1. A high-temperature dehydroxylation method is characterized in that the prepared silica gel raw material does not contain hydroxyl, and the method comprises the following steps: the method comprises the following steps:

1) selecting silica gel particles as raw materials, wherein the average particle size of the silica gel particles is 75-150 mu m,

2) a clean heat source (2) is arranged at the head end of the heating pipe (1);

3) the tail end of the heating pipe (1) is provided with a feeding air pipe (3) correspondingly penetrating through the heating pipe (1), and the tail end temperature of the heating pipe (1) is 700-;

4) one end of the feeding air pipe (3) is provided with a feeding and blowing device (4) for providing wind power and raw materials, and the other end of the feeding air pipe (3) is provided with a discharge recovery box (5);

5) the raw material passes through the heating pipe (1) through the feeding air pipe (3), hydroxyl in the raw material is removed by utilizing the high temperature at the tail end of the heat source (2), and the speed of the raw material passing through the peripheral area is 0.4-1.2 m/s;

6) and finally, the raw materials are recovered through a discharge recovery box (5).

2. The method of claim 1, wherein the silica gel is protected from yellowing by: the heating pipe (1) is a radio frequency plasma torch, and the heat source (2) is radio frequency plasma flame in the radio frequency plasma torch.

3. The method of claim 2, wherein the silica gel is protected from yellowing by: the power of the radio frequency plasma torch is 40-90 KW.

4. The method of claim 1, wherein the silica gel is protected from yellowing by: the feeding speed of the feeding air pipe (3) is 30-120 g/min.

5. The method of claim 1, wherein the silica gel is protected from yellowing by: feed blast apparatus (4) contain feed box (4.1), conveying pipe (4.3) and discharging pipe (4.5), feed box (4.1) are equipped with the feed inlet, air intake and discharge gate, and the feed inlet, air intake and discharge gate all are equipped with control valve (4.2), the feed inlet corresponds with head tank (6) through conveying pipe (4.3) and is connected, the air intake passes through blast pipe (4.4) and corresponds with fan (7) and is connected, the discharge gate passes through discharging pipe (4.5) and corresponds sealed intercommunication back with closing of heating pipe (1), provide raw materials and wind-force for the pay-off wind channel.

6. The method of claim 1, wherein the silica gel is protected from yellowing by: the pipe wall of heating pipe (1) runs through and is equipped with open slot (1.1), and the tail end of opening towards heating pipe (1) of open slot (1.1), this open slot (1.1) is passed in corresponding cooperation in pay-off tuber pipe (3), and the pay-off tuber pipe (3) shaft that is located heating pipe (1) is equipped with heating mouth (3.1).

7. The method of claim 6, wherein the silica gel is prevented from yellowing by: and the feeding air pipe (3) is correspondingly communicated with the discharging recovery box (5) through a corrugated hose.

8. The method of claim 1, wherein the silica gel is protected from yellowing by: the inner cavity of the discharge recycling box (5) is divided into an upper layer and a lower layer through a ventilation plate (5.1), the upper layer is used for collecting raw materials, and the lower layer is used for recycling and discharging gas.

9. The method of claim 8, wherein the silica gel is protected from yellowing by: the lower layer of the inner cavity of the discharge recycling box (5) is provided with at least one activated carbon filter layer.

10. The method of claim 8, wherein the silica gel is protected from yellowing by: the air permeable plate (5.1) is obliquely arranged, and a discharging channel (5.2) is arranged at the lower end of the discharging recovery box (5) corresponding to the air permeable plate (5.1).

Background

As is known, the current silica gel products are more and more widely used, and common silica gel products can be divided into molded silica gel products, extruded silica gel products and liquid silica gel products according to different molding processes; the molded silica gel product is mainly used for manufacturing products such as silica gel industrial accessories, molds, baby nipples and the like, but after the silica gel product is exposed in the air, hydroxyl in the silica gel product is subjected to oxidation reaction, and the surface of the silica gel product is yellowed after a long time, so that the attractiveness and the use safety of the silica gel product are affected, for example, the transparency of the silica gel mobile phone shell is reduced after the silica gel mobile phone shell is yellowed, and the attractiveness, the hardness, the service life and the like of the mobile phone shell are affected; after the silica gel nipple turns yellow, children may absorb some oxidized molecules when using the nipple, so that adverse effects are caused;

the traditional method for solving the problem of yellowing of the silica gel product is that the silica gel product is directly discarded after the silica gel product is yellowed, so that the method causes waste of the silica gel product and increases the workload of a waste degradation industry; the other method is that a vulcanizing agent with yellowing resistance is added into the silica gel raw material when the silica gel product is produced, although the method can prevent the silica gel product from yellowing to a certain extent, the silica gel product produced by the method contains sulfide, and if the silica gel product is used for producing articles such as nipples and the like which need to be contacted with a human body, the silica gel product may cause harm to the human body; therefore, in summary, there is a need in the market for a method capable of effectively solving the problem of yellowing of silica gel products and ensuring the safety performance of the silica gel products in use.

Disclosure of Invention

In order to overcome the defects in the background art, the invention discloses a high-temperature dehydroxylation method.

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

a high temperature dehydroxylation process for producing a silica gel feedstock free of hydroxyl groups, said process comprising the steps of

1) Selecting silica gel particles as raw materials, wherein the average particle size of the silica gel particles is 75-150 mu m,

2) arranging a clean heat source at the head end of the heating pipe;

3) the tail end of the heating pipe is provided with a feeding air pipe which is vertically communicated with the heating pipe correspondingly, and the temperature of the tail end of the heating pipe is 700-900 ℃;

4) the tail end of the heating pipe is provided with a discharge recovery box corresponding to the feeding air pipe;

5) the raw material passes through the heating pipe through the feeding air pipe, hydroxyl in the raw material is removed by utilizing the high temperature at the tail end of the heat source, and the speed of the raw material passing through the peripheral area is 0.4-1.2 m/s;

6) and finally, recovering the raw materials through a discharge recovery box.

Preferably, the heating pipe is a radio frequency plasma torch, and the heat source is a radio frequency plasma flame in the radio frequency plasma torch;

preferably, the power of the radio frequency plasma torch is 40-90 KW;

preferably, the feeding speed of the feeding air pipe is 30-120 g/min;

preferably, the feeding and blowing device comprises a feeding box, a feeding pipe and a discharging pipe, the feeding box is provided with a feeding port, an air inlet and a discharging port, the feeding port, the air inlet and the discharging port are respectively provided with a control valve, the feeding port is correspondingly connected with the raw material tank through the feeding pipe, the air inlet is correspondingly connected with the fan through the air supply pipe, and the discharging port is correspondingly sealed and communicated with the heating pipe through the discharging pipe to provide raw materials and wind power for the feeding air channel;

preferably, the pipe wall of the heating pipe is provided with an open slot in a penetrating manner, the opening of the open slot faces the tail end of the heating pipe, the feeding air pipe correspondingly penetrates through the open slot in a matching manner, and the pipe body of the feeding air pipe positioned in the heating pipe is provided with a heating opening;

preferably, the feeding air pipe is correspondingly communicated with the discharging recovery box through a corrugated hose;

preferably, the inner cavity of the discharge recovery box is divided into an upper layer and a lower layer by a ventilation plate, the upper layer is used for collecting raw materials, and the lower layer is used for recovering and discharging gas;

preferably, at least one activated carbon filter layer is arranged on the lower layer of the inner cavity of the discharge recovery box;

preferably, the ventilation plate is obliquely arranged, and a discharging channel is arranged at the lower end of the discharging recovery box corresponding to the ventilation plate.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

according to the high-temperature dehydroxylation method disclosed by the invention, the raw materials can be driven by the feeding air pipe to rapidly pass through the heating pipe, and the hydroxyl in the raw materials is removed by utilizing the residual heat of the heat source at the tail end of the heating pipe, so that a silica gel product prepared by utilizing the raw materials cannot be yellowed; in addition, the feeding air blowing device can provide wind power and raw materials for the feeding air channel at the same time, and the discharging recovery box can collect the raw materials and discharge redundant gas.

Drawings

FIG. 1 is a schematic structural view of the present invention;

fig. 2 is a schematic structural view of a heating pipe open slot.

In the figure: 1. heating a tube; 1.1, opening grooves; 2. a heat source; 3. a feeding air pipe; 3.1, opening; 4. a feeding and blowing device; 4.1, a feeding box; 4.2, a control valve; 4.3, a feeding pipe; 4.4, an air supply pipe; 4.5, a discharge pipe; 5. a discharge recycling bin; 5.1, ventilating plates; 5.2, a discharge channel; 6. a raw material tank; 7. a fan.

Detailed Description

The present invention will be explained in detail by the following examples, which are disclosed for the purpose of protecting all technical improvements within the scope of the present invention.

The first embodiment of the method for preparing a silica gel raw material without hydroxyl groups by combining the high-temperature dehydroxylation method shown in the attached drawings 1-2 is as follows:

selecting silica gel particles with the particle size of 75 micrometers as a raw material, enabling the raw material to pass through a heating pipe 1 through a feeding air pipe 3, removing hydroxyl in the raw material by utilizing the residual temperature of a 700-DEG C heat source 2 at the tail end of the heating pipe 1, and enabling the speed of the raw material passing through the heating pipe 1 to be 0.3 m/s;

the second embodiment is as follows:

selecting silica gel particles of 150 microns as a raw material, then enabling the raw material to pass through a heating pipe 1 through a feeding air pipe 3, removing hydroxyl in the raw material by utilizing the residual temperature of a 900-DEG C heat source 2 at the tail end of the heating pipe 1, wherein the speed of the raw material passing through the heating pipe 1 is 1.2 m/s;

the third embodiment is as follows:

selecting 100 mu m silica gel particles as a raw material, then enabling the raw material to pass through a heating pipe 1 through a feeding air pipe 3, removing hydroxyl in the raw material by utilizing the residual temperature of a 800 ℃ heat source 2 at the tail end of the heating pipe 1, wherein the speed of the raw material passing through the heating pipe 1 is 0.7 m/s;

in addition, the heating pipe 1 is a radio frequency plasma torch, and the heat source 2 is radio frequency plasma flame in the radio frequency plasma torch, so that the purity of the heat source 2 is high, impurities are not contained, and the hydroxyl group removing operation of silica gel particles is smoother; in addition, one mode of adjusting the heating temperature of the raw material is as follows: according to the size of the raw material and the different speed of the raw material passing through the radio frequency plasma torch, the output power of the radio frequency plasma torch can be correspondingly adjusted, and finally the temperature at the tail end of the radio frequency plasma torch is ensured to be just right capable of carrying out hydroxyl removal operation on the passing silica gel particles without damaging the structure of the silica gel particles; one way of adjusting the heating temperature of the raw material is as follows: the tube wall of the heating tube 1 is provided with an open slot 1.1 in a penetrating manner, the opening of the open slot 1.1 faces the tail end of the heating tube 1, the feeding air pipe 3 correspondingly penetrates through the open slot 1.1 in a matching manner, the feeding air pipe 3 can move up and down along the open slot 1.1 through the open slot 1.1, so that the distance between the feeding air pipe 3 and the heat source 2 is adjusted, the temperature of the raw material in the feeding air pipe 3 is controlled, and finally the temperature of the tail end of the radio frequency plasma torch is ensured to be right for carrying out hydroxyl removal operation on the passing silica gel particles, and the tube body of the feeding air pipe 3 in the heating tube 1 is provided with a heating port 3.1, so that the raw material can be directly heated by the residual heat of the heat source 2 to remove hydroxyl through the heating port 3.1 when the raw material is conveyed in the heating tube 1;

according to the requirement, the part of the feeding air pipe 3, which is positioned in the heating pipe 1, is correspondingly matched with the inner cavity of the heating pipe 1, and a sealing structure is arranged between the feeding air pipe 3 and the pipe wall of the heating pipe 1, so that the sealing performance between the heating pipe 1 and the feeding pipe 4.3 is ensured, and the raw material is prevented from leaking; in addition, the feeding speed in the feeding air pipe 3 is 30-120g/min, and when the feeding speed is lower, the feeding speed is reduced, so that the silica gel particles can be uniformly heated under various conditions;

according to the requirement, the feeding and blowing device 4 comprises a feeding box 4.1, a feeding pipe 4.3 and a discharging pipe 4.5, the feeding box 4.1 is provided with a feeding port, an air inlet and a discharging port, the feeding port, the air inlet and the discharging port are respectively provided with a control valve 4.2, the feeding port is correspondingly connected with a raw material tank 6 through the feeding pipe 4.3, the air inlet is correspondingly connected with a fan 7 through an air supply pipe 4.4, and the discharging port is correspondingly sealed and communicated with the heating pipe 1 through the discharging pipe 4.5, so that raw materials and wind power are provided for a feeding air pipe 3; when the feeding and blowing device 4 is used, firstly, the air inlet and the material outlet are closed, only the material inlet is opened to charge materials into the box body, after the materials are full, the material inlet is closed and the air inlet is opened, wind power is introduced into the box body through the fan 7, the materials in the box body are disordered, the situation that the materials are excessively accumulated at the material outlet and are blocked at the material outlet is prevented, and when the air pressure in the box body reaches the material outlet air pressure, the material outlet is opened, so that the materials are blown to the feeding air pipe 3 along with argon at a certain material outlet speed and material outlet speed; particularly, the pressure in the box body can be detected by arranging a pressure gauge on the feeding box 4.1;

according to the requirement, the inner cavity of the discharge recycling box 5 is divided into an upper layer and a lower layer by a ventilating plate 5.1, wherein the upper layer is used for collecting raw materials, and the lower layer is used for recycling and discharging gas; although silica gel granule can not produce impurity or harmful gas after the process high temperature, can thoughtlessly have unnecessary impurity when the silica gel granule is feeding, thereby can carry impurity in the raw materials behind the peripheral zone, and the lower floor of ejection of compact collection box 5 can be retrieved and discharge impurity, it is special, utilize the active carbon filter layer can all filter gaseous state or solid-state impurity, in addition, the ventilative board 5.1 of slope then can let the raw materials enter into discharging channel 5.2 automatically, in addition, pay-off tuber pipe 3 corresponds the intercommunication through corrugated hose and ejection of compact collection box 5, can not cause the influence to ejection of compact collection box 5 when making pay-off tuber pipe 3 reciprocate.

The present invention is not described in detail in the prior art.