CN105731808A - Method for preparing glass ceramics - Google Patents

Abstract

The invention discloses a method for preparing glass-ceramics, which belongs to the field of resource utilization of yellow phosphorus slag. The yellow phosphorus slag is crushed and mixed to make it melt at a high temperature, and then micro Crystallization treatment and annealing are used to prepare glass-ceramics. The preparation process of the present invention is simple and easy. The raw material is solid waste produced in the industrial production process. The produced glass-ceramic plates can be widely used in building materials and other industries, realizing the waste slag recycling. Harmless and resourceful, it is beneficial to protect the environment.

Description

A method for preparing glass-ceramics

technical field

The invention relates to a method for preparing glass-ceramic in one step, and belongs to the technical field of industrial solid waste treatment, that is, the field of waste slag recycling.

Background technique

At present, the method of producing yellow phosphorus at home and abroad is usually the electric furnace method, that is, the mixed charge of phosphate rock, silica and coke is added to the electric furnace, and the electric energy is converted into heat energy to melt it to produce a chemical reduction reaction, so that the phosphorus in it is sublimated. The phosphorus-containing furnace gas is condensed and separated to obtain the finished phosphorus. Yellow phosphorus slag is an industrial solid waste produced during the thermal production of yellow phosphorus. Its main components are CaO and SiO ₂ , and it also contains a small amount of P ₂ O ₅ , Al ₂ O ₃ , Fe ₂ O ₃ , and F. About 8-10 tons of slag is discharged for every 1 ton of yellow phosphorus produced. At present, the disposal methods of yellow phosphorus slag at home and abroad are mainly used as cement additives, roadbed materials, silicon-calcium fertilizers, etc. These resource utilization methods have low added value and consume less slag. As a high-grade building decoration material, glass-ceramics has high added value. Using yellow phosphorus slag to prepare glass-ceramics can not only solve the problem of yellow phosphorus slag stockpiling, but also facilitate the comprehensive utilization of yellow phosphorus slag. The discharge of yellow phosphorus slag in Yunnan Province is very large, and the load on the environment is also very large. Therefore, the treatment and recycling of yellow phosphorus slag is extremely urgent. At present, the comprehensive utilization of yellow phosphorus slag has become a research hotspot in the field of solid waste treatment and resource utilization, and it is also an urgent need for the sustainable development of phosphorus chemical industry.

After many years of efforts by domestic and foreign scientific researchers, some methods of comprehensive utilization of yellow phosphorus slag have been developed, including the use of yellow phosphorus slag in the production of cement additives, building materials such as bricks and boards, and silicon-calcium fertilizer. However, due to the impact of technology and economy, there has been no conclusion as to which method is the best resource utilization method, which has caused the large-scale utilization of yellow phosphorus slag to stagnate. Glass-ceramic, also known as glass-ceramic, is a large number of uniform tiny crystals formed inside the amorphous basic glass by controlling the heat treatment system. It has attracted more and more attention because of its low water absorption and high mechanical strength.

The present invention utilizes large amount of slag to naturally cool yellow phosphorus slag to prepare glass-ceramic in one step, which makes full use of Ca, Al and Si resources in solid waste yellow phosphorus slag. Using yellow phosphorus slag to produce glass-ceramics can not only reduce the pressure on the phosphorus chemical industry and reduce the impact of yellow phosphorus slag on the ecological environment by consuming yellow phosphorus slag on a large scale, but also can produce high economic and economic benefits.

Invention patent CN101519277A discloses a method for producing a rolled-type glass-ceramic decorative plate with phosphorus slag. Among them, the phosphorus slag used to remove iron and coal ash impurities is 40%~65%, the quartz sand is 35%~50%, the soda ash is 8%~14%, the alumina is 3%~8%, and the zinc oxide is 1%~ 6%, magnesium oxide 1%~5%, barium carbonate 1%~6%, coloring agent 0.5%~4%, the molten glass in the high temperature resistant pool furnace is reduced to about 1200℃~1260℃ for molding , annealing treatment between 900 ° C ~ 960 ° C, and then cooling. Invention patent CN103253867A discloses a technology for preparing glass-ceramics from molten yellow phosphorus slag. According to the CaO-Al ₂ O ₃ -SiO ₂ ternary system phase diagram, it is determined that the yellow phosphorus slag accounts for 51-78wt% of the total raw materials, and the auxiliary materials rich in SiO ₂ and Al ₂ O ₃ are added to the molten yellow phosphorus slag. Carry out clarification at high temperature and cast molding, heat preservation at 600°C to 650°C for 1h to 2h, annealing, and subsequent nucleation and crystallization processes to obtain glass-ceramic. Invention patent CN1868946A discloses a waste slag glass-ceramic and its preparation method. The raw materials for the preparation of the waste slag glass-ceramics are mainly composite wastes of yellow phosphorus slag, tantalum-niobium tailings and waste glass, and auxiliary materials are added according to the chemical composition requirements of the waste slag glass-ceramics, the yellow phosphorus slag, tantalum-niobium tailings , Waste glass and auxiliary materials The weight percentages of each raw material are: yellow phosphorus slag 28-55%, tantalum-niobium tailings 10-30%, waste glass 10-18%, auxiliary materials 3-45%. Invention patent CN101037298A discloses a method for comprehensively utilizing yellow phosphorus slag and tail gas to produce glass-ceramics. The invention patent uses nozzles arranged in an orderly manner on the roof of the melting furnace to mix the washed, purified and dried yellow phosphorus tail gas with oxygen and then burn it, maintaining the temperature in the furnace at 1450°C to achieve the purpose of effectively utilizing the heat released by the combustion of the yellow phosphorus tail gas. Add silicon, aluminum, and sodium raw materials directly to the yellow phosphorus molten slag in a melting furnace, and then undergo nucleation and crystallization to obtain a finished glass-ceramic product.

At present, among the publicly available recycling methods for preparing glass-ceramics from waste slag, most of them use 40-70% of waste slag and the two-step method of nucleation and crystallization to prepare glass-ceramic, which has a large amount of slag. Smaller, larger energy consumption and other problems, and due to the downturn in the yellow phosphorus industry in recent years, its economic benefits are weakening day by day. The present invention realizes one-step preparation of glass-ceramics by controlling the cooling rate and heat preservation time on the premise of large amount of slag used, the process is easy, the energy consumption is greatly reduced, and the economy is good.

Contents of the invention

The object of the present invention is to provide a method for preparing glass-ceramics, which is to crush and mix the yellow phosphorus slag, make it melt into a liquid state at a high temperature, and then go through the process of microcrystallization treatment and annealing in the cooling process. Preparation of glass-ceramics. Specifically include the following steps:

(1) Yellow phosphorus slag is crushed, ground and sieved to obtain yellow phosphorus slag powder;

(2) According to the liquidus temperature range in the CaO-Al ₂ O ₃ -SiO ₂ ternary phase diagram at different temperatures, it is determined that the yellow phosphorus slag accounts for 61~83wt% of the total raw materials, and the auxiliary materials rich in SiO ₂ account for the total raw materials The 8~16wt% of Al ₂ O ₃ rich auxiliary materials accounted for 8~23wt% of the total raw materials. After mixing the yellow phosphorus slag powder and 80-200 mesh auxiliary materials, they were kept at 1350~1450°C for 90~120min to make them all Melt, then cool down to 850-950°C at a cooling rate of 1-5°C/min and keep warm for 120-180 minutes, then cool down to room temperature at a cooling rate of 8-15°C/min to obtain glass-ceramics.

The _SiO2 -rich auxiliary material is one of vein quartz, quartz sand, quartzite, sandstone, silica, opal, and diatomite, and the content of _SiO2 in the auxiliary material is greater than 70%.

The auxiliary material rich in Al ₂ O ₃ is bauxite, and the content of Al ₂ O ₃ in the auxiliary material is greater than or equal to 90%.

The principle of the present invention is to use the phase diagram of the CaO-Al ₂ O ₃ -SiO ₂ ternary system to redesign the glass-ceramic with a large amount of slag to improve the utilization rate of yellow phosphorus slag; and to use the principle of phase separation in the glass to During the cooling process, by controlling the cooling rate, the solid-liquid phase separation occurs inside the glass, resulting in fine grains, and the grains inside the glass grow into crystals for a period of time.

Beneficial effects of the present invention:

(1) The method for preparing glass-ceramic from yellow phosphorus slag in the present invention has a simple and easy process, and glass-ceramics with excellent performance can be prepared through processes such as melting in a high-temperature state, microcrystallization treatment, and annealing;

(2) The present invention can prepare glass-ceramics of magnesia feldspar and calcium aluminum feldspar crystal phase, form a circular economic chain of phosphorus slag resource utilization, and realize the harmless and high-value utilization of phosphorus slag;

(3) The microcrystallization treatment carried out in the cooling process of the present invention can greatly save energy, simplify heat treatment steps, and increase economic value.

Description of drawings

Fig. 1 is the XRD pattern of the glass-ceramic that the embodiment of the present invention 1 makes;

Fig. 2 is the SEM picture of the glass-ceramic that the embodiment of the present invention 1 makes;

Fig. 3 is the XRD pattern of the glass-ceramic that the embodiment of the present invention 2 makes;

Fig. 4 is the SEM picture of the glass-ceramic that the embodiment of the present invention 2 makes;

Fig. 5 is the XRD pattern of the glass-ceramic that the embodiment of the present invention 3 makes;

Fig. 6 is the SEM figure of the glass-ceramics that the embodiment of the present invention 3 makes;

Fig. 7 is the XRD figure of the glass-ceramics that the embodiment 4 of the present invention makes;

Fig. 8 is the SEM picture of the glass-ceramic that the embodiment of the present invention 4 makes;

Fig. 9 is the XRD figure of the glass-ceramics that comparative test makes;

Fig. 10 is a SEM image of the glass-ceramics prepared in the comparative test.

detailed description

The present invention will be further described in detail below in conjunction with the examples, but the protection scope of the present invention is not limited to the content.

Embodiment 1: the yellow phosphorus slag described in the present embodiment is the solid waste that thermal method produces yellow phosphorus technique to produce, and the composition of its raw material is as shown in table 1:

Table 1: Main components of yellow phosphorus slag raw materials

;

(1) Yellow phosphorus slag is crushed, ground, and sieved through an 80-mesh sieve to obtain yellow phosphorus slag powder;

(2) According to the liquidus temperature range in the CaO-Al ₂ O ₃ -SiO ₂ ternary phase diagram at different temperatures, it is determined that the yellow phosphorus slag accounts for 82.35wt% of the total raw materials, and the auxiliary materials rich in SiO ₂ account for 82.35% of the total raw materials. 8.43wt% (quartz sand, SiO ₂ is 95% in auxiliary materials), rich in Al ₂ O ₃ auxiliary materials account for 9.22wt% of the total amount of raw materials (bauxite, Al ₂ O ₃ content is 92% in auxiliary materials); (1) The obtained yellow phosphorus slag powder and auxiliary materials of 100~200 mesh are placed in an alumina crucible and placed in a high-temperature ceramic fiber muffle furnace, kept at 1400°C for 120min, and then cooled to 900°C at a cooling rate of 5°C/min. After holding at ℃ for 130min, then cooling down to room temperature at a cooling rate of 8℃/min, the glass-ceramics can be obtained (see Figure 1, 2).

According to XRD analysis, the main crystal phases in the glass-ceramics are Ca ₂ MgSi ₂ O ₇ (magnesia feldspar) and Ca ₂ Al ₂ SiO ₇ (calcium-alumina feldspar), and the average The grain size is 16.2nm, and the crystallinity is 61.30%. It can be seen from Figure 2 that the grain distribution in the glass-ceramics is relatively dispersed, and the grains are small and irregular in shape.

Embodiment 2: in the present embodiment, the yellow phosphorus slag is the solid waste that thermal method produces yellow phosphorus technique, and the composition of its raw material is as shown in table 2:

Table 2: Main components of yellow phosphorus slag raw materials

;

(1) Yellow phosphorus slag is crushed, ground, and sieved through an 80-mesh sieve to obtain yellow phosphorus slag powder;

(2) According to the temperature range of the liquidus line in the CaO-Al ₂ O ₃ -SiO ₂ ternary phase diagram at different temperatures, it is determined that the yellow phosphorus slag accounts for 81.45wt% of the total raw materials, and the auxiliary materials rich in SiO ₂ account for 81.45% of the total raw materials. 10.32wt% (silica, SiO in auxiliary materials is 98%), rich in Al ₂ O ₃ auxiliary materials account for 8.23wt% of the total amount of raw materials (bauxite, Al ₂ O ₃ content in auxiliary materials is 91%) _; the step ( 1) Put the obtained yellow phosphorus slag powder and 80~100 mesh auxiliary materials in an alumina crucible and place it in a high-temperature ceramic fiber muffle furnace, keep it at 1350°C for 120min, and then cool it down to 870°C at a cooling rate of 1°C/min After heat preservation for 170min, then cool down to room temperature at a cooling rate of 10°C/min to obtain glass-ceramics (see Figures 3 and 4).

According to XRD analysis, the main crystal phases in the glass-ceramics are Ca ₂ MgSi ₂ O ₇ (magnesia feldspar) and Ca ₂ Al ₂ SiO ₇ (calcium-alumina feldspar), and the average The grain size is 23.1 nm, and the crystallinity is 66.05%. It can be seen from FIG. 4 that different crystal phases in the glass-ceramics present different shapes, and the grain size is larger than that in Example 1.

Embodiment 3: in the present embodiment, the yellow phosphorus slag is the solid waste produced by the process of producing yellow phosphorus by thermal method, and the composition of its raw material 3 is as shown in table 3:

Table 3: Main components of yellow phosphorus slag raw materials

;

(1) Yellow phosphorus slag is crushed, ground, and sieved through an 80-mesh sieve to obtain yellow phosphorus slag powder;

(2) According to the liquidus temperature range in the CaO-Al ₂ O ₃ -SiO ₂ ternary phase diagram at different temperatures, it is determined that the yellow phosphorus slag accounts for 80.45wt% of the total raw materials, and the auxiliary materials rich in SiO ₂ account for 80.45% of the total raw materials. 11.32wt% (vein quartz, SiO ₂ in auxiliary materials is 99%), rich in Al ₂ O ₃ auxiliary materials account for 8.23wt% of the total amount of raw materials (bauxite, Al ₂ O ₃ content in auxiliary materials is 95%); (1) The obtained yellow phosphorus slag powder and auxiliary materials of 100~150 mesh are placed in an alumina crucible and placed in a high-temperature ceramic fiber muffle furnace, kept at 1450°C for 90min, and then cooled to 950°C at a cooling rate of 3°C/min. After holding at ℃ for 120min, then cooling down to room temperature at a cooling rate of 15℃/min, the glass-ceramics can be obtained (see Figures 5 and 6).

According to XRD analysis, the main crystal phases in glass-ceramics are Ca ₂ MgSi ₂ O ₇ (magnesia feldspar) and CaAl ₂ Si ₂ O ₈ (anorthite). The grain size is 33.3nm, and the crystallinity is 77.41%. It can be seen from Figure 6 that the grain sizes in the glass-ceramics are different, but the distribution is relatively dense, and it also presents an irregular shape.

Embodiment 4: in the present embodiment, the yellow phosphorus slag is the solid waste that thermal method produces yellow phosphorus technique, and the composition of its raw material is as shown in table 4:

Table 4: Main components of yellow phosphorus slag raw materials

;

(1) Yellow phosphorus slag is crushed, ground, and sieved through an 80-mesh sieve to obtain yellow phosphorus slag powder;

(2) According to the temperature range of the liquidus line in the CaO-Al ₂ O ₃ -SiO ₂ ternary phase diagram at different temperatures, it is determined that the yellow phosphorus slag accounts for 63.21wt% of the total raw materials, and the auxiliary materials rich in SiO ₂ account for 63.21wt% of the total raw materials. 31.05wt% (diatomite, SiO ₂ in auxiliary materials is 75%), auxiliary materials rich in Al ₂ O ₃ account for 5.74wt% of the total raw materials (bauxite, Al ₂ O ₃ content in auxiliary materials is 96%); The yellow phosphorus slag powder obtained in step (1) and auxiliary materials of 120~180 meshes were placed in an alumina crucible and placed in a high-temperature ceramic fiber muffle furnace, kept at 1380°C for 100 minutes, and then cooled at a cooling rate of 2°C/min to After holding at 930°C for 140min, then cool down to room temperature at a cooling rate of 10°C/min to obtain glass-ceramics (see Figures 7 and 8).

According to XRD analysis, the main crystal phases in glass-ceramics are Ca ₂ MgSi ₂ O ₇ (magnesia feldspar) and CaAl ₂ Si ₂ O ₈ (anorthite). The grain size is 19.9nm, and the crystallinity is 82.41%. It can be seen from Figure 8 that the grains in the glass-ceramics are densely distributed, mainly spherical and needle-shaped, and the crystallinity is high.

Embodiment 5: in the present embodiment, yellow phosphorus slag is the solid waste that heat method produces yellow phosphorus technique to produce, and the composition of its raw material is as shown in table 5:

Table 5: Main components of yellow phosphorus slag raw materials

;

(1) Yellow phosphorus slag is crushed, ground, and sieved through an 80-mesh sieve to obtain yellow phosphorus slag powder;

(2) According to the liquidus temperature range in the CaO-Al ₂ O ₃ -SiO ₂ ternary phase diagram at different temperatures, it is determined that the yellow phosphorus slag accounts for 75.26wt% of the total raw materials, and the auxiliary materials rich in SiO ₂ account for 75.26% of the total raw materials. 21.35wt% (sandstone, SiO ₂ in auxiliary materials is 95%), rich in Al ₂ O ₃ auxiliary materials account for 3.39wt% of the total amount of raw materials (bauxite, Al ₂ O ₃ content in auxiliary materials is 95%); the step ( 1) The obtained yellow phosphorus slag powder and auxiliary materials of 150~180 mesh are put in an alumina crucible and placed in a high-temperature ceramic fiber muffle furnace, kept at 1400°C for 90min, and then cooled to 920°C at a cooling rate of 4°C/min After 120 minutes of heat preservation, the temperature is lowered to room temperature at a cooling rate of 12°C/min to obtain glass-ceramics.

According to XRD analysis, the main crystal phases in glass-ceramics are Ca ₂ MgSi ₂ O ₇ (magnesia feldspar) and CaAl ₂ Si ₂ O ₈ (anorthite). The grain size is 24.5nm, and the crystallinity is 78.41%. The crystal grains in the prepared glass-ceramics are needle-like and fiber-like in shape, dense in structure and high in crystallization degree.

Attachment: Comparison with the patent (a process technology for preparing glass-ceramics from molten yellow phosphorus slag):

The composition of raw material is as shown in table 6:

Table 6: Main components of yellow phosphorus slag raw materials

According to the CaO-Al ₂ O ₃ -SiO ₂ ternary system phase diagram, the raw material formula for preparing glass-ceramic was determined. The yellow phosphorus slag accounted for 75.60wt% of the total raw material, and the auxiliary materials rich in SiO ₂ accounted for 19.39wt% of the total raw material ( Quartz sand, _SiO2 is 95% in the auxiliary material), _Al2O3 auxiliary material accounts for _5.01wt % of the raw material total amount (the auxiliary material alumina is commercially available chemically pure alumina); the auxiliary material is added in the yellow phosphorus slag, at 1350 Heat the base glass for 120 minutes at ℃ to melt the basic glass raw material, then quickly pour the basic glass melt into the mold for molding, and heat it in the furnace body at 600 °C for 2 hours before annealing; raise the base glass temperature to 790 °C at a nucleation rate of 5 °C/min Keep it warm for 2 hours, then raise it to 1080°C at a crystallization heating rate of 3°C/min and keep it warm for 1.5 hours, then cool naturally with the furnace to obtain glass-ceramics.

According to XRD analysis (see Figure 9), the main crystal phases in glass-ceramics are wollastonite (CaSiO ₃ ) and ferropyroxene ((Ca, Fe)SiO ₃ ), and the crystallite The average grain size in the glass is 50.6nm, and the crystallinity is 41.87%. From Figure 10, a large number of spherical grains can be observed and the overall distribution is relatively uniform, and the growth and development of the crystals is good.

Claims (3)

1. A method for preparing glass-ceramics, characterized in that: according to the liquidus temperature range in the CaO-Al ₂ O _{3 -} SiO ternary phase diagram at different temperatures, it is determined that the yellow phosphorus slag accounts for 61% of the total amount of raw materials 83wt%, rich in SiO ₂ auxiliary materials accounted for 8~16wt% of the total raw materials, rich in Al ₂ O ₃ auxiliary materials accounted for 8~23wt% of the total raw materials, the yellow phosphorus slag powder after grinding and screening was mixed with 80~200 mesh After mixing auxiliary materials rich in SiO ₂ and rich in Al ₂ O ₃ , place them at 1350~1450°C for 90~120 minutes to melt them all, and then cool down to 850~950°C at a cooling rate of 1~5°C/min and hold for 120 minutes. After ~180min, cool down to room temperature at a cooling rate of 8~15°C/min to obtain glass-ceramics. 2. The method for preparing glass-ceramics according to claim 1, characterized in that: rich in SiO _The auxiliary material is one of vein quartz, quartz sand, quartzite, sandstone, silica, opal, diatomaceous earth, and the auxiliary material The content of SiO ₂ is greater than 70%. 3. The method for preparing glass-ceramic according to claim 1, characterized in that: the auxiliary material rich in Al ₂ O ₃ is bauxite, and the content of Al ₂ O ₃ in the auxiliary material is greater than or equal to 90%.