A lithium silicate microcrystalline product and preparation method thereof

Abstract

The present invention provides a lithium silicate microcrystalline product, which is composed of the following weight components: 5%-7.8% lithium silicate and 92.2%-95% silicon dioxide. And a preparation method thereof, comprising the following steps: step 1: weighing lithium silicate and silicon dioxide according to a ratio and mixing; step 2: sintering the mixture into a product embryo; step 3: gradually heating the product embryo to 730℃-745℃, and keeping the constant temperature for 25-35 minutes, then quickly heating to 952℃-955℃, and keeping it for 8-15 minutes, then cooling it down, and then transferring it to an annealing furnace, and naturally cooling it to room temperature after annealing to obtain a microcrystalline product. The present invention only uses two raw materials, lithium silicate and silicon dioxide, and has a high microcrystalline conversion rate. The prepared microcrystalline product has good hardness, is easy to clean, resistant to bumps, mildew-proof, and not easy to hide dirt.

Description

Technical Field

[0001] The invention belongs to the technical field of microcrystal preparation, and particularly relates to a lithium silicate microcrystal product and a preparation method thereof. Background Art

[0002] Glass-ceramics refers to a basic glass of a specific composition with or without a crystal nucleating agent. When subjected to a crystallization heat treatment under a certain temperature regime, a large number of tiny crystals are uniformly precipitated in the glass, forming a dense multiphase complex of microcrystalline phase and glass phase. Because of its good corrosion resistance, wear resistance and safety, it is often used as tableware, such as chopsticks, plates, teacups, etc.

[0003] Wooden and bamboo chopsticks have loose structures. After long-term use, many tiny grooves will appear on the surface, which are very easy to retain bacteria. In a humid storage environment, wooden chopsticks are prone to bacteria and mold, which can enter the human body with food and endanger human health. Chopsticks made of microcrystalline glass have become the most common substitute for wooden and bamboo chopsticks. For example, the invention of application publication number CN113185130A discloses a kind of drop-resistant microcrystalline glass ceramic chopsticks and its preparation method, the chopsticks contain the following components: 55-70% quartz sand, 15-25% lithium carbonate, 5-10% aluminum oxide, 3-10% potassium nitrate, 0.1-1% silver nitrate, 0.1-1% cerium oxide; A, ingredients: weigh all raw materials according to the proportion of the corresponding weight; B, mixing: put the raw materials into a fast mixer and mix for 30 minutes; C, melt, keep warm at 1550-1580℃ for 5 hours; D, discharge and shape; E, annealing; F, grinding and polishing; G, UV photosensitization; H, microcrystallization. However, the excessive number of components increases the difficulty of microcrystal transformation, so that the product still needs to be improved in terms of hardness and anti-fouling performance. Summary of the invention

[0004] The present invention aims at the technical problems existing in the prior art and provides a lithium silicate microcrystalline product and a preparation method thereof. Only two raw materials, lithium silicate and silicon dioxide, are used, and the microcrystalline conversion rate is high. The prepared microcrystalline product has good hardness, is easy to clean, is resistant to knocks and mildew, and is not easy to harbor dirt.

[0005] The technical solution adopted by the present invention is: a lithium silicate microcrystalline product, which is composed of the following components by weight: 5%-7.8% of lithium silicate and 92.2%-95% of silicon dioxide.

[0006] The technical solution adopted by the present invention is: the preparation method of the above-mentioned lithium silicate microcrystalline product comprises the following steps:

[0007] Step 1: Weigh lithium silicate and silicon dioxide according to the ratio and mix them;

[0008] Step 2: sintering the mixture into a finished product embryo;

[0009] Step 3: gradually heat the product embryo to 730℃-745℃, and keep the constant temperature for 25-35 minutes, then quickly heat it to 952℃-955℃, and keep it for 8-15 minutes, then cool it to 580℃-630℃, and then transfer it to the annealing furnace, keep it at 530℃-570℃ for 1.8-2.3 hours, then stop heating, and naturally cool it to room temperature to obtain a microcrystalline product.

[0010] Furthermore, in step 3, the constant temperature is maintained for 30 minutes.

[0011] Furthermore, in step 3, the temperature is rapidly raised to 953° C. and maintained for 10 minutes.

[0012] Furthermore, in step 2, the mixture is heated to 1500°C-1550°C and maintained for 0.8-1.5 hours; then poured into a mold and cooled to 580°C-630°C; after being taken out of the mold, it is placed in an annealing furnace and maintained at 530°C-570°C for 3.5-4.5 hours, and then the heating is stopped, and the mixture is naturally cooled to room temperature before being taken out of the furnace to obtain a product embryo.

[0013] Compared with the prior art, the present invention has the following beneficial effects: the raw materials of the present invention are only lithium silicate and silicon dioxide, and the most suitable microcrystalline transformation point temperature range is determined accordingly: 730°C-745°C, and after heating for 25-35 minutes, a cubic crystal structure similar to diamond is formed inside the fired product, and then the arrangement order of the microcrystalline molecules is basically fixed after heating to the microcrystalline fixed point: 953°C and maintaining for 8-15 minutes. The microcrystalline conversion rate of the lithium silicate microcrystalline product of the present invention reaches more than 95%, the hardness reaches 8.8, and it has the advantages of being easy to clean, resistant to knocks, mildew-proof, and not easy to harbor dirt. DETAILED DESCRIPTION

[0014] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with specific embodiments.

[0015] Example 1

[0016] An embodiment of the present invention provides a method for preparing a lithium silicate microcrystalline product, which comprises the following steps:

[0017] Step 1: Weigh 6.5 g of lithium silicate and 93.5 g of silicon dioxide, and mix them to obtain a mixture.

[0018] Step 2: Heat the mixture to 1500°C and keep it for 1 hour to make the mixture completely molten; then pour it into the chopstick mold and cool it to 600°C; after taking it out of the chopstick mold, put it into the annealing furnace and keep it at 550°C for 4 hours, then stop heating, cool it naturally to room temperature and then take it out of the furnace to obtain the finished product embryo.

[0019] Step 3: Place the product embryo in the furnace and gradually heat it to 738℃, and keep it at a constant temperature for 30 minutes, then quickly heat it to 953℃ and keep it for 10 minutes, then cool it down to 600℃, and then transfer it to the annealing furnace at 550℃ for 2 hours, then stop heating, and naturally cool it to room temperature to obtain microcrystalline chopsticks. The microcrystalline chopsticks are approximately cylindrical, with a length of 25 cm, a large end diameter of about 7 mm, and a small end diameter of about 5 mm.

[0020] Example 2

[0021] The embodiment of the present invention provides a method for preparing a lithium silicate microcrystalline product. The difference between this embodiment and embodiment 1 is that in step 3, the product embryo is placed in a furnace and gradually heated to 730° C. and maintained at a constant temperature for 30 minutes.

[0022] Example 3

[0023] The embodiment of the present invention provides a method for preparing a lithium silicate microcrystalline product. The difference between this embodiment and embodiment 1 is that in step 3, the product embryo is placed in a furnace and gradually heated to 745° C. and maintained at a constant temperature for 30 minutes.

[0024] Comparative Example 1

[0025] The difference between the comparative example of the present invention and Example 1 is that in step 3, the product embryo is placed in a furnace and gradually heated to 600° C., and the temperature is maintained at a constant temperature for 30 minutes.

[0026] Drop test 1

[0027] The microcrystalline chopsticks of Examples 1-3 and Comparative Example 1 were dropped from a height of 150 cm onto a cement floor, and the test was conducted 10,000 times respectively. The test results are as follows: 56 microcrystalline chopsticks of Example 1 were broken, 133 microcrystalline chopsticks of Example 2 were broken, 114 microcrystalline chopsticks of Example 3 were broken, and 386 microcrystalline chopsticks of Comparative Example 1 were broken. It can be concluded from the anti-drop test that the anti-drop performance of the microcrystalline chopsticks of Examples 1-3 is significantly better than that of Comparative Example 1. This is mainly because in step 3 of the preparation process, the microcrystalline chopsticks are kept at the microcrystalline transformation point temperature for a certain period of time, and the microcrystalline molecules inside the product have sufficient time to transform into a cubic crystal structure.

[0028] Example 4

[0029] The embodiment of the present invention provides a method for preparing a lithium silicate microcrystalline product. The difference between this embodiment and embodiment 1 is that in step 3, the product embryo is quickly heated to 952° C. and maintained for 10 minutes.

[0030] Example 5

[0031] The embodiment of the present invention provides a method for preparing a lithium silicate microcrystalline product. The difference between this embodiment and embodiment 1 is that in step 3, the product embryo is quickly heated to 955° C. and maintained for 10 minutes.

[0032] Comparative Example 2

[0033] The difference between the comparative example of the present invention and Example 1 is that in step 3, the product embryo is quickly heated to 800° C. and maintained for 10 minutes.

[0034] Drop test 2

[0035] The microcrystalline chopsticks of Examples 1, 4 and 5 and Comparative Example 2 were dropped from a height of 150 cm onto a cement floor, and the test was conducted 10,000 times respectively. The test results are as follows: 56 microcrystalline chopsticks of Example 1 were broken, 67 microcrystalline chopsticks of Example 4 were broken, 84 microcrystalline chopsticks of Example 5 were broken, and 327 microcrystalline chopsticks of Comparative Example 2 were broken. It can be concluded from the anti-drop test that the anti-drop performance of the microcrystalline chopsticks of Examples 1, 4 and 5 is significantly better than that of Comparative Example 1. This is mainly because in step 3 of the preparation process of the microcrystalline chopsticks, after the microcrystalline molecules inside the product are transformed into a cubic crystal structure, they are further heated to the microcrystalline fixed point, and the arrangement order of the microcrystalline molecules is basically fixed by maintaining the temperature for a certain period of time.

[0036] The present invention has been described in detail above through embodiments, but the contents described are only exemplary embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. The protection scope of the present invention is defined by the claims. Anyone who utilizes the technical solution described in the present invention, or a technician in the field, inspired by the technical solution of the present invention, designs a similar technical solution within the essence and protection scope of the present invention to achieve the above technical effects, or makes equal changes and improvements to the scope of application, etc., shall still fall within the scope of protection covered by the patent of the present invention.

Claims

1. A method for preparing lithium silicate microcrystals, characterized in that: It is composed of the following ingredients by weight: lithium silicate 5%-7.8% and silicon dioxide 92.2%-95%; The following steps are involved: Step 1: Weigh lithium silicate and silicon dioxide according to the ratio and mix them; Step 2: sintering the mixture into a finished product embryo; The mixed material is heated to 1500-1550°C and maintained for 0.8-1.5 hours; then poured into a mold and cooled to 580-630°C; after being taken out of the mold, it is placed in an annealing furnace and maintained at 530-570°C for 3.5-4.5 hours, then the heating is stopped, and it is naturally cooled to room temperature before being taken out of the furnace to obtain a product embryo; Step 3: gradually heat the product embryo to 730℃-745℃, and keep the constant temperature for 25-35 minutes, then quickly heat it to 952℃-955℃, and keep it for 8-15 minutes, then cool it to 580℃-630℃, and then transfer it to the annealing furnace, keep it at 530℃-570℃ for 1.8-2.3 hours, then stop heating, and naturally cool it to room temperature to obtain a microcrystalline product.

2. The preparation method according to claim 1, characterized in that In step 3, the constant temperature is maintained for 30 minutes.

3. The preparation method according to claim 2, characterized in that: In step 3, the temperature is rapidly raised to 953° C. and maintained for 10 minutes.