CN115806745A

CN115806745A - Composite nano transparent iron oxide red and preparation method thereof

Info

Publication number: CN115806745A
Application number: CN202211467028.7A
Authority: CN
Inventors: 方畅; 方利浮; 方思博
Original assignee: Yunfu Hongzhi New Material Co ltd
Current assignee: Yunfu Hongzhi New Material Co ltd
Priority date: 2022-11-22
Filing date: 2022-11-22
Publication date: 2023-03-17
Anticipated expiration: 2042-11-22
Also published as: CN115806745B

Abstract

The invention discloses a composite nano transparent iron oxide red and a preparation method thereof. The preparation method of the composite nano transparent iron oxide red comprises the following steps: mixing the ferrous sulfate solution with the high-purity barium carbonate solution, grinding by using a nano sand mill, and reacting barium carbonate and ferrous sulfate to form ferrous carbonate, ferrous hydroxide and barium sulfate under the condition of high-energy collision refining of the nano sand mill; after the grinding reaction is finished, the grinding is changed into slow grinding, then air is introduced to oxidize ferrous hydroxide into ferric oxide, and the nano ferric oxide forms a compact coating layer on the surface of the nano barium sulfate; and then carrying out hydro-thermal treatment by using a hydro-thermal reaction kettle, and drying at low temperature to obtain the composite nano transparent iron oxide red. The method of the invention basically generates no by-products and pollutants, reduces the synthesis cost and solves the problem of the destination of the titanium dioxide by-product ferrous sulfate.

Description

Composite nano transparent iron oxide red and preparation method thereof

Technical Field

The invention relates to a preparation method of an inorganic pigment, in particular to a composite nano transparent iron oxide red and a preparation method thereof.

Background

The basic chemical expression of iron oxide is Fe ₂ O ₃ There are many different forms of a-type iron oxide, and the different forms of iron oxide exhibit different colors. Iron oxide is nontoxic, inexpensive, and an important base material having excellent properties in various fields such as building materials, paints, and rubbers. When the granularity of the iron oxide reaches the level of nanometer level, the specific surface area, the surface energy and the like are obviously increased along with the reduction of the particle size, the small-size effect is highlighted, the multi-scattering capability and the surface covering power of visible light waves are reduced, and a transparent state is presented, and meanwhile, a plurality of potential physical and chemical properties can be fully exerted, so that the transparent iron oxide can be widely applied in more fields.

The prior transparent iron oxide red has the problems of complex synthesis method, wide distribution of synthesized particle size, difficult dispersion and the like. For example, the Chinese patent application 'nano transparent iron oxide red' with the publication number of CN102603010A discloses a preparation method thereof: 1) Removing impurities, purifying and refining ferrous sulfate; 2) Preparing and oxidizing transparent iron oxide yellow seed crystals; 3) Preparing a transparent iron oxide red product. The invention takes ferrous sulfate as raw material and sodium carbonate as precipitator, firstly, ferrous carbonate precipitate is prepared, then air is introduced and composite additive is added, the ferrous carbonate is oxidized into transparent iron yellow, and the transparent iron red is prepared by calcining the iron yellow at the calcining temperature of 300-500 ℃. The transparent pigment particles prepared by the method are in a rice grain shape or approximate spindle shape, and the particle size of the product is controlled between 10 and 50 nanometers. However, the method is prepared by reacting sodium carbonate with ferrous sulfate and roasting, the process has high cost due to large sodium carbonate consumption, complicated roasting equipment, complex process, unstable product quality and serious pollution of sodium sulfate waste liquid generated in the process of filtering and rinsing.

Disclosure of Invention

In view of the above, the invention provides a method for preparing composite nano transparent iron oxide red, aiming at the problems of high cost, complex process and the like caused by large consumption of raw materials for preparing transparent iron oxide red in the prior art, in the method, the composite iron oxide red is prepared by separating and purifying ferrous sulfate as a titanium dioxide byproduct, mixing the separated and purified ferrous sulfate with high-purity barium carbonate, grinding the mixture by a sand mill, adopting a solid-liquid phase reaction, and generating a reaction under the condition of high-energy collision refining of the grinder. The invention is based on the improvement of raw materials and a reaction method, and is combined with a hydrothermal mode, so that the product grain diameter is more concentrated than that obtained by the traditional method, and the problem of difficult grain diameter increase and dispersion after sintering is solved.

In order to solve the technical problems, the invention adopts the following technical scheme:

a manufacturing method of composite nano transparent iron oxide red comprises the following steps:

mixing the ferrous sulfate solution with the high-purity barium carbonate solution, grinding by using a nano sand mill, and reacting barium carbonate and ferrous sulfate to form ferrous compounds (ferrous carbonate and ferrous hydroxide) and barium sulfate under the condition of high-energy collision refining of the nano sand mill; the rotation speed of the nano sand mill at this stage is 2900r/min, and the grinding time is 180-360min;

after the grinding reaction is finished, the speed is reduced to continue slow grinding (the speed is only needed to achieve the stirring effect, the speed is not needed to be required specifically, and preparation is made for subsequent oxidation), air/oxygen is introduced during the slow grinding to oxidize ferrous hydroxide and ferrous carbonate into nano ferric oxide with crystal water finally, the formed nano ferric oxide is attached to the surface of the nano barium sulfate, and the nano ferric oxide can form a compact coating layer on the surface of the nano barium sulfate; in the invention, the temperature of the grinding slurry is kept between 20 and 40 ℃ during the whole grinding period. And the slow grinding time is 100min-120min, preferably, the slow grinding speed is as follows: 600-1000r/min. The air/oxygen introduction rate is 2-6L/min.

Then removing crystal water after hydrothermal treatment at 250-300 ℃ by using a hydrothermal reaction kettle, and dehydrating and drying to obtain the composite nano transparent iron oxide red. The effect of hydrothermal temperature on particle size is that the particles are coarser with higher temperature.

The structure of the composite nano transparent iron oxide red prepared by the invention is a core-shell structure, nano ferric oxide is taken as a shell, and nano barium sulfate is taken as a core. The nano-scale ferric oxide and barium sulfate particles have larger specific surface area, so that the nano-scale ferric oxide and barium sulfate particles can be mutually adsorbed; the particle size of the ferric oxide is smaller, so that the nano ferric oxide forms a compact coating layer on the surface of the barium sulfate particles.

Furthermore, in order to facilitate downstream application of the composite nano transparent iron oxide red, the composite nano transparent iron oxide red is subjected to surface modification, and the purpose of modification is to achieve good affinity with a high molecular polymer. The modified object is mainly ferric oxide on the outer surface layer. The surface modifier includes at least one of lauric acid, stearic acid, stearate, sodium dodecylbenzenesulfonate, sodium dodecylsulfate, silane, silicone, and the like.

The modification method comprises the following steps: adding water into the composite nano transparent iron oxide red for repulping, and heating to 60-70 ℃;

coating and modifying stearate, namely adding the stearate according to 0.2-0.5wt% of the composite nano transparent iron oxide red, and directly adding and stirring;

silane is coated and modified, after the pH value is regulated to 4-5, silane is added according to 2-3wt% of the composite nano transparent iron oxide red;

other silicone modifications such as dimethyl silicone oil, etc. can be made by dry coating, high mixing, and milling with honeycomb mill.

In addition, in the invention, a catalyst can be added into the nano-grinder, the catalyst is preferably oxalic acid, the oxalic acid can be decomposed after being calcined without residue, and the decomposition is started at 190 ℃.

Compared with the prior art, the invention has the beneficial effects that:

the invention reacts under grinding: barium carbonate + ferrous sulfate = barium sulfate + ferrous carbonate + ferrous hydroxide, and air/oxygen is introduced to oxidize the ferrous iron to form ferric oxide. Ferric oxide is attached to the surface of barium sulfate to form a compound.

The invention solves the problem of the destination of ferrous sulfate as a byproduct of titanium dioxide, and has the characteristics of easy production, low raw material price, environment-friendly production, no byproduct, no environmental pollution and the like. The product has low surface energy after hydrothermal treatment and is easy to disperse, and the compound takes nano barium sulfate as a core to form transparent iron oxide red; after organic modification, the modified polymer has good affinity with high molecular polymers, is easy to disperse even if not modified, and can resist high temperature without color change. The organic substance is decomposed at high temperature after modification, and the use temperature is generally below 300 ℃. The product has good stability, barium sulfate and ferric oxide are not easy to agglomerate under the compounding condition, and the barium sulfate can prevent the ferric oxide from agglomerating with each other.

Drawings

FIG. 1 is an SEM photograph of the product of example 1.

FIG. 2 is an SEM photograph of the product of example 2.

FIG. 3 is an SEM image of the product of example 3.

FIG. 4 is an SEM photograph of the product of example 4.

FIG. 5 is a spectral reflectance plot of examples 1-4 and a comparative example;

FIG. 6 is an external view of the product of example 1.

Detailed Description

In order to make the present invention more clear and intuitive for those skilled in the art, the present invention will be further described with reference to the accompanying drawings.

Example 1

Mixing 1L of 1mol/L ferrous sulfate solution with 1L of 1mol/L industrial barium carbonate, dispersing uniformly by using a high-speed stirrer, pumping into an experimental nano sand mill through a diaphragm pump, increasing the rotating speed to 2900r/min, grinding for 180min, and grinding at a low speed after the reaction is finished, wherein the low-speed grinding speed is as follows: 600r/min, and the slow grinding time is 120min; starting to introduce air during the slow grinding period, wherein the air introduction rate is 6L/min; the temperature of the grinding slurry is kept between 20 and 40 ℃ during the whole grinding period. After the slurry is discharged, the ground slurry is placed in a hydrothermal reaction kettle for hydrothermal reaction at 250 ℃ for 2 hours, after drying, the obtained paste is added with water to be repulped into 10-15wt% of paste, heated to 60-70 ℃, added with sodium stearate with the mass of 0.2-0.5wt% of the composite nano transparent iron oxide red, kept warm and stirred for 30min, dehydrated and dried at 90 ℃. The finished product is detected for particle size and scanning by an electron microscope, and the hue and dispersion of the composite nano transparent iron red in the example 1 are detected.

Example 2

Mixing 1L of 1mol/L ferrous sulfate solution with 1L of 1mol/L industrial barium carbonate, dispersing uniformly by using a high-speed stirrer, pumping into an experimental nano sand mill through a diaphragm pump, increasing the rotating speed to 2900r/min, grinding for 200min, and grinding at a low speed after the reaction is finished, wherein the low-speed grinding speed is as follows: 800r/min, and the slow grinding time is 110min; starting to introduce air during the slow grinding period, wherein the air introduction rate is 6L/min; the temperature of the grinding slurry is kept between 20 and 40 ℃ during the whole grinding period. After the slurry is discharged, the ground slurry is placed in a hydrothermal reaction kettle for hydrothermal reaction at 260 ℃ for 2h, the paste obtained after drying is added with water and repulped into a paste with the mass number of 10-15wt%, the paste is heated to 60-70 ℃, then sodium stearate with the mass of 0.2-0.5wt% of the composite nano transparent iron oxide red is added, the mixture is stirred for 30min under heat preservation, dehydrated and dried at 105 ℃. The finished product is detected for particle size and scanned by an electron microscope, and the hue and dispersion of the composite nano transparent iron oxide red in the example 2 are detected.

Example 3

Mixing 1L of 1mol/L ferrous sulfate solution with 1L of 1mol/L industrial barium carbonate, dispersing uniformly by using a high-speed stirrer, pumping into an experimental nano sand mill through a diaphragm pump, increasing the rotating speed to 2900r/min, grinding for 240min, and grinding at a low speed after the reaction is finished, wherein the low-speed grinding speed is as follows: 900r/min, and the slow grinding time is 105min; starting to introduce air during the slow grinding period, wherein the air introduction rate is 6L/min; the temperature of the grinding slurry is kept between 20 and 40 ℃ during grinding. After the slurry is discharged, the ground slurry is placed in a hydrothermal reaction kettle at 280 ℃ for hydrothermal reaction for 2 hours, the paste obtained after drying is added with water and repulped into the paste with the mass number of 10-15wt%, the paste is heated to 60-70 ℃, then sodium stearate with the mass of 0.2-0.5wt% of the composite nano transparent iron oxide red is added, the mixture is stirred for 30 minutes under heat preservation, dehydrated and dried at 105 ℃. The finished product is detected for particle size and scanned by an electron microscope, and the hue and dispersion of the composite nano transparent iron oxide red in the example 3 are detected.

Example 4

1L of 1mol/L ferrous sulfate solution is mixed with 1L of 1mol/L industrial barium carbonate, the mixture is uniformly dispersed by a high-speed stirrer and then is pumped into an experimental nano sand mill through a diaphragm pump, the rotating speed is increased to 2900r/min for grinding for 360min, and slow grinding is carried out after the reaction is finished, wherein the slow grinding speed is as follows: 1000r/min, and the slow grinding time is 100min; starting to introduce air during the slow grinding period, wherein the air introduction speed is 6L/min; the temperature of the grinding slurry is kept between 20 and 40 ℃ during grinding. After the slurry is discharged, the ground slurry is placed in a hydrothermal reaction kettle at 300 ℃ for hydrothermal reaction for 2 hours, the paste obtained after drying is added with water and repulped into a paste with the mass number of 10-15wt%, the paste is heated to 60-70 ℃, then sodium stearate with the mass of 0.2-0.5wt% of the composite nano transparent iron oxide red is added, the mixture is stirred for 30 minutes under heat preservation, dehydrated and dried at 105 ℃. The grain size of the finished product is detected, the finished product is scanned by an electron microscope, and the hue and the dispersion of the composite nano transparent iron oxide red in the example 4 are detected.

The electron microscope scanning images of the above 4 examples are shown in fig. 1-4, respectively, and in fig. 1-4, it can be seen that dense rugged small particles exist on the surface of the large sphere, which can prove that the products obtained in examples 1-4 are composite core-shell structures.

The properties of each example and comparative example are shown in table 1.

TABLE 1

Description of the drawings:

l: the brightness of the color is indicated, positive numbers indicate white bias, and negative numbers indicate black bias. a: indicating a reddish green value, positive numbers indicating a reddish bias, and negative numbers indicating a greenish bias. b: indicating a yellow-blue value.

The comparative example was red Cheng Touming iron oxide.

Table 1 shows that the higher the hydrothermal temperature, the higher the conversion rate of the product, the better the dispersibility, but the larger the particle size. In addition, the data obtained by the test shows that the hue L value of the iron oxide red is improved, the brightness is better, and the red phase is slightly inferior to that of the pure iron oxide red of the comparative example.

The spectral plot shown in FIG. 5 provides a more intuitive comparison of the results of the examples and comparative examples, with the red spectral reflectance being predominantly between 600-740nm, compared to the comparative spectrum, which is higher for the examples at 600-740nm, demonstrating the higher color shade and brightness of the examples compared to the comparative example.

In conclusion, compared with the transparent iron oxide red obtained by the traditional method, the iron oxide red synthesized by the method has smaller particle size, higher transparency and lower cost.

Fig. 6 is an appearance diagram of a product of iron oxide red obtained as typified by example 1, which is seen as bright red from the original figure.

The embodiments described above are presented to enable those skilled in the art to make and use the invention. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the embodiments described herein, and those skilled in the art should make improvements and modifications to the present invention based on the disclosure of the present invention within the protection scope of the present invention.

Claims

1. The preparation method of the composite nano transparent iron oxide red is characterized by comprising the following steps:

mixing the ferrous sulfate solution with the high-purity barium carbonate solution, grinding by using a nano sand mill, and reacting barium carbonate with ferrous sulfate to form ferrous carbonate, ferrous hydroxide and barium sulfate under the condition of high-energy collision refinement of the nano sand mill;

after the grinding reaction is finished, the grinding is converted into slow grinding, air/oxygen is introduced during the slow grinding to oxidize ferrous hydroxide and ferrous carbonate into nano ferric oxide with crystal water, and the nano ferric oxide forms a compact coating layer on the surface of the nano barium sulfate;

then carrying out hydro-thermal treatment by using a hydro-thermal reaction kettle, and dehydrating and drying to obtain the composite nano transparent iron oxide red.

2. The method of claim 1, wherein the temperature of the slurry is maintained at 20-40 ℃ throughout the milling period.

3. The method for preparing composite nano transparent iron oxide red according to claim 1, wherein the slow grinding speed is as follows: 600-1000r/min, and the slow grinding time is 100-120 min.

4. The method for preparing composite nano transparent iron oxide red according to claim 1, wherein the air/oxygen gas introduction rate is 2-6L/min.

5. The method of claim 1, wherein the initial polishing rate is 2900r/min, and the polishing is maintained for 180-360min.

6. The method according to claim 1, wherein the transparent iron oxide red is further surface-modified by a surface modifier.

7. The method of claim 6, wherein the surface modifier comprises at least one of lauric acid, stearic acid, stearate, sodium dodecylbenzene sulfonate, sodium dodecylsulfate, silane, and silicone.

8. The method for preparing composite nano transparent iron oxide red according to claim 1, wherein the temperature of the hydrothermal reaction kettle is 250-300 ℃.

9. The method for preparing composite nano transparent iron oxide red according to claim 1, wherein the ferrous sulfate is ferrous sulfate as a byproduct of titanium dioxide.

10. The composite nano transparent iron oxide red prepared by the method for preparing the composite nano transparent iron oxide red according to any one of claims 1 to 9.