite mineral powder into 2L of water under the stirring condition, and fully stirring and dispersing for 2 hours to prepare bentonite suspension. Adding 4g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then 4g of sodium pyrophosphate and 2g of phosphate are added, and stirred and dispersed for 30 minutes; then adding 0.6g of succinic acid, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

EXAMPLE five

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

weighing 200g of purified bentonite mineral powder, slowly adding the purified bentonite mineral powder into 2L of water under the stirring condition, and fully stirring and dispersing for 2 hours to prepare bentonite suspension. Adding 4g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then adding 2g of sodium pyrophosphate and 2g of gluconolactone, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

EXAMPLE six

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

weighing 200g of purified bentonite mineral powder, slowly adding the purified bentonite mineral powder into 2L of water under the stirring condition, and fully stirring and dispersing for 2 hours to prepare bentonite suspension. Adding 4g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then adding 2g of sodium pyrophosphate and 2g of gluconolactone, and stirring and dispersing for 30 minutes; then adding 0.6g of succinic acid, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

EXAMPLE seven

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

weighing 200g of purified bentonite mineral powder, slowly adding the purified bentonite mineral powder into 2L of water under the stirring condition, and fully stirring and dispersing for 2 hours to prepare bentonite suspension. Adding 4g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then 6g of sodium pyrophosphate and 4g of gluconolactone are added, and stirred and dispersed for 30 minutes; then adding 1g of succinic acid, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

Example eight

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

weighing 200g of purified bentonite mineral powder, slowly adding the purified bentonite mineral powder into 2L of water under the stirring condition, and fully stirring and dispersing for 2 hours to prepare bentonite suspension. Adding 4g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then 6g of sodium pyrophosphate and 2g of gluconolactone are added, and stirred and dispersed for 30 minutes; then adding 2g of succinic acid, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

Example nine

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

weighing 200g of purified bentonite mineral powder, slowly adding the purified bentonite mineral powder into 2L of water under the stirring condition, and fully stirring and dispersing for 2 hours to prepare bentonite suspension. Adding 4g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then adding sodium pyrophosphate g and phosphate 3g, stirring and dispersing for 30 minutes; then adding 0.6g of succinic acid, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

Example ten

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

weighing 200g of purified bentonite mineral powder, slowly adding the purified bentonite mineral powder into 2L of water under the stirring condition, and fully stirring and dispersing for 2 hours to prepare bentonite suspension. Adding 4g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then adding sodium pyrophosphate g and phosphate 3g, stirring and dispersing for 30 minutes; then adding 0.6g of malonic acid, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

EXAMPLE eleven

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

weighing 180g of purified bentonite mineral powder and 20g of sepiolite, slowly adding the purified bentonite mineral powder and the sepiolite into 2L of water under the condition of stirring, and fully stirring and dispersing for 2 hours to prepare bentonite suspension. Adding 4g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then 6g of sodium pyrophosphate and 2g of gluconolactone are added, and stirred and dispersed for 30 minutes; then adding 0.6g of succinic acid, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

Example twelve

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

160g of purified bentonite ore powder and 40g of sepiolite are weighed, slowly added into 2L of water under the stirring condition, fully stirred and dispersed for 2 hours, and bentonite suspension is prepared. Adding 4g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then 6g of sodium pyrophosphate and 2g of gluconolactone are added, and stirred and dispersed for 30 minutes; then adding 0.6g of succinic acid, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

EXAMPLE thirteen

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

weighing 180g of purified bentonite mineral powder and 20g of attapulgite, slowly adding the purified bentonite mineral powder and the attapulgite into 2L of water under the stirring condition, and fully stirring and dispersing for 2 hours to prepare bentonite suspension. Adding 4g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then 6g of sodium pyrophosphate and 2g of gluconolactone are added, and stirred and dispersed for 30 minutes; then adding 0.6g of succinic acid, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

Example fourteen

A preparation method of a low-viscosity composite clay thixotropic agent comprises the following steps:

1) dispersing clay in water to prepare suspension;

2) adding a viscosity reducer into the suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare a pretreatment suspension;

3) settling the pretreatment suspension for 1-2 h, and removing substances deposited at the bottom to obtain a viscosity-reducing suspension;

4) adding a modifier into the viscosity-reducing suspension, and then stirring and dispersing, ultrasonically dispersing or homogenizing and dispersing under high pressure to prepare pre-modified suspension;

5) adding organic acid into the pre-modified suspension, and then stirring and dispersing, ultrasonic dispersing or high-pressure homogenizing and dispersing to prepare modified suspension;

6) and spray drying the modified suspension to prepare the low-viscosity composite clay thixotropic agent.

More specifically, the present embodiment operates as follows:

160g of purified bentonite ore powder and 40g of attapulgite are weighed, slowly added into 2L of water under the stirring condition, and fully stirred and dispersed for 2 hours to prepare bentonite suspension. Adding 4g of sodium polyacrylate into the suspension, and stirring and dispersing for 30 minutes; then 6g of sodium pyrophosphate and 2g of gluconolactone are added, and stirred and dispersed for 30 minutes; then adding 0.6g of succinic acid, and stirring and dispersing for 30 minutes; spray drying (centrifuge head rotation speed 200 HZ), and jet milling to obtain a sample.

The product of the above example was subjected to a 10% viscosity test. The results are as follows:

as can be seen from the above table, the method of the present invention can be used to prepare low-viscosity composite clay thixotropic agents with different viscosity ranges. In particular, it can be seen from examples 11 to 14 that the composite clay thixotropic agent has a lower viscosity.