A kind of nano-calcium carbonate magnesium crystal and preparation method thereof
[technical field]
The invention belongs to technical field of inorganic nanometer material, relate to a kind of nano-calcium carbonate magnesium crystal and preparation method thereof.
[background technology]
Magnesiumcarbonate (comprising magnesium basic carbonate and Carbon Dioxide magnesium) is a kind of important inorganic chemical industry material, have good filling property, dispersiveness and mobile, can improve the tensile strength and the wear resistance of engineering plastics, be the good weighting agent and the strengthening agent of engineering plastic product.Since magnesium basic carbonate have do not burn, quality is light, and it is added in the engineering plastics, can significantly improve the thermal insulation of engineering plastics, high temperature resistant and flame retardant properties.
Because micron-sized magnesiumcarbonate can occur disperseing uneven phenomenon in adding other materials to as filling additive, has a strong impact on the characteristic of other materials.
Nano-calcium carbonate magnesium has other more outstanding advantages than micron order or the magnesiumcarbonate more than the micron order, as good dispersed and with the consistency of organic materials, make it can improve the characteristic of this organic materials significantly, and can not constitute great influence again the characteristic of this organic materials itself as additive.
The method that prepare at present magnesiumcarbonate is a lot, and what still prepare mostly is micron-sized magnesiumcarbonate, and it is less to prepare nano level magnesiumcarbonate.Major cause is, the difficult preparation of nano level magnesiumcarbonate, and nano-calcium carbonate magnesium is the same with metal-oxide powder with many nano level inorganic salt, because huge surface energy, very easy gathering is agglomerating, thereby forms micron-sized magnesiumcarbonate.
" salt industry and chemical industry " impurity the 38th is rolled up the 21st~23 page of the 1st phase and has been introduced with MgCl
26H
2O is a raw material, adopts the method for precipitation from homogeneous solution synthesis of nano magnesium basic carbonate, and the concrete steps of this method are as follows:
With MgCl
26H
2O, CO (NH
2)
2Be reaction raw materials, it be made into the easy of desired concn, earlier with CO (NH
2)
2Add in the four-hole boiling flask, be heated to certain temperature, slowly add MgCl again
2Solution; Heating, stir, after reaction for some time, ageing 1h naturally lowers the temperature; Filtration under diminished pressure, being washed to no chlorion repeatedly detects, carry out solvent exchange 3 times with the 20ml absolute ethanol washing again, the magnesium basic carbonate that obtains be deposited in the loft drier 110 ℃ down dry 2h promptly obtain the magnesium basic carbonate powder, find that with this magnesium basic carbonate of electron microscopic observation its median size is 40nm.
This method is because CO (NH
2)
2Hydrolysis rate is very slow in heat-processed, and employing nature ageing, so crystallization time is longer, be unfavorable for large-scale industrial production, and because the surface energy of the nano-calcium carbonate magnesium crystal that crystallizes out is still very big, be easy to reunite, so, the productive rate of the nano-calcium carbonate magnesium that obtains by this method is not high, also has micron-sized magnesiumcarbonate in product.
[summary of the invention]
In order to solve above-mentioned technical problem, the nano-calcium carbonate magnesium crystal that the present invention proposes a kind of preparation method of new nano-calcium carbonate magnesium crystal and utilize this method preparation.It is fast that the preparation method that the present invention proposes prepares nano-calcium carbonate magnesium crystal speed, the nano-calcium carbonate magnesium crystal purity height of preparing.
Concrete technical scheme of the present invention is as follows:
The invention provides a kind of preparation method of nano-calcium carbonate magnesium crystal, it is characterized in that, this method comprises the steps:
(1) compound concentration is the MgCl of 0.4mol/l~2.2mol/l
2Solution;
(2) to the MgCl of every 100ml
2Drip the tensio-active agent of 0.01g-1g in the solution;
(3) compound concentration is the ammonia soln of 1.6mol/l~8.8mol/l;
(4) in above-mentioned ammonia soln, feed a certain amount of carbon dioxide, make NH
4 +With CO
2Mol ratio be 2: 1;
(5) in the ammoniacal liquor carbonic acid gas solution system of every 100ml, add the nano-oxide of 0.001g-0.1g, and slowly stir as nucleus;
(6) under 5 ℃~60 ℃, in the ammoniacal liquor carbonic acid gas solution that is added with nano-oxide, slowly drip a certain amount of MgCl that is added with tensio-active agent
2Solution is kept Mg at last
2+: NH
4 +: CO
2Mol ratio be 1: 4: 2, after dropwising, slowly stir after 2~5 minutes and left standstill 20~30 minutes, filtration under diminished pressure and with dehydrated alcohol repetitive scrubbing 2~4 times at 150 ℃~300 ℃ down dry 2~3h, obtains product at last then.
Described tensio-active agent is Macrogol 200 (PEG200), poly(oxyethylene glycol) 400 (PEG400) or alkylphenol polyoxyethylene (OP-10).
Described nano-oxide as nucleus is that mass percent is the nano-TiO of 0.5%-15%
2Colloidal sol, described nano-TiO
2The volume of colloidal sol is 0.2ml~120ml.
Described nano-oxide thing as nucleus is nano-MgO crystal grain or nanometer SiO
2Powder.
The described median size that is used as the nano-oxide of nucleus is 1~50nm.
The present invention also provides a kind of nano-calcium carbonate magnesium crystal, it is characterized in that, comprises also in this nano-calcium carbonate magnesium crystal that mass percent is 0.1%~10% nano-oxide nucleus.
Described nano-oxide nucleus is nano-MgO, nanometer SiO
2And nano-TiO
2In a kind of.
The median size of described nano-oxide nucleus is 1~50nm.
The median size of described nano-calcium carbonate magnesium crystal is 50~300nm.
The heat decomposition temperature of described nano-calcium carbonate magnesium crystal is 360~420 ℃.
Beneficial technical effects of the present invention is:
In the process of preparation nano-calcium carbonate magnesium crystal, add tensio-active agent, reduce the surface energy of nanocrystal, can effectively prevent the reunion of nanocrystal, make the nano-calcium carbonate magnesium crystal particle diameter that is worth diminish.
In the process of preparation nano-calcium carbonate magnesium crystal, add the nucleus that promotes crystal growth, can accelerate the formation of nanocrystal, saved the time, improved production efficiency.
The nano-oxide nucleus of nano-calcium carbonate magnesium crystal is a kind of nucleator that brings out crystal growth with low cost, not only can improve crystal formation speed, and nanocrystal is when being nano inorganic oxides such as silicon-dioxide or magnesium oxide or titanium dioxide, wrapped up by the nano-calcium carbonate magnesium crystal, not only the performance to the nano-calcium carbonate magnesium crystal can not exert an influence, play the purpose of engineering plastics being carried out modification but also can act synergistically with nano-calcium carbonate magnesium, improved the machinery of engineering plastics, mechanics and chemistry, physicals, even so inner nano-oxide that is enclosed with of the nano-calcium carbonate magnesium crystal that the present invention prepares, also need not purification step, saved production cost.
[Figure of description]
Fig. 1 is the thermogravimetic analysis (TGA) figure (TG) of embodiment 2 nano-calcium carbonate magnesium crystals;
Fig. 2 is the Electronic Speculum figure (SEM) of embodiment 3 nano-calcium carbonate magnesium crystals.
[embodiment]
The nano-calcium carbonate magnesium crystal that the present invention relates to a kind of preparation method of nano-calcium carbonate magnesium crystal and utilize this method preparation.
Below in conjunction with specific embodiment the present invention is done further detailed elaboration and explanation (preparation process of nano-calcium carbonate magnesium unless otherwise indicated is under the normal temperature and pressure and carries out among all embodiment):
Embodiment 1
A kind of nano-calcium carbonate magnesium crystal, the concrete steps that prepare this nano-calcium carbonate magnesium crystal are as follows:
(1) preparation 100ml, volumetric molar concentration are the MgCl of 0.4mol/l
2Solution;
(2) to the MgCl of 100ml
2Drip the Macrogol 200 (PEG200) of 0.1g in the solution as tensio-active agent;
(3) preparation 100ml, concentration are the ammonia soln of 1.6mol/l;
(4) in above-mentioned ammonia soln, feed an amount of carbon dioxide, make NH
4 +With CO
2Mol ratio be 2: 1;
(5) add the nano magnesia crystal grain of 0.04g as nucleus in above-mentioned ammoniacal liquor carbonic acid gas solution system, the median size of described nano magnesia is 50nm;
(6) under 5 ℃, in the ammoniacal liquor carbonic acid gas solution that is added with nano magnesia, slowly drip the MgCl that is added with Macrogol 200 that above-mentioned steps (2) makes
2Solution is kept Mg at last
2+: NH
4 +: CO
2Mol ratio be 1: 4: 2, after dropwising, stir and left standstill 30 minutes after 2 minutes, filtration under diminished pressure and with dehydrated alcohol repetitive scrubbing 2 times then at 150 ℃ of dry 2h down, obtains product at last.
The product that makes is the nano-calcium carbonate magnesium crystal, and the median size of nano-calcium carbonate magnesium crystal is 300nm.Comprise also in the described nano-calcium carbonate magnesium crystal that mass fraction is 1% nano magnesia nucleus, be wrapped in the inside of described nano-calcium carbonate magnesium crystal, the median size of described nano magnesia nucleus is 50nm.The heat decomposition temperature that records the nano-calcium carbonate magnesium crystal that makes by thermogravimetric analyzer is 420 ℃.
Embodiment 2
A kind of nano-calcium carbonate magnesium crystal, the concrete steps that prepare this nano-calcium carbonate magnesium crystal are as follows:
(1) preparation 100ml, volumetric molar concentration are the MgCl of 1.725mol/l
2Solution;
(2) to the MgCl of 100ml
2Drip the poly(oxyethylene glycol) 400 (PEG400) of 0.5g in the solution as tensio-active agent;
(3) preparation 100ml, concentration are the ammonia soln of 7mol/l;
(4) in above-mentioned ammonia soln, feed an amount of carbon dioxide, make NH
4 +With CO
2Mol ratio be 4: 2;
(5) add the nanometer titanium dioxide silicon crystal grain of 0.01g as nucleus in ammoniacal liquor carbonic acid gas solution system, the median size of described nano silicon is 20nm;
(6) under 25 ℃, in the ammoniacal liquor carbonic acid gas solution that is added with nano silicon, slowly drip the MgCl that is added with poly(oxyethylene glycol) 400 that above-mentioned steps (2) makes
2Solution is kept Mg at last
2+: NH
4 +: CO
2Mol ratio be 1: 4: 2, after dropwising, stir and left standstill 25 minutes after 3 minutes, filtration under diminished pressure and with dehydrated alcohol repetitive scrubbing 3 times then at 200 ℃ of dry 2h down, obtains product at last.
The product that makes is the nano-calcium carbonate magnesium crystal, and the median size of nano-calcium carbonate magnesium crystal is 100nm.Comprise also in the described nano-calcium carbonate magnesium crystal that mass fraction is 0.25% nano silicon nucleus, be wrapped in the inside of described nano-calcium carbonate magnesium crystal, the median size of described nano silicon nucleus is 20nm.The heat decomposition temperature that records the nano-calcium carbonate magnesium crystal that makes by thermogravimetric analyzer is 398 ℃, and the thermogravimetic analysis (TGA) of described nano-calcium carbonate magnesium (TG) is schemed as shown in Figure 1.
Embodiment 3
A kind of nano-calcium carbonate magnesium crystal, the concrete steps that prepare this nano-calcium carbonate magnesium crystal are as follows:
(1) preparation 100ml, volumetric molar concentration are the MgCl of 1.725mol/l
2Solution;
(2) to the MgCl of 100ml
2Drip the alkylphenol polyoxyethylene (OP-10) of 0.02mg in the solution as tensio-active agent;
(3) preparation 200ml, concentration are the ammonia soln of 3.5mol/l;
(4) in above-mentioned ammonia soln, feed an amount of carbon dioxide, make NH
4 +With CO
2Mol ratio be 4: 2;
(5) in ammoniacal liquor carbonic acid gas solution system, add 0.5ml, 8% as the nano-TiO of nucleus
2Colloidal sol slowly stirs, described nano-TiO
2The median size of colloidal sol is 8nm;
(6) under 60 ℃, to the above-mentioned nano-TiO that is added with
2The 100ml that slow dropping above-mentioned steps (2) makes in the ammoniacal liquor carbonic acid gas solution of colloidal sol is added with the MgCl of alkylphenol polyoxyethylene (OP-10)
2Solution is kept Mg at last
2+: NH
4 +: CO
2Mol ratio be 1: 4: 2, after dropwising, stir and left standstill 20 minutes after 5 minutes, filtration under diminished pressure and with dehydrated alcohol repetitive scrubbing 4 times then at 300 ℃ of dry 2h down, obtains product at last.
The product that makes is the nano-calcium carbonate magnesium crystal, and the median size of nano-calcium carbonate magnesium crystal is 200nm, and the Electronic Speculum figure of this nano-calcium carbonate magnesium (SEM) as shown in Figure 2.Comprise also in the described nano-calcium carbonate magnesium crystal that mass fraction is 1% nano TiO 2, be wrapped in the inside of described nano-calcium carbonate magnesium crystal, the median size of described nano TiO 2 nucleus is 8nm.
Embodiment 4
A kind of nano-calcium carbonate magnesium crystal, the concrete steps that prepare this nano-calcium carbonate magnesium crystal are as follows:
(1) preparation 100ml, volumetric molar concentration are the MgCl of 2.2mol/l
2Solution;
(2) to the MgCl of 100ml
2Drip the poly(oxyethylene glycol) 400 (PEG400) of 0.5mg in the solution as tensio-active agent;
(3) preparation 100ml, concentration are the ammonia soln of 8.8mol/l;
(4) in above-mentioned ammonia soln, feed an amount of carbon dioxide, make NH
4 +With CO
2Mol ratio be 4: 2;
(5) add the nano-calcium carbonate magnesium crystal grain of 0.01g as nucleus in ammoniacal liquor carbonic acid gas solution system, the median size of described nano-calcium carbonate magnesium crystal grain is 50nm;
(6) under 35 ℃, in the above-mentioned ammoniacal liquor carbonic acid gas solution that is added with nano-calcium carbonate magnesium crystal grain, slowly drip the MgCl that is added with poly(oxyethylene glycol) 400 that above-mentioned steps (2) makes
2Solution is kept Mg at last
2+: NH
4 +: CO
2Mol ratio be 1: 4: 2, after dropwising, slowly stir after 3 minutes and left standstill 25 minutes, filtration under diminished pressure and with dehydrated alcohol repetitive scrubbing 3 times then at 150 ℃ of dry 2h down, obtains product at last.
The product that makes is the nano-calcium carbonate magnesium crystal, and the median size of nano-calcium carbonate magnesium crystal is 50nm.The heat decomposition temperature that records the nano-calcium carbonate magnesium crystal that makes by thermogravimetric analyzer is 360 ℃.
Need to prove that those skilled in the art can also the very simple embodiment that expects other at the above embodiments, and, just can access some improvement by simply repeatedly experiment.But no matter how to improve,, belong to the protection domain of this patent as long as these technical schemes in design scope of the present invention, should be equal to the technical scheme of this patent.