1. The Nepheline Syenite for Glass Industry

2. The Advantages of Nepheline Syenite Used in Glass Industry Compares with Feldspar

 


The Nepheline Syenite for Glass Industry

 

Introduction

Nepheline Syenite can be used in float glass, container glass, fiber glass, opal glass, sheet glass, electrical glass and tableware glass. Nepheline Syenite provides sufficient additives of alumina and alkali in the glass batch. It has low in silica and contains no free quartz. It also has a favorable ratio of sodium oxide to potassium oxide of 2:1. Nepheline Syenite enables the glass batches to have lower viscosity and easier workability compared with Potash Feldspar. That makes it very suitable for the glass making industry.

In the glass batch, alumina acts as a matrix of stabilizer, enhancing the workability of molten glass, and increasing the resistance for scratching, breaking and chemical protection. The alkali acts as a flux agent, lowering the melting temperature of the batch and consequently reducing the quantity of high cost soda ash that has to be added. As a result, the lower fusion point of Nepheline Syenite lowers the melting temperature of the glass batch, which speeds up the melting process, improves and creates a high productivity, and in addition it saves a tremendous amount of fuel.

Our Nepheline Syenite deposit is located in Anyang, Henan province. With unique advantage compare to the other deposits in China, it has a convenient transportation network, uniform and stable quality raw ore, and huge deposit. The deposit has been investigated in detail and the confirmed quantity is more than 100 millions tons above ground and more than 150 million tons below ground.  Our processing plants are located in Anyang, Henan province and Jiangyin, Jiangsu Province, PRC. Our designed capacity is 100,000 tons per year.

Processing
 

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2. The Advantages of Nepheline Syenite Used in Glass Industry Compares with Feldspar

The Nepheline Syenite can be used in float glass, container glass, fibre glass, opal glass, sheet glass, electrical glass and tableware glass. Nepheline Syenite provides necessary additions of alumina and alkali in the glass batch. It has low in silica and contains no free quartz. It also has a favorable ratio of sodium oxide to potassium oxide of 2:1. Nepheline Syenite makes glass batches to have lower viscosity and easier workability compared with Potash Feldspar. Its high alumina and alkalis content also makes it so suitable for the glass manufacturing.

Compare with Feldspar, the advantages of Nepheline Syenite are listed as follows:-

1. The content of potassium and sodium is high in Nepheline Syenite, and it can partly replace the soda ash in glass batches.

2. The characteristic of Foidal minerals are they will not intergrow with quartz. They can decrease the melting temperature with reaction between Nepheline Syenite and quartz in glass furnace. The melting temperature would be 40C lowered than Feldspar.

3.     The content of Al2O3 is high and the content of SiO2 is low in Nepheline Syenite. So it can save the cost of transportation of Al2O3.

 4.      It can decrease the content of Fe2O3 in glass.

      Transportation Cost        

In float glass producing, the general content of Al2O3 is 1.5% in the batch. If the melting capacity is 300 ton per day. Therefore, the consumption of Feldspar is 10,950 tons/year compares with Nepheline Syenite is 7,775 tons/year. The transportation cost will then save 3,175 tons/year.

3.              Product Cost

We suppose Al2O3 content has 1.5 % in glass, the melting capacity is 300 tons per day, the content of Al2O3 of Nepheline Syenite is 21% and Feldspar is 15%.)

Names

Unit Price

    (RMB/ton)

Required

raw minerals

Per ton glass

Total

Consumption

( ton/year)

Total cost

 

(x10⁴RMB/year)

 

Conclusion

 

 

Nepheline Syenite

 

300*

 

71 Kg

 

7,775

 

223

 

Using Nepheline Syenite can save 250,000 RMB per year than using Feldspar

 

 

  Feldspar

 

 

235.20*

 

100 Kg

 

10,950

 

258

* General Ex-factory Price

According to #2 and #3, we can simply save about 408,800 RMB/year for one 300 Mt/day capacity float glass production line. Because of Nepheline Syenite’s low iron content, we can use more cheaper silica sand or other additives in glass production. In fact, Nepheline Syenite can reduce the content of iron with about 0.018% compare with Feldspar.

The industrial experiment was carried out in Hangzhou General Glass Factory in 1990.9~1991.12 by substituting the Feldspar to Nepheline Syenite. The result of this experiment indicated that by using Nepheline Syenite, melting temperature could be lowered about 38C ~ 40C, and shorten the melting time by about 1 hour. It also saved soda ash of about 0.193Kg/standard box and improved the total productivity of finished products with about 5.1%.

In short, Nepheline Syenite proves itself  in that it can save the cost of products and the cost of energy, reduces the quantity of soda ash and improve the quality of the product. In many developed countries, Nepheline Syenite has been generally used in the glass making for a long time, it is also used in factories in China, such as Nanfang Glass Group (Shenzhen), Changjiang Float,  Saint Gobain/Hanglas (Nanjing), etc.

Our company can provide the batching advice should you choose to use our Nepheline Syenite to replace your currently used Feldspar in your glass or ceramic batch..

You are welcome to contact with us for more information.

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