Abstract Calcium carbide slag was used instead of calcite and dolomite to produce sodium-calcium-calcium-bottle glass, and a preliminary analysis of the economic benefits was carried out. The experimental results show that Calcium Carbide Price 100kg can completely replace calcite and dolomite for melting sodium-calcium-bottle glass, which has good economic and social benefits.
Key words carbide slag bottle glass alternative efficiency
1 Introduction
Calcium Carbide South Africa is the waste residue discharged from the industrial production of acetylene, polyvinyl chloride, polyvinyl alcohol and other products. About 1 t of calcium carbide slag is produced per 1 t of calcium carbide produced. The carbide slag is alkaline and will not pollute the environment. At present, calcium carbide slag is used to produce cement. In this experiment, calcium carbide slag was used to produce sodium-calcium-bottle glass.
2 experimental research
2.1 Raw materials
Calcium Carbide 70-100: It was taken from organic chemical plant in Guizhou. About 30% water, after drying for use.
Silica: Taken from Guiyang Qingyan.
Dolomite: Taken from Huishui, Guizhou.
Feldspar, fluorspar, soda ash, sodium nitrate, etc.: Taken from the second glass factory in Guiyang.
The chemical composition of each raw material and the physical properties of calcium carbide slag are shown in Table 1 and Table 2, respectively.
2.2 Glass Composition Design
Because the research object is mainly the application of calcium carbide slag in the production of bottle glass for wine bottles, and considering the manufacturer's blow-blown forming method using an automatic drip-feeding machine, and it is hoped that as much as possible in the batch materials.
Table 1 Chemical composition of raw materials (%)
Raw material SiO2 CaO Al2O3 Fe2O3 Na2O MgO CaF2 As2O3 Sb2O3 Water
Silica sand 98.76 0.28 0.031 0.77 0.28 0.66
Long Rock 73.94 19.96 0.19 0.55 — 0.85
Pure alkali 58.48 1.76
Fluorite 62.40 87.00 0.38
Sodium nitrate 36.50
Carbide slag 1) 5.26 65.59 2.37 0.60 0.87
Arsenic powder 36.20 60.50
1) Before drying calcium carbide slag ingredients.
Table 2 Physical properties of carbide slag
Original moisture density Fineness (%) Particle composition (%)
(%) (more than 4900 mesh)> 0.1mm> 0 .1 to 0.0.5mm> 0.05 to 0.01mm <0.01mm
92~93 2.2~2.4 4~6 4.5 15~18 60~78 6~7
Table 3 Glass Composition (%)
Sample No. SiO2 CaO Al2O3 Na2O MgO
1# 72.45 7.39 2.75 14.80 2.52
2# 70.45 9.00 2.75 16.48 0.91
Table 4 Composition of Batches (%)
Sample No. Silica feldspar Soda Ash Carbide slag Fluorite Sodium nitrate Sodium arsenic trioxide
1# 55.74 9.77 20.21 11.89 0.99 1.40 0.60
2# 52.80 9.58 23.41 11.64 0.97 1.60 1.20
Calcium carbide slag, according to the requirements, design two kinds of glass components shown in Table 3. Fluorite was selected as the fluxing agent, arsenic antimony powder and sodium nitrate as fining agents. The composition of the corresponding glass batch materials is shown in Table 4. The CaO of the 2 batches of the batch materials were all introduced from the carbide slag, and 20% of broken glass was added.
2.3 Glass Fusion
The calcium carbide slag after drying is carefully mixed with other batch materials, added into a corundum crucible preheated to about 300° C., and continuously heated and smelted in a silicon-molybdenum rod electric furnace. According to [1], considering that there are the following reactions in the batch composed of calcium carbonate and sodium carbonate:
The calcium carbide slag replaces calcium carbonate and the above reaction decreases. When CaO is completely introduced with carbide slag, only the following reactions occur at low temperatures:
At the low temperature stage, the degree of solid phase reaction of the silicate is correspondingly weakened, and the clarification of the glass may tend to be slow. Since almost no eutectic such as CaNa2(CO3)2 is formed, the melting of the batch may be difficult. Therefore, the glass selected during the experiment has a high melting temperature and a long holding time. The temperature was 1450°C for 4h and 5h, 1500°C for 4h and 5h for comparison experiments.
During the melting process, the glass was melted by picking and drawing. See Table 4 and Table 5 for observations of the melting of the glass.
Melted glass casting molding, forming specifications for 400mm × 200mm, thickness of about 5mm, forming a good situation. Immediately after the glass was demolded, the glass was annealed in a muffle furnace having a temperature controlled at 580C.
Table 5 Glass Melting at 1450°C
Glass melting of batch materials Glass melting
No. (1450°C, 2h) (1450°C, 5h)
The glass is colorless, has a large viscosity, and has many bubbles.
1# bubble diameter, no scum, glass erosion,
There are obvious stripes in the glass.
Colorless glass, viscosity, bubble volume, and bubble diameter
2# 1# small, no scum, glass erosion, glassy
There are more obvious stripes in the glass.
The glass is colorless, has a large viscosity, has many bubbles and a small bubble diameter, has no scum, and the glass is corroded by blemishes. The glass has obvious stripes.
The glass is colorless, with less viscosity, less bubbles and smaller bubble diameters, no scum, glass erosion, and clear stripes in the glass.
From Table 4 and Table 5, we can see that when the melting temperature is low and the holding time is short, the glass melting effect is poor; under the same conditions, the melting quality of the 2# sample glass is better than that of the 1# sample.
Melting glass in industrial production is carried out in a glass tank kiln. The flow of glass liquid in the tank kiln
This facilitates the discharge of bubbles, and the glass melting test in this experiment was carried out in a laboratory high-temperature test furnace. The glass liquid was basically stationary, and the bubbles were mainly discharged by their own buoyancy. Therefore, more bubbles remained in the glass liquid. If the melting temperature is low and the holding time is short, the content of Na2O and fining agent is too small, which will inevitably worsen the poor quality of glass melting.
Table 6 Glass Melting at 1500°C
Glass melting of batch materials Glass melting
No. (1500°C, heat 2h) (1500°C, heat 5h)
Glass is colorless, less viscous, less air bubbles,
1# bubble diameter is small, no scum, glass erosion,
There are stripes in the glass.
Glass is colorless, with low viscosity, little bubbles, bubbles
2# Small diameter, no scum, glass erosion, glassy
There are few stripes in the glass.
The glass is colorless, with low viscosity, small bubbles and small bubble diameters, no scum, glass erosion, and less stripes in the glass.
The glass is colorless, its viscosity is very small, there is basically no bubble and the bubble diameter is small, there is no scum, the glass liquid erodes, and there is no stripe in the glass.
1.4 Analysis and Discussion of Physical and Chemical Properties of Glass
In this experiment, the density, light transmittance, and chemical stability of the 2# sample glass were measured by a comparative test method with a factory bottle glass product. Density was measured by the specific gravity method. The light transmittance was measured with a 722G spectrophotometer. The chemical stability was determined by the powder method. The acid resistance was determined by boiling (3 h in 1 mol/L HCl) and alkali resistance (3 h in 1N NaOH. ) and water resistance to assess. The comparative glass sample was taken from Guiyang No. 2 Glass Factory. The results of the measurement are shown in Table 5.
Table 7 Physical and chemical properties of sample glass
sample
Numbering
Acid Resistance (%) Alkali Resistance (%) Water Resistance (mg/g) Density (g/cm3) Light Transmittance (%)
Samples Comparisons Samples Comparisons Samples Comparisons Samples Comparisons Samples Comparisons
2# 0.430 0.246 2.726 2.100 0.1271 0.1550 2.4035 2.4600 85.00 86.00
From the data in Table 6, it can be seen that the difference between the measurement results of the sample glass and the comparison glass is not too large, the acid resistance and alkali resistance measurement data of the sample glass is slightly higher than that of the comparison glass, and the water resistance measurement data is slightly lower than the comparison glass, but still comply with Related standards requirements. It is estimated that this is related to the glass composition. Considering that the melting of glass is carried out in a laboratory test electric furnace, the content of Na2O in the 2#-like glass composition is as high as 16.8%, and the Na2O content can be appropriately reduced in actual production, thereby improving the chemical stability of the glass. In addition, from the results of density determination, due to differences in melting and forming operations and controls, the internal structure of the sample glass is relatively loose, the specific gravity is small, the coordination state of the filled particles is irregular, and the erosion solution easily penetrates into the loose structure, resulting in The sample glass is more likely to be eroded and therefore the measurement results are higher.
3 Preliminary analysis of economic benefits
According to preliminary estimates, the processed carbide slag has a factory price of about 60 yuan/t, and the processed calcite to the factory price is about 90 yuan/t. The production of 1t of general-purpose glass bottles and glass consumes 0.137t of glass-cutting carbide slag, which is 8.22 yuan. If CaO is entirely introduced by calcite, the consumed calcite is about 0.17t, which is equal to 15.30 yuan. It can be seen that if calcium carbide slag is used instead of calcite, it is used in production. White material bottle glass can save raw material cost about 7.08 yuan/t. Carbide slag contains almost no impurities such as Fe2O3 which are harmful to glass production and can be used to produce high-white material glass. If calculated as high-white material glass, the benefits are even more significant. The utilization of calcium carbide slag, not only pollution control, but also protect the environment, the resulting social benefits are more self-evident.
4 Conclusion
(1) Calcium carbide slag can be used as a substitute for raw materials such as calcite and dolomite to melt the sodium and calcium common bottle glass.
(2) Under laboratory conditions, when the CaO in the glass is entirely introduced from the carbide slag, the chemical stability of the glass is reduced but still meets the requirements. In actual production, chemical stability can be improved by adjusting the glass composition.
(3) The use of calcium carbide slag in the production of glass bottles and cans to control pollution and protect the environment has good environmental, economic and social benefits.
5 References
1 Northwest Light Industry Institute. Glass Technology. Beijing: China Light Industry Press, 1997.
2 Yin Xiangsheng et al. Phosphorus slag in molten soda-lime glass. Glass and porcelain enamel, 1989 (3): 33 ~ 38.
3 Nanjing Glass Fiber Research and Design Institute, Glass Test Technology Compilation Team. Glass Testing Technology. Beijing: China Building Industry Press, 1987.
The first author, Cao Jianxin, male, born in 1956, graduated from the Department of Chemical Engineering, Guizhou Institute of Technology, Associate Professor in 1982. The authors of this article are Qiu Hua, Wu Xueheng, and Zhang Xianying.
