CN1331755C - Process for preparing high thixotropic nano calcium carbonate - Google Patents

Process for preparing high thixotropic nano calcium carbonate Download PDF

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Publication number
CN1331755C
CN1331755C CNB2005101123724A CN200510112372A CN1331755C CN 1331755 C CN1331755 C CN 1331755C CN B2005101123724 A CNB2005101123724 A CN B2005101123724A CN 200510112372 A CN200510112372 A CN 200510112372A CN 1331755 C CN1331755 C CN 1331755C
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calcium carbonate
coating
nano
add
carbonization
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CN1792803A (en
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颜培刚
张华�
黎绍北
蔡琨
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SHANGHAI YAOHUA NANO-TECH Co Ltd
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SHANGHAI YAOHUA NANO-TECH Co Ltd
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Abstract

The present invention discloses a preparation method for high-thixotropy nano calcium carbonate, which has the steps of digestion, carbonation, coating and drying. The present invention adopts a carbonation technique, additives adopt a special coating agent and a technique, so the method is an intermittent type stirring carbonation method with the advantages of simple technical operation control and easy conversion, and prepared crystal has the advantages of good development, narrow particle diameter distribution range and high thixotropy. The nano calcium carbonate is used in coating and adhesive industry and can completely replace white carbon black of a gas phase method as a thixotropic agent.

Description

A kind of preparation method of high thixotropic nano calcium carbonate
Technical field
The present invention relates to a kind of preparation method who is used for the lime carbonate in chemistry painting industry and adhesive technology field, relate in particular to a kind of preparation method of high thixotropic nano calcium carbonate.
Background technology
Thixotropy is one of important content of dispersion system Research on The Rheology, is meant some systems under stirring or other mechanical effect, the time dependent a kind of rheological phenomena of the viscosity of system or shear force.
Positive thixotropy (Positive thixotropy) is meant that the viscosity of system under the effect of shear force outside descends in time, recovers again after static, promptly has the rare phenomenon of cutting of time factor.
Negative thixotropy is just in time opposite with positive thixotropy, is a kind of thick phenomenon of cutting of time factor that has, and is promptly adding shear force or is cutting under the speed, and the viscosity of system rises, the phenomenon of recovering again after leaving standstill.
Nano-calcium carbonate thixotropy testing method
1. the preparation of sample: accurately take by weighing 175gDOP, 100g nano-calcium carbonate, 10g calcium oxide with 3000r/s high-speed stirring 5 minutes, leave standstill in iron flask;
2. will leave standstill the sample HAARKE VT550 rheometer test of 24h, the variation program of thixotropy test shearing rate is: 0s -1→ (1min rises to) 452s -1(keeping 5min) → (1min reduces to) 0s -1
According to the long-pending thixotropy that can judge that nano-calcium carbonate DOP sticks with paste of the measured rheology anchor ring of rheometer, the rheology anchor ring is long-pending big more, shows that then the time dependent degree of yield value (or viscosity) of lime carbonate DOP paste is big, illustrates that thixotropy is good more.
Nanometer CaCO 3The thixotropic behavior mechanism of/DOP plastipaste system: from thixotropic property, along with the increase of shearing force, CaCO 3The equilibrium state of network structure is destroyed gradually between particle, and the microtexture form of system changes, and interparticle distance is drawn back, and intergranular reactive force changes attraction into by repulsion.After externally shearing force was eliminated, the intergranular magnetism of pedesis and the coacervate system that makes returned to the plan network structure of stationary state again, but recovery process needs certain hour, thereby made system embody thixotropic behavior.
Nano-calcium carbonate is widely used in coating and adhesive area, nano-calcium carbonate is applied to coating and adhesive industry, thereby the filler effect that plays traditional lime carbonate on the one hand reduces production costs, nano-calcium carbonate is as nano particle on the other hand, and the rheological property that it has has caused scientific research personnel's concern.In association areas such as coating and tackiness agent,, keep not sagging of coating for the workability that improves coating and tackiness agent has good surface appearance after making the construction of coating and tackiness agent simultaneously.In the prescription of coating or tackiness agent, the thixotropic agent of normal use is the white carbon black of gas phase, because the white carbon black of vapor phase process production has good thixotropy, so obtained using widely at coating and adhesive industry; Along with the technology of preparing of nano-calcium carbonate constantly develops, nano-calcium carbonate has had further development in the application of coating and adhesive industry, and nano-calcium carbonate has replaced the expensive white carbon black of part owing to have certain thixotropy in the prescription of coating and tackiness agent.At present, there is the crystal development imperfection in domestic nano-calcium carbonate calcium product, and the deficiency that particle size distribution range is wide causes prepared nano-calcium carbonate powder thixotropy relatively poor or do not have a thixotropy thus.
Because the nano-calcium carbonate good thixotropy and the extensive use that have, the exploitation of its preparation method and product innovation has been subjected to noticing that widely present industrial nano-calcium carbonate mainly is Ca (OH) 2-CO 2-H 2The O system, this reactive system is with Ca (OH) 2The water miscible liquid system is the calcium source, uses CO 2Carbonization obtains CaCO 3Ca (OH) 2Generally be sintered into lime, obtain through digestion then by natural whiting.The flue gas that obtains behind the calcination of calcium carbonate is after filtering as the CO that reacts 2Source of the gas by controlling different reaction conditionss, can obtain the nano-calcium carbonate powder of different crystal forms.Nano-calcium carbonate generally is the reaction of carrying out in stirred reactor, improves mass transfer, the heat-transfer effect of reaction system by stirring, importantly also must carry out strict control to reaction conditions, and main controlling factor has Ca (OH) 2Concentration, CO 2Flow, temperature of reaction, additive amount, additive joining day etc.By controlling different conditions, can access the nano-calcium carbonate of multiple crystalline structure such as sphere, cubes at present.
When but domestic nano-calcium carbonate powder is applied in coating and the tackiness agent at present, exist following problem:
1. prepared nano-calcium carbonate crystal development imperfection can not be prepared the cubes nano-calcium carbonate of complete crystallization;
2. prepared nano-calcium carbonate particle size range is wide;
3. do not find suitable surface-modifying agent, prepared nano-calcium carbonate thixotropy difference or do not have thixotropy.
Summary of the invention
Defective at the thixotropy difference of the nano-calcium carbonate that is applied to coating and adhesive industry at present, the object of the present invention is to provide a kind of preparation method of high thixotropic nano calcium carbonate, prepare that a kind of crystal development is good, particle size distribution range is narrow, have the nano-calcium carbonate of high thixotropic simultaneously.
The technical scheme that realizes objects of the present invention is as follows: the flat coexistence five principles
A kind of preparation method of high thixotropic nano calcium carbonate in turn includes the following steps:
(1), natural whiting after cleaning at first the temperature lower calcination at 900-1100 ℃ become CaO, add cold water then and be digested to Ca (OH) 2, be mixed with certain density milk of lime through control digestion water;
(2), milk of lime drops in the reactor, adds the nucleus inhibitor and stir before carburizing reagent, the add-on of nucleus inhibitor is the 0.002%-0.01% of weight of calcium carbonate, the stack gas of calcination of calcium carbonate after purifying as the CO of carbonization 2Source of the gas feeds CO 2React CO 2Volume content between 18%~20%, after form a certain amount of nucleus quantity, add the growth velocity that the crystalline form conditioning agent is controlled each crystal face in carbonization, crystalline form conditioning agent add-on is the 0.1%-0.8% of weight of calcium carbonate; Continue carbonization to terminal, add dispersion agent again and regulate the calcium carbonate slurry that the particle surface electric charge obtains good dispersity, the starting temperature of solution is controlled at 18-40 ℃ in the reaction process, when the pH of molten stream is neutrality, stopped reaction, the reaction times was about about 1.5-2.2 hour;
(3), adding coating after reaction finishes coats: coating is mixed with the aqueous solution, is warmed up to 70~90 ℃, get covering liquid lime carbonate is coated; Described coating is Ca (ST) 2With the compound coating of NaST: Ca (ST) 2: NaST=1: 2-1: 1 (the two weight ratio), the amount of coating is 2.5~3.5% of a nano-calcium carbonate weight, the coating time is 15~30 minutes;
(4), the lime carbonate after coating is carried out press filtration, drying, high thixotropic nano calcium carbonate.
The lime milk concentration of wherein said step (1) is controlled at 110~115g/l.
Wherein the nucleus inhibitor described in the step (2) is citric acid, lactic acid.
Wherein crystalline form conditioning agent described in the step (2) is a kind of in lactic acid, the sulfuric acid or the mixture of the two.
Wherein dispersion agent described in the step (2) is dodecyl triethyl amine bromide (C 12NE) and sodium lauryl sulphate (SDS), its thixotroping compositional range zone is C 12NE: SDS=1: 1-1: 2 ratio, and SDS is excessive; Or hydro-polyacrylamide (PHPA).
Coating in the wherein said step (3) is stearic acid, NaOH, Ca (OH) 2Saponification forms.
The preparation feedback equation of nano-calcium carbonate is as follows:
Processing parameter of the present invention:
The raw material: Wingdale, calcium carbonate content are greater than 98%, and whiteness is greater than 92%;
digests water: tap water;
The kiln gas of calcination of calcium carbonate: need to remove impurity and dust in the kiln gas, the CO after the purification through three sections purifications 2Gas participates in carburizing reagent after entering air compressor machine;
Ca (OH) 2Emulsion concentration is controlled at about 110~115g/l;
The reacting initial temperature is controlled at 18-40 ℃;
CO in the kiln gas 2Content between 18%~20%;
Surface charge and sterically hindered conditioning agent (dispersion agent): dodecyl triethyl amine bromide (C 12NE) and sodium lauryl sulphate (C 12S or SDS), its thixotroping compositional range zone is C 12NE: SDS=1: 1-1: 2 ratio, and SDS is excessive; The mixing total concn of the two, i.e. G Tot/ moldm -3, be 0.05/moldm -3, ratio is 1: 1.5; Hydro-polyacrylamide (PHPA), add-on 0.05%.
_ stirring velocity: 400-1000RPM
The final product quality that obtains is: crystalline form is a cubes, particle diameter 60-90nm, oil-absorption(number)<35gDop/100gCaCO 3, the rheology anchor ring amasss>70000Pa/s.
The present invention adopts special carbonization technique and additive to adopt special coating and technology, technological operation control intermittent type simple, that be easy to transform stirs carborization, prepare that a kind of crystal development is good, particle size distribution range is narrow, have the nano-calcium carbonate of high thixotropic simultaneously.This nano-calcium carbonate is applied to coating and adhesive industry, can replace thermal silica to use as thixotropic agent fully.
The present invention compares with the production technology of other nano-calcium carbonates, has following outstanding feature:
4. crystalline form is complete cubes crystalline form, and crystal development is perfect;
5. nano-calcium carbonate crystalline narrow diameter distribution is 60-90nm;
6. prepared nano-calcium carbonate powder is applied to have good thixotropy in the pvc plastisol, can replace expensive white carbon black to improve the thixotropic property of tackiness agent fully.
Description of drawings
The nano-calcium carbonate crystal TEM photo that Fig. 1 makes for the embodiment of the invention 1;
The Ma Erwen particle size distribution figure of the nano-calcium carbonate that Fig. 2 makes for inventive embodiments 1 of the present invention.
Embodiment
How further specify the present invention below in conjunction with specific embodiment realizes:
Embodiment 1
At 2m 3Reactor in add 0.8m 3Concentration is the calcium hydroxide slurry of 4% (weight concentration, being converted into calcium carbonate content concentration is 56g/l), and reacting initial temperature is controlled at 18 ℃, adds the 3.36g citric acid and stir before the reaction beginning, feeds CO then 2Content is that the kiln gas of 25% (volumetric concentration) carries out carbonization, and the kiln gas flow is 7.5m 3/ h adds 224g lactic acid behind the carbonization 0.5h, continuing carbonization to pH value again is 7, adds 0.016molC then 12S and 0.024molSDS stir 0.5h, obtain homodisperse nano-calcium carbonate slurry.
The saponification in 85 ℃ water with 1254g stearic acid and 164g dissolution of sodium hydroxide, wait the pH value stabilization after, add 77g calcium hydroxide and continue saponification 1 hour, make covering liquid, add then in the carbonization slurry, the coating time is 30 minutes.Press filtration, drying obtain nano-powder.
Obtained powder test result sees Table one:
Table one
Sample number into spectrum Yield value (Pa) Viscosity (Pas) Rheology anchor ring long-pending (* 10 4Pa/s)
1 154 0.56 8.97
Crystal morphology as shown in Figure 1, the Ma Erwen size-grade distribution is as shown in Figure 2.
Embodiment 2
At 2m 3Reactor in add 0.8m 3Concentration is the calcium hydroxide slurry of 4% (weight concentration, being converted into calcium carbonate content concentration is 56g/l), and reacting initial temperature is controlled at 25 ℃, adds the 3.36g citric acid and stir before the reaction beginning, feeds CO then 2Content is that the kiln gas of 17% (volumetric concentration) carries out carbonization, and the kiln gas flow is 10m 3/ h adds 224g sulfuric acid behind the carbonization 0.5h, continuing carbonization to pH value again is 7, adds 0.016molC then 12S and O.024molSDS stirs 0.5h, obtains homodisperse nano-calcium carbonate slurry.
The saponification in 85 ℃ water with 1254g stearic acid and 164g dissolution of sodium hydroxide, wait the pH value stabilization after, add 77g calcium hydroxide and continue saponification 1 hour, make covering liquid, add then in the carbonization slurry, the coating time is 30 minutes.Press filtration, drying obtain nano-powder.
Obtained powder B sample test result:
Sample number into spectrum Yield value (Pa) Viscosity (Pas) Rheology anchor ring long-pending (* 10 4Pa/s)
2 198 0.55 9.08
Embodiment 3
At 2m 3Reactor in add 0.8m 3Concentration is the calcium hydroxide slurry of 4% (weight concentration, being converted into calcium carbonate content concentration is 56g/l), and reacting initial temperature is controlled at 40 ℃, adds the 3.36g citric acid and stir before the reaction beginning, feeds CO then 2Content is that the kiln gas of 17% (volumetric concentration) carries out carbonization, and the kiln gas flow is 7.5m 3/ h adds 224g sulfuric acid behind the carbonization 0.5h, continuing carbonization to pH value again is 7, adds 22.4g hydro-polyacrylamide (PHPA) then, stirs 0.5h, obtains homodisperse nano-calcium carbonate slurry.
The saponification in 85 ℃ water with 1254g stearic acid and 164g dissolution of sodium hydroxide, wait the pH value stabilization after, add 77g calcium hydroxide and continue saponification 1 hour, make covering liquid, add then in the carbonization slurry, the coating time is 30 minutes.Press filtration, drying obtain nano-powder.
Obtained powder B sample test result:
Sample number into spectrum Yield value Viscosity The rheology anchor ring is long-pending
(Pa) (Pa·s) (×10 4Pa/s)
3 221 0.49 8.83

Claims (1)

  1. The preparation method of 1 one kinds of high thixotropic nano calcium carbonates in turn includes the following steps:
    (1), the natural whiting high-temperature calcination becomes CaO, add cold water then and be digested to Ca (OH) 2, be mixed with the milk of lime that concentration is 110~115g/l by control digestion water;
    (2), milk of lime drops in the reactor, adds the nucleus inhibitor and stir before carburizing reagent, the add-on of nucleus inhibitor is the 0.002%-0.01% of weight of calcium carbonate, feeds CO 2React, after form a certain amount of nucleus quantity, add the growth velocity that the crystalline form conditioning agent is controlled each crystal face in carbonization, crystalline form conditioning agent add-on is the 0.1%-0.8% of weight of calcium carbonate; Continue carbonization to terminal, add dispersion agent again and regulate the calcium carbonate slurry that the particle surface electric charge obtains good dispersity, the starting temperature of solution is controlled at 18-40 ℃ in the reaction process, when the pH of solution is neutrality, stopped reaction, the reaction times is 1.5-2.2 hour, makes nano-calcium carbonate, wherein, the stack gas of calcination of calcium carbonate after purifying as the CO of carbonization 2Source of the gas, CO 2Volume content between 18%~20%; Described nucleus inhibitor is citric acid or lactic acid; Described crystalline form conditioning agent is a kind of in lactic acid, the sulfuric acid or the mixture of the two; Described dispersion agent is dodecyl triethyl amine bromide and sodium lauryl sulphate, and its thixotroping compositional range zone is a dodecyl triethyl amine bromide: sodium lauryl sulphate=1: 1-1: 2 ratio, and sodium lauryl sulphate is excessive;
    (3), adding coating after reaction finishes coats: coating is mixed with the aqueous solution, is warmed up to 70~90 ℃, get covering liquid lime carbonate is coated; Described coating is Ca (ST) 2With the compound coating of NaST, the two weight ratio is: Ca (ST) 2: NaST=1: 2-1: 1, the amount of coating is 2.5~3.5% of a nano-calcium carbonate weight, the coating time is 15~30 minutes; Wherein, described coating is stearic acid and NaOH and Ca (OH) 2Saponification forms;
    (4), the lime carbonate after coating is carried out press filtration, drying, high thixotropic nano calcium carbonate.
CNB2005101123724A 2005-12-29 2005-12-29 Process for preparing high thixotropic nano calcium carbonate Expired - Fee Related CN1331755C (en)

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Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101967310A (en) * 2010-07-14 2011-02-09 山东海泽纳米材料有限公司 Method for preparing nano calcium carbonate with low viscosity and medium thixotropic property
CN102167915B (en) * 2011-03-03 2013-04-17 淄博嘉泽纳米材料有限公司 Preparation method of medium/low-viscosity high-thixotropy nano calcium carbonate for aqueous system
CN102732065A (en) * 2011-04-15 2012-10-17 池州凯尔特纳米科技有限公司 Preparation method of PVC special-purpose functional filler superfine active calcium carbonate with low oil absorption
CN104098928B (en) * 2014-03-17 2016-08-17 福建省万旗非金属材料有限公司 The preparation method of a kind of nano-calcium carbonate with negative thixotroping and thixotropy method of testing thereof
PL2939980T3 (en) * 2014-04-30 2018-08-31 Omya International Ag Production of precipitated calcium carbonate
CN105217673B (en) * 2015-10-21 2018-01-09 常山县南方碳酸钙有限公司 A kind of preparation method of high thixotropic silicone adhesive special-purpose nanometer activated Calcium carbonate
CN105329928A (en) * 2015-12-10 2016-02-17 湖南化工职业技术学院 Activation method for nanometer calcium carbonate
CN110028093B (en) * 2018-07-31 2021-07-20 荆门市东宝区凯龙矿业股份有限公司 Preparation and detection method of inverse thixotropic nano calcium carbonate
CN109399683B (en) * 2018-12-06 2020-12-01 东北大学 Preparation method of nano calcium carbonate for yield enhancement of PVC (polyvinyl chloride) automobile primer

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CN1085188A (en) * 1992-09-29 1994-04-13 李维家 Industrial smoke is used to produce light calcium carbonate and calcium chloride technology
CN1375456A (en) * 2002-02-07 2002-10-23 上海建筑材料集团新材料有限公司 Nano level active calcium carbonate for special use
CN1559908A (en) * 2004-03-12 2005-01-05 浙江大学 Process for water heat synthesis of nano grade cubic calcium carbonate
CN1631789A (en) * 2003-12-24 2005-06-29 上海华明高技术(集团)有限公司 Method for preparing nano calcium carbonate particle

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1085188A (en) * 1992-09-29 1994-04-13 李维家 Industrial smoke is used to produce light calcium carbonate and calcium chloride technology
CN1375456A (en) * 2002-02-07 2002-10-23 上海建筑材料集团新材料有限公司 Nano level active calcium carbonate for special use
CN1631789A (en) * 2003-12-24 2005-06-29 上海华明高技术(集团)有限公司 Method for preparing nano calcium carbonate particle
CN1559908A (en) * 2004-03-12 2005-01-05 浙江大学 Process for water heat synthesis of nano grade cubic calcium carbonate

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