TW457125B - Treatment of particulate materials - Google Patents

Abstract

There is disclosed a method of preparing a concentrated aqueous suspension of a finely ground particulate material by a multistage grinding process in which an aqueous suspension of the particulate material is passed to and treated by grinding in each of a series of grinding stages, wherein a water soluble polycarboxylate dispersing agent for the particulate material is added to the suspension at each of a plurality of dispersion agent addition sites or stages. The invention is characterised in that the aqueous suspension when treated by grinding in at least one of the grinding stages has a pH on the inclusive range 8.5 to 9.8. Using the method described, suspensions can be prepared which are rheologically stable with time, and which contain a relatively high proportion by weight of a finely divided pigment.

Description

457125 A7 B7 Consumption Cooperation of Employees of the Bureau of Standards and Loss of Standards of the Ministry of Economic Affairs, Printed by the Society V. Invention Description (1) The present invention relates to the preparation of an aqueous suspension of inorganic particulate materials, such as finely divided alkaline earth metal pigments, in particular, But it's not just a natural calcium carbonate pigment. Suspensions of alkaline earth metal pigments, especially those used in the coating process of paper. If the suspension can be processed, the required load on the equipment and the consumption of storage and transportation of the suspension can be minimized, then Ideal suspensions can be prepared at the highest solids concentrations. In many cases, if this pigment is incorporated into a paper coating composition, the particle size will be dispersed so that the "equivalent spherical diameter" ("esd") of the main part of the particle is smaller than 1 μηι This is what everyone expects. The use of this very finely divided pigment makes the resulting coated paper have a smooth and bright feel, but it also has disadvantages, usually a finer pigment at a solid concentration The suspension is more viscous than the relatively coarse pigment suspension. It has a tendency to be an aqueous suspension of fine pigments, and the colloidal structure formed during storage will increase the viscosity with time. Pigment makers are Attempt to provide a paper manufacturer with a high weight percentage of very finely divided pigments, but at the same time have a relatively low viscosity and this suspension can flow through the catheter and be pumped out by the pump, and prolong the storage time without forming condensation. Glue.-An aqueous suspension containing a high percentage by weight of pigment must also contain-a dispersant, so that the pigment "particles can be dispersed and will not aggregate in —Combine into agglomerates to form aggregates (aggreg () tes). The eighty-two swords most commonly used for this purpose include anionic polymer electrolytes, which are ethylene-based polymers or have (please read the precautions on the back first Fill out this page again) Gutter paper size 剌 + Guanshang (CNS) A4 specification (ΪΙ ^ 297mm-457125 A7 —_______ B7 V. Description of the invention (2) Copolymers of carboxylic acid groups. Usually these carboxylic acid The acid groups will be completely neutralized by alkali metals or ions. The dispersant used is especially sodium polyacrylate, whose average molecular weight is less than 20,000, and the carboxyl groups contained in it are neutralized by sodium. European Patent EA- P-0216〇02 describes a process of calcite, which involves concentrating a slurry of concentrated calcite particles into a multi-stage grinding step, that is, from an upstream grinding stage to one or more downstream grinding stages, with each downstream The grinding step is full of grinding media. The particle size of this grinding medium is smaller than the grinding medium of the previous upstream grinding step. The disclosed grinding media includes our chemical name 'oxidation name / second oxidation time, or oxidation. / Silicon dioxide. A dispersant, such as an aqueous solution of a water-soluble polyacrylate, such as sodium polyacrylate, is best added to the slurry before grinding. US Patent USA 4325514 discloses a grinding method, a mineral in the first When there is a lack of grinding media in the grinding chamber and it is ground under wet conditions. This ground mineral is further ground with a grinding medium in the second grinding chamber. A dispersant must be used in the first grinding chamber. The second grinding room can also choose to use a dispersant. The consumer cooperation of the Central Standards Bureau of the Ministry of Economic Affairs Du printed European patent EP-A--0595723 series discloses a grinding method in which one of the known minerals (such as acid-breaking office) is a layer The product (such as high soil) and a plastic pigment are ground together with a grinding reagent before and during the final grinding stage, and both are introduced into the same grinding container. The final milling stage can be processed under a colloidal protective reagent. We have found that the method described in the conventional technique, that is, the treatment of inorganic particulate materials such as calcium carbonate by a multi-stage grinding method is inappropriate, so the present invention has multiple improvements to the multi-stage grinding method. This paper size applies the Chinese National Standard (CNS) A4 specification (210X 297 male thin) 457125 A7 B7 Employee Consumer Cooperatives of the Central Government Standards Bureau of the Ministry of Economic Affairs of the People's Republic of China. 5. Description of the invention (3) According to the first viewpoint of the present invention A grinding process to prepare an aqueous suspension of fine particulate matter, wherein the aqueous suspension of fine particulate matter is placed in each of a series of grinding stages and ground, and one of the water-soluble polycarboxylate dispersants is Each of several dispersant addition sites or stages is added to the suspension, and is characterized in that when the aqueous suspension is subjected to a grinding treatment during the grinding process, its pH range is between 85 and 98. Adjust the pH in at least one of the grinding stages between 8 5 and 9 8, especially in the last stage of this grinding stage, preferably also in the penultimate stage, so that it can be used at high solids content. Compared with the grinding method in the conventional multi-stage grinding process of the effective grinding β of the suspension, the improvement of this grinding will be further described in the examples later. According to the method of the invention, the pH of the aqueous suspension in the last grinding stage is preferably between 8-5 and 9.5, especially between 88 and 92. A method for adjusting the pH to a desired range will be described later. The addition position of the dispersant according to the method of the present invention is combined with each grinding stage. Each dispersant addition site can contain a grinding container or mill, and grinding can also be performed during the grinding stage, but we generally prefer to add the dispersant to the suspension, such as the suspension Drive into a grinding stage located below the position combined with the pump. The fine particle material may include an insoluble salt of an alkaline earth metal, such as an insoluble salt of calcium. The material processed by the method of the present invention can be used as a pigment, especially a paper-based coating pigment. This pigment is a medium-sized paper (21GX 297 public capital) approved for the paper (please read the precautions on the back before filling out) (This page)-installed.

Line II · 125 125 Printed by the Consumers' Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs A7 B7 V. Description of Invention (4) A known type of coating composition. According to the method of the present invention, a dispersant is added at each position or stage so that the suspension is in a millable condition, especially when the suspension is processed in various stages of a series of milling stages. The pH of the liquid is adjusted as in the example described later. The method according to the invention can be carried out by a continuous process or a batch process. Preferably, this process is a continuous process, in which the treated aqueous suspension continuously enters the grinding stage and is carried out by the grinding containers joined together, respectively. In this continuous process, when a large amount is dropped for grinding, a finer solid material is obtained for grinding so that it can enter a suspension liquid below the grinding chain. During the grinding stage or after the last grinding stage, solids can be separated by particles of different sizes, such as sieves, so that only the finer parts can continue to function. One or more grinding vessels can be introduced at each grinding stage. For example, the first stage may be introduced into a single container and one or more subsequent stages may be plural, for example, two or three containers may be connected in series or in parallel. Grinding at each grinding stage also includes (a) the use of a known medium such as alumina or silica particles or an oxide mixing system; or (b) automatic grinding of particles without the addition of grinding media to each other . The media for grinding is included at least in the last stage of the process. In each grinding stage, the suspension is ground by the grinding medium, and is preferably ground with a particulate grinding medium, where the particles are not less than 2 mm and not less than 0.01 mm for grinding. The particles of the grinding medium are more preferably not larger than 1 mm and not smaller than 0.25 mm. Applies to Zhongguanxian (CNS) A4 specifications (21GX297) for each grinded paper size I -------- 1 " · ------------ Line (please read the notes on the back before filling this page) · The consumer cooperation of the Central Standards Bureau of the Ministry of Economic Affairs, printed by 457125 A7 I_ B7 V. imim (5) — I '~ --- After this stage, this is The ground particulate matter is separated from the grinding medium. At each addition position, the dispersant can be added in a single dose, or if the process is a continuous process, a plurality of separate doses are added continuously. Horse The method according to the invention may be carried out prior to the grinding stage by one or more other processing steps comprising at least one preliminary crushing step snail. For example, when the inorganic particles enter the first grinding stage, the particle size distribution is so large that particles with an equivalent sphere diameter less than 10 μυ! Account for at least 30% (preferably not more than 75%) of the weight and an equivalent sphere diameter less than The particle ratio will not be less than 20%. These particles can be obtained by mineral shaving, such as chalk or marble, with a diameter of up to 100 mm and a normal diameter range between 10 mm and 30 mm. Cross-cutting chips include a preliminary mixing step in a mill, such as a hammer mill or an automatic wet mill such as U.S. Patent 4,325,514 or preliminary wet milling. In the preliminary wet milling step, the solid concentration of the suspension determines whether or not a dispersant is used. If the solids concentration is above 50% by weight, a dispersant is normally used. The dispersant is here preferably a polycarboxylate in the preliminary step. For example, 'this preliminary grinding step may be any one of the following steps: — automatic wet grinding with dispersant, which has a high solids concentration (50% by weight or less, preferably 65% to 80%); — no Automatic wet grinding with dispersant, with low solid concentration (more than 50% by weight) but containing or not containing a chemical composition of the grinding medium, and this medium is different from the grinding medium of particulate matter; in this case, according to the present invention This paper size applies to the Chinese National Standard {CNS) A4 (2I0X297 mm) (Please read the notes on the back before filling out this page} Binding ^ Printed by the Consumer Standards Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs 457125 A7 ______B7 5 Explanation of the invention (6) ~~ The method of the invention requires a dehydration step, the best time is to perform before the first dispersing sword; or: dry grinding without dispersant, and then use water containing dispersant to meet or later A dispersant is added to form a suspension with a high solid concentration. The preferred method of the present invention is carried out in at least three grinding stages, of which the last three stages are medium grinding and grinding The grinding stage, each of which is performed after the addition of the dispersant. These three stages can be performed before one of the preliminary steps, such as before the preliminary grinding step described above. If a preliminary grinding step is included, then We hope that it is an automatic wet grinding step. The entire process of the present invention includes (at least) a four grinding stage process. In this two or four stage process, the first stage of the last three grinding stages is used as the feed The suspension of the device, the particle size distribution of the particulate matter in the aqueous suspension after grinding is so typical that the equivalent spherical diameter (esd) is less than 2 μm, the weight percentage is at least 20%, and one escj is less than 10 μm 'At least 30% (preferably not more than 75%), which is

Measured on a SEDIGRAPH 5000 machine manufactured by Micrometries Corporation. From the grinding stage to the next grinding stage, the feeding device has a particle with a preferred particle size distribution of eSd less than 2 μηι, which accounts for 50% to 80% of the weight to 100%, and at least 1 μηι accounts for 40 ° / 〇. Preferably, this feeding device has a particle size distribution for the next (previous) grinding stage, so that the weight percentage of esd less than 2µm will not be less than 90. / 〇 and esd less than 1μΐΏ accounted for at least 60%. According to the method of the present invention, this last grinding stage can be followed by one or the paper size to apply the Chinese National Standard (CNS) Λ4 specification (2Κ3 × 297 mm) (please read the precautions on the back before filling this page) • Crack · * 1T 457 125 Printed by the Consumer Standards Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs A7 B7 V. Description of Invention (7) Multiple steps are further processed. For example, the aqueous suspension of the milled particulate matter can be processed by froth flotation method (froth floation) described in the British patent GB22040457, and a small part of the product is separated. This detail The particles of the product, whose es (1 is less than 2 μΐη at least, and esd is less than 1 μηι are at least 60%. In the three or four grinding stages in the preferred embodiment of the present invention, the final The particulate inorganic solid matter contained in the first feed suspension of the three grinding stages is at least 40% by weight, preferably at least 50% by weight, and most preferably at least 60% by weight ( Based on its dry weight, usually at that stage, the aqueous suspension is unlikely to contain more than 80% of this particulate matter. This last stage of grinding continues until the particle size distribution of the ground particulate matter sinks into the equivalent spherical shape Particles with a diameter of less than μm account for at least 65% by weight before stopping. The particulate matter treated by the method of the present invention may include one or more of calcium carbonate 'calcium sulfate' barium sulfate or magnesium silicate, all of which are natural or synthetic , Such as precipitated or original. The preferred material is from natural ore such as chalk or marble. This original ore contains the second most content of other ingredients (for example, up to 10% by weight). ), Feldspar and quartz. According to the method of the present invention, polyacid II dispersant is added at various addition positions, which may be the same or different substances (discussed further later), preferably including a homopolymer. Or a copolymer containing one or more monomer units, where the monomer contains a vinyl or olefin group, this olefin group is made of paper. General Chinese National Standard (CNS) A4 · (21GX297 Publication ^^ 1 ^ ^ 1 II ^^ 1. 1 " * ^--I (please read the precautions on the back before filling out this page) Thread Printing A7 B7 printed by the Shellfish Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs ) Can be substituted by at least -acid group, or the water-soluble salts thereof. Suitable monomers are acrylic acid, methacrylic acid, itaconic acid, succinic acid, and fumaric acid 'cis-butyric acid Acid, cis-butene di adultery, isobutyric acid Acid, methyl transbutenedioic acid, oligomeric acid, deca-carbonic acid, dang acid, and acrylic acid. According to the method of the present invention, the amount of dispersant added at each addition position Add 10 to 100 moles of carboxylate for each spray of particulate matter. It is not important to maintain the treated suspension in a fully dispersed state during milling, but during milling, the dispersed The condition (controlled by the nature of the dispersant, the amount of dispersant added, and the pH of the treated suspension) is so uniform that the suspension is a complete fluid for grinding and a reasonable amount of energy is fed to the mill. In this respect, the sum of the energy wasted by the suspension during the grinding stage should normally not exceed 500Kw hours per ton of dry pigment. Usually the final suspension will be completely dispersed and no further dispersant needs to be added to make it fluid. The average molecular weight of the polycarboxylate dispersant measured by gel permeation chromatography using a low-angle laser light scattering detector should not exceed 20,000 and a preferred range is from 700 to 10,000. More preferably, the polycarboxylate dispersant used for each addition is a homopolymer or a copolymer consisting of repeating units and the following structures:

Ri R2

I I -CH-c-

I

COOH 11 This paper size applies to Chinese National Standard (CNS) A4 specification (210X297 mm) -----_ ---------- installation ------ ΐτ ----- 丨 line ( (Please read the notes on the back before filling out this page.) 457125 Printed by Shellfish Consumer Cooperative, Central Bureau of Standards, Ministry of Economic Affairs

A7 ______B7 V. Description of the invention () or the water-soluble salt therein, where R! Is -H, -Aik, -COOH or -COOAlk and R2 is -Η, -CH2, COOH or -Aik. Aik represents an alkyl group having 1 to 3 carbon atoms. A copolymer can also contain up to 70% of repeating units of the following structure: \ I —CH — CH — where R3 is -H, -C6H5 or -Aik and R4 is -Cl, -CN, -COOAlk or -OCOAlk ' Aik represents an alkyl group having 1 to 3 carbon atoms. Particularly preferred are water-soluble salts of homopolymers of acrylic acid, methacrylic acid, cis-butenedioic acid or fumaric acid, water-soluble salts of copolymers of two or more monomers, and benzene with benzene. Water-soluble salts of cis-butenedioic acid or fumaric acid copolymers of ethylene and vinyl acetate. The dispersant can be added in the form of an acid or a base, and the base has one or more neutralizing cations known in the art of dispersants, such as an alkali metal cation, ammonium cation, or an alkyl ammonium cation. , Wherein the number of carbon atoms of this alkyl group does not exceed 7. As described above, the method according to the present invention is preferably performed in at least three grinding stages, and each grinding stage is combined with a dispersant addition site where the dispersant is added to the aqueous suspension. The dispersant added individually each time will not exceed 50% of the total amount of dispersant added during milling. Normally, the number of dispersant addition sites will not exceed 10. Preferably, if there is D I ----------- Chai ------ 1T ------ i (please read the notes on the back before filling this page) SH (CNS) A4MM- (210X297 / ^) Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 457 1 25 A7 _____B7 V. Description of the invention (10) bonus positions, each addition to Chengdu should not exceed all of the process period (2 / DX 100)% of the bonus. Preferably, an equal amount of dispersant is added at each addition position. According to the method of the present invention, when the aqueous suspension is ground in one or more grinding stages, its pH is in the range of 8.5 to 9.8, more preferably in the pH range of 8J to 9.5, especially between 8.8 and 9.2. . We have found that it is advantageous to adjust the pH in this range for the following reasons. The conventional multi-stage grinding process uses a polycarboxylate salt as a dispersant ' such as described in European Patent EPA-0216002 and US Patent USA 4325514 ' and the remaining inspection in the aqueous phase will increase. For example, with dispersants containing sodium polyacrylate, the remaining sodium ions increase. In a multi-stage milling process, excess alkali will increase step by step. The reasons for the increase are as follows. When the dispersant reacts with this inorganic particle, the anion of the dispersant is neutralized by the cation on the particle. For example, the particle contains calcium of a calcium salt, thereby replacing the neutralizing cation in the dispersant salt and the solution. sodium. This effect increases as the particles become smaller and the total surface area of the dispersed particles increases. The present invention does not incorporate any theory, and this remaining base is disadvantageous for this dispersion process for the following reasons. (i) This dispersion method is related to the dispersive action of the dispersant polymer chains on the particles. The strength of the adsorption can be determined by the effect of the charge. However, the remaining base is weakened by its gravitational attraction. (ii) At least a part of the three-dimensional, balanced structure is known from the beginning. If there is too much alkali in the solution, the tendency of the polymer chain to disintegrate is increased and the three-dimensional equilibrium is weakened. η This paper size applies to China National Standards (CNS) Α4 size (210X297 mm)-II----r · -ii ^, ^ _ _ _ ___ 丁 _ 1 11 -—- 1 (Please read the back first Note: Please fill in this page again.) 25 7 Printed by the Consumers Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs, A7 B7, Invention Description (11) In order to confirm that the pH will not fall below the minimum limit of 8.5, we made the anion of the dispersant completely neutralized. And thereby avoid disintegration of the dispersant polymer chain by another effect, namely incomplete neutralization. By adjusting the pH to the required range, the ground particles can be dispersed more effectively ', and compared with the conventional multi-stage grinding process, more efficient grinding can be achieved. In this process, when the sodium polyacrylate dispersant for neutralization was first added, the pH of the aqueous calcium carbonate suspension was 10, and after the first stage of milling, the effective surface area of calcium carbonate increased, and the pH was increased and Maintained above 10. The step of adjusting the pH to a desired range is not necessary at all stages. Therefore, the dispersant added in the first addition stage may include a fully neutralized polycarboxylate dispersant without additional addition. A step of adjusting the pH may be performed in one or more of the later stages, especially the last stage, or it may be performed during the grinding stage or more preferably when the dispersant addition position is combined with the grinding stage. Adjustment. In the method of the present invention, the pH is adjusted to a desired range (in those stages where pH 値 needs to be adjusted) in one of various methods apparently used in the conventional art for treating inorganic mineral suspensions. Therefore, in the first embodiment of adjusting the pH [, a dispersant of a water-soluble acid is added to the suspension, followed by a test such as sodium hydroxide. When the particles become smaller, the number of available cations on the surface of the treated particles increases, so that the amount of alkali added is not only added in one stage, but also can be reduced step by step, so that the aqueous phase The pH is maintained in the desired range. In the second embodiment, a kind of polycarboxylate salt, for example, the polycarboxylic acid paper is again applicable to the Chinese National Standard (CNS) A4 specification (2i0 × 297 mm) I.--n I n; on i? ^ 1 ^ Ding -----'—— r U3. 、-卩 Fa (Please read the notes on the back before filling out this page) Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 457125 A7 ___B7 V. Description of the invention ( 12) Sodium, sodium polycarboxylate is added at each addition position or stage and at a stage where the pH needs to be adjusted. This aqueous medium is diluted with water to reduce its pH 値, and then preferably through a known The dehydration step is reconcentrated, such as filtration. The method of dilution and the method of reconcentration are described in the applicant's UK patent PCT / GB95_563 (world patent WO / 95 / 25M6). This dilution and concentration step is not only applied in one stage, the dilution step is mostly used in later stages. In a third embodiment, different dispersants are added to different addition stages. Therefore, in the first addition stage, a completely neutralized polycarboxylate can be added as a dispersant (without other pH adjustment steps), but in one or more of the later stages, especially the last addition stage, Add an acid type dispersant. The basic polymers or copolymers of different dispersants are preferably the same in each embodiment. In a fourth embodiment, different dispersants are added in the same addition stage, for example in one or more stages in the middle and / or in the last stage. The different reagents may include a fully neutralized polycarboxylate and an acidic polycarboxylate, which are added to the stage one after the other. The basic polymers or copolymers of different dispersants are preferably the same in each example. In a fifth embodiment, a partially neutralized polycarboxylate is added to the last stage and optionally to one or more intermediate stages. The partially neutralized polycarboxylate for the pigment as a dispersant is known in itself, and examples are known from Japanese Patent JP55-407 丨 5. Reagents used when grinding mineral materials, such as CaC03 in aqueous media, are in the US patent US-A-4840985 15 national standard (CNS ~ y ^^ ~ 21〇x297) * Paper 1τ- ------ line (please read the notes on the back before filling this page) Printed by the Consumers Cooperative of the Standards Bureau of the Ministry of Economic Affairs 457125 A7 B7 V. The description of the invention (13) is also described. However, the method described in the description is applied to a single stage and the particulate mineral material processed under the conditions of the description is rough, and the neutralized reagent is added to the grinding medium, and the neutralization is added. The degree of neutralization of the reagent is in the range of 40% to 96%. Conversely, if using the method carried out by the present invention, we consider that in the best case, the partially neutralized polycarboxylate dispersant in Example 5 is added, that is, in the stage where the suspension lacks a grinding medium, such as At a pump position, and in the middle or final grinding stage, dispersant is added when the micro-information and the substance are fine, that is, the weight percentage of the substance with esd less than 2μΐη accounts for more than 50%, and the degree of neutralization of the reagent Join below 30%. In this embodiment, the first dispersant added before the milling may include a fully neutralized polycarboxylate. It is preferred to use partially or completely neutralized poly post-acids in different addition stages, which have the same basic polymer or copolymer, such as sodium polycarboxylate. The pH in Examples 1 to 5 is adjusted within the range. When the aqueous suspension is agitated or stirred, the dispersant and other adducts (if any), and the alkali in Example 1 are also added at the same time. . The pH of this aqueous suspension will be very fast and will be adjusted to the range almost instantaneously. The pH of the suspension is measured by a pH meter as in the example. The pH can be adjusted to the required consumption range by the amount of dispersant added and / or the amount of neutralizing substance added. This adjustment step uses an automatic mechanical addition device to adjust the pH value measured under the tight line control. According to an embodiment of the present invention, there is provided a method of grinding an alkaline earth metal pigment, including the following steps: ⑴ forming an aqueous suspension containing at least 40% by weight of a rough surface paper size. Binding 1 order ---- --- Line (Please read the precautions on the back before filling this page)

Printed by the Consumer Standards of the Central Standards Bureau of the Ministry of Economic Affairs II 457125 A7 ^ _ B7 V. Description of the invention (14) Particulate soil test metal pigments and a polycarboxylate dispersant for pigments, essentially polycarboxylate dispersant The carboxylic acid group is in a neutralized state; (ii) grinding the suspension formed in the second step in the first grinding mill; (iii) removing a part of the Milled suspension with a particle size distribution of 50% to 80% by weight of particles with an esd of less than 2 μηι; (iv) adding an effective amount of a polycarboxylate dispersant to the portion removed from the first grinding mill (V) processing the portion removed from the first grinding mill, and adjusting the pH to be in the range of 8.5 to 9.8; and (v〇 grinding the second grinding mill after steps (lv) and (v) The resulting suspension. Feng Junkan adjusts the pH to the desired range with a bulk powder, and steps (iv) and (v) can be performed in a single step. Steps ⑴ to ㈣ can also be used as-the preferred three The grinding phase or part of the four grinding phase methods are carried out. In this case, the steps with the steps can be It is applied before each of the last two grinding stages. The present invention may prepare an aqueous fluid suspension of inorganic particulate matter: for example, a very finely divided aging earth metal pigment, which is prepared with the traditional Wanshi 7, Compared with suspensions, such as the European patent EpA- and the Wu Guo patent USA-43255M, the rheological properties have been improved. Therefore, the rheological properties are very stable when the preparation time is changed, and the hydration fluid is stable. Very fine pigments occupy a very high weight percentage. This secret rule is quite a wealth I ------------ m— (Please read the notes on the back before filling in this I) -IT. ^ ~- --------------- 17 4 5 7 1 2 5 Α7 Β7 Printed by the Consumers' Cooperative of the China Standards Bureau of the Ministry of Economic Affairs 5. Description of the invention () 5) (if 60% of the above % By weight), that is, the particle size distribution of this pigment is equivalent to spherical, and particles smaller than 1 μm account for 60% or more of the weight. In the present invention; where appropriate, the obtained aqueous suspension of fluid is so stable, Make the particle size distribution of equivalent spherical diameter less than 2μβι at least 80% by weight, preferably even at least 90% It is higher and the solids in the suspension account for 70% or more by weight. However, the suspension formed by the present invention may also be conventional, for example, it contains particles with an esd ratio] μιη and the weight ratio ranges from 60% to 80%. %, And the fluid properties have been improved. According to the second aspect of the present invention, it provides a very fine-grained particulate matter whose particles with an equivalent sphere diameter of less than 2 μm account for at least 90% of the weight, according to the present invention! The particle material produced by the method of this viewpoint has an equivalent sphere diameter of less than 1 μm. Particles account for at least 60% by weight, and hopefully, 75%. This substance is an aqueous suspension or a dry type (the material obtained after drying this material after treatment is useful for the user's transfer). In order to make the present invention easier to understand and how it works, a flowchart diagram is drawn according to the method of the embodiment of the present invention, such as the first figure. The method device in the diagram includes a dry rotary drum mill 1 having a perforated seat (not shown). A duct 2 guides the ground particles to the ground metal pigment and moves it from the upper part of the grinder 1 to the cyclone 3. The cyclone 3 returns the incompletely ground particles to the grinder 1 from the place where the material is ground. The sufficiently ground particles are sent to the mixing tank 5 through the duct 4. Water is injected into this mixing tank 5 via a guide 6 and a first dispersant is injected into it via a conduit 7. The function of pump 8 is to transfer the materials in the mixing tank 5 to the wet grinder 1 through the duct 9 ^ ^ will be larger through the pump 8 and the duct 7 (please read the precautions on the back before filling this page)

I I-I I — ^ 1 · Installation line The paper size is applicable to Chinese National Standard (CNS) A4 standard (210 X 297 public director) 457125 Μ Α7

5. Description of the invention (Ιό) '.dU The first dispersant was introduced into the suspension. In the first wet grinder 10, the soil metal pigment is ground and ground D in a grinding medium and a sieve 11 is provided at the bottom of the grinder 10. A pump 12 draws the milled suspension through a sieve 11 and then a pipe 13 to a second wet mill 14. This grinding medium is held there by the sieve 11 and does not pass into the wet mill 14, and a large amount of the second dispersant flows through the conduit 15 and the pump 12 and is sent into the suspension. In the second fishing grinder 14, the face metal pigment is further subjected to wet grinding under a grinding medium. This second grinder 14 has a sieve 16 and a combined pump 17 which pulls the ground suspension through the screen 16 and transfers the suspension from the duct 18 to the third wet grinder 19 . This grinding medium is still kept at the sieve 16 'and does not pass into the third wet grinder 19g. It is printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs. A large amount of the third dispersant can be passed through the conduit 15a to the pump 17. In the third wet mill 19, this alkaline earth metal pigment is further subjected to wet grinding in a grinding medium. The finely divided suspension of abrasive material flows through a sieve 20 (leaving the grinding medium) and a duct 21 to reach a froth floation cell 22. The method of froth flotation is based on British patents. The method described in the instruction No. 2204574 is performed without suspension of the suspension, and no collection reagent is added. A fine air bubble flows upward to the suspension of the flotation cell and removes carbonaceous pollutants such as foam from the suspension at 23. The alkaline earth metal pigment suspension, which is substantially free of carbonaceous contaminants, is passed through a conduit 24 and a screen 25 which removes coarse contaminants. The suspension flowing through the sieve 25 remains in the storage tank 26. The first, second, and third dispersants delivered in the process diagram through the conduits 7, 15, and 153, respectively, may be the same or different compounds. 19 Printed by Shellfish Consumer Cooperative, Central Bureau of Standards, Ministry of Economic Affairs, 457125 V. Description of the invention (17) Do not add the second and third dispersants at the 12'17 position of the pump. The pH value of the suspension will be as described above. The method was adjusted in the range of 8.5 to 9.5. The pH value of the suspension in the examples is measured by a pH display, and the amount of dispersant and / or the amount of neutralizing substance is added to adjust the pH until the desired pH is reached. This adjustment can be automatically adjusted by a mechanical addition device 'under a closed loop control using the measured pH value. Brief description of the drawings Figure 1 shows a flowchart of the grinding process. The main part represents the symbol 1 ~ dry rotary drum mill '2 ~ pipe, 3 ~ cyclones, 4 ~ pipe, 5 ~ mixing tank, 6 ~ pipe, 7 ~ pipe, 8 ~ pump, 9 ~ pipe, 10 ~ 第A fishing grinder '11 ~ sieve, 12 ~ pump, 3 ~ duct, 14 ~ second wet grinder, 15 ~ duct, 15a ~ duct, ~ sieve, n ~ pump, 18 ~ duct, 19 ~ section Three wet grinder, 20 ~ sieve, 21 ~ duct, 22 ~ froth flotation cell '23 ~ suspension, 24 ~ duct, 2S ~ sieve, 26 ~ storage tank. We can refer to the following examples to illustrate the invention. Example 1 A marble chip having a size of about 10 mm was ground in a dry rotary drum grinder to reduce the particle size distribution so that all particles were smaller than 5 claws. The prepared suspension contains approximately 71% by weight of dry marble and 12.8 moles of carboxyl groups per ton of dry marble, which is a polycarboxylate dispersant, with an average molecular weight of 6,500 and most of the carboxylic acid groups. Both were neutralized by sodium, and the suspension of '(dispersing agent 1) β was introduced into the first grinding mill. Furthermore, all papers with carboxyl 20 are suitable for use.] Standards (CNS) Congwaki (2,297 yuan) ---- I .-------- V ------, 玎- ----- {谙 Read the precautions on the back before filling this page} Early Λ V Howl 7. UR7 correction.

457125 V. Description of the invention (17- $ acid groups are neutralized by polyisocyanate dispersant (dispersant 0 added to the pump before the first grinding mill. Marble and size range 0 to 1.0 Millimeter grinding particles—from grinding, the weight ratio of grinding particles to marble is 2: 1. The suspension is beaten into a second grinding mill, and then to the grinding grinding mill. The second and third grinding mills are respectively Inject some polycarboxylate dispersant into the pump before pulverizing the grinder. The suspension can be treated by one of one methods, method A is to add dispersant 1 in all stages without other treatments, and method B is to The suspension in the pump has no other treatment 'Add dispersant 1 to the first mill and then add a similar dispersant in the next pump' but I. H-I 1 1 n----of this suspension -i—. ^ 1, I, π (please read the note on the back and fill in this page) The paper size of the printed paper is applicable to China National Standard (CNS > A4 size ( 210 X 2ί »7mm) Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 457125 A7 _____ B7 V. Description of the invention (18) The pH is also adjusted to about pH 9. Samples A1 and A2 are prepared by method A and sample A3 are prepared by method B. During the grinding stage, the suspension is heated to cause water vapor generation. So add Water keeps the solid content within the range of 76-79% by weight. The fine bubbles of air are used to turn the suspension into a froth flotation and remove the carbonaceous matter from the mud. From the froth flotation, any unwanted products can be produced. The sample of the product suspension was cooled to room temperature, followed by a standard mixing process and after stirring and after 1 hour and 24 hours, it was measured with a Bronzefield viscometer at 00 rpm. Viscosity. (TQ, Ti, and T24). The obtained results (samples A1-A3) are listed in Table 1. In addition, during the grinding process, the pH of the suspension at different stages was measured; the results are shown in the table. See Table 2. It can be seen that according to the method of the present invention, adding a polycarboxylate dispersant and adjusting the pH during the grinding process can obtain the results of low viscosity and high solid content. Controlling pH and preparing samples in Sample 3 Comparison of A1 and A2, lower viscosity Less gelatin (more fluid), a higher solids content can be obtained. Example 2 The same marble suspension as in Example 1 was prepared by the same preparation method as in Example I. However, the grinding was continued so that the equivalent spherical diameter of the particles was less than 1 um 80% by weight (determined by a standard gravity precipitation technique). The sample of the suspension is cooled to room temperature, and then enters the standard stirring process. After stirring and 1 hour and 24 hours after mixing, use Brookfield The viscosity meter measures its viscosity at 100 rpm, and the results obtained (samples B1 to B5) are listed in Table 1 and shown below. 21 CNS) A4 specification (210X 297mm) ------- install ------, order ------ 0 (Please read the precautions on the back before filling this page) 457125 Central Ministry of Economic Affairs橾 Single bureau shellfish consumer cooperation print 22 ------- A7 B7 V. Description of the invention (19) 0 In addition, the pH value of the suspension is measured at different stages in the grinding process.于 表 2。 In Table 2. It can be seen that comparing the pH adjustment (samples B4 and B5) with the samples (Bl, B2 and B3) without pH adjustment during preparation, the former suspension has more fluid and higher solid content Compared with the first pigment, the obtained pigment has a finer particle size distribution. Example 3 The same marble suspension in Example 1 was prepared by the same preparation method as in Example 1, and the polycarboxylate dispersant in Example 1 was added to form the corresponding samples Al, A2 or A3, and An appropriate amount is injected into the pump in the second grinding stage. Continue grinding until the equivalent spherical diameter is less than 90 μm of the particles. / 〇 (measured by standard gravity precipitation technology). The sample of the suspension was cooled to room temperature, injected into a standard stirring process, and its viscosity (τ (), T) was measured at 100 rpm with a Brookfie 丨 d viscosity meter after stirring and 1. hour and 24 hours after searching. ! And T24). The results obtained (samples C1 and C2) are listed in Table 1. In addition, the ρ Η 测 of the suspensions measured at different stages in the grinding process are shown in Table 2. Therefore, it can be seen that when the pH of the method (sample C2) of the present invention is adjusted during the grinding process and a polycarboxylate dispersant is added, a very fine product with a lower viscosity can be obtained. This also means that compared with the sample (C1) without the pH adjustment step when preparing the sample, the method of the present invention can obtain and a very fine, fluid product. This paper size applies to China National Standard (CNS) A4 specification (21 × 297 mm) ----------- Heyi -------, 玎 ------ ^ (Please Read the precautions on the back before filling in this page ― 457125 V. Description of the invention (20) Table 1 Weight of carboxyl solid PSD per ton of mineral sample 1 μηι viscosity mPas Total number of doses% Andreasen Total Dose moles carboxyl T〇Τι Τ24 / dry tone mineral A1 47.8 76 65 205 460 695 A2 57.4 78 65 340 570 820 A3 57.4 78 65 165 215 320 BI 77.6 76 80 270 550 900 B2 82.9 79 80 680 1140 2200 B3 82.9 78 80 450 840 1460 B4 79.8 79 80 315 425 550 B5 79.8 78 80 230 300 400 C1 76.6 75 90 280 945 2490 C2 88.3 75 90 220 305 455 (Please read the precautions on the back before filling out this page)-installed. -S Central Standard Printed by the Consumer Affairs Cooperative of the Bureau. Sample 2 pH of the final product suspension of the first mill and the second mill. PH 値 pH 値 pH 値 _ A] 10 10 10 A2 10 10 10 A3 10 9.1 9.1 Bl 10 10 10 B2 10 10 10 B3 10 10 10 B4 10 8.9 8.9 B5 10 8 9 8.9 Cl 10 1 0 10 C2 10 8.9 8.8 23 lines The size of this paper applies the Chinese National Standard (CNS) Λ4 specification (210X297 mm)

Claims (1)

457125 457125 6. Scope of patent application One or more monomers derived from acrylic acid, methacrylic acid, cis-butenedioic acid and fumaric acid. As for the copolymer, it is used together with stupid ethylene or vinyl acetate. 8. According to the scope of patent application! The method of claim, wherein the dispersant added at the addition site or stage combined with the first grinding stage comprises a fully neutralized polycarboxylate salt. 9. The method according to item 丨 of the scope of patent application, wherein the dispersant added at the addition position or stage contains a polycarboxyphosphonium salt having the same polymer structure. 10. The method according to the scope of claims 1, 8, and 9, wherein the dispersant added at the last dispersant addition position or stage contains a water-soluble acid, and an alkali reagent is added followed by the reagent. . 11. The method according to claims 1'8 and 9 of the scope of patent application, wherein the dispersant added at least at the last dispersant addition position or stage comprises a salt of a water-soluble acid, and the suspension contains water Dilute and reconcentrate. 12. The method according to claims 1, 8 and 9 of the scope of patent application, wherein the dispersant added at least in the last dispersant addition stage includes completely neutralized salts and (b) -water-soluble acid, and one by one Join one by one. 13. The method according to item 1) 8 and 9 of the scope of patent application, wherein the dispersant added at least at the last dispersant addition position or stage contains a part of the neutralized water-soluble polycarboxylate, and the neutralized The acid group does not exceed 30%. 'The dispersant is added to the suspension before the grinding stage associated with it. This suspension contains fine particles and the particle's equivalent sphere diameter is less than 2 μm and at least 50% by weight. 14. The method according to item 1 of the scope of patent application, wherein the dispersant added at each addition position or stage comprises a polycarboxylate. ______25 This paper size applies to Chinese National Standard (CNS) A4i (21D X 297 mm) ^ ---- < Guess to read the precautions on the back before filling in this page) ^ -------- ^- ----- --- M Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs ABCD 457125 VI. Application for patent scope 15. According to the method of the scope of patent application No. 1, the texture of the aqueous suspension or dry type is very fine Particles of particulate matter with an equivalent sphere diameter of less than 2 μιη account for at least 90% by weight, and particles with an equivalent sphere diameter of less than 1 μm account for at least 60% by weight. · (Please read the precautions on the back before filling out this page) Printed clothing for the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 26 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)