Worries and Hopes for Inorganic Silicide Industry     

By Ge Yongsheng, Laizhou Welfare Sodium Silicate Co Ltd   

In China, major industrial silicides are sodium silicate, silica gel, silica white, silica sol, potassium silicate and molecular sieves. Among them, molecular sieves are monopolized by CNPC (China National Petroleum Corporation) and Sinopec Group in China. The two oil giants together produce and consume about 160 000 tons of molecular sieves a year. Major molecular sieve producers include PetroChina Lanzhou Petrochemical Company, Sinopec Qilu Petrochemical Company and Sinopec Baling Petrochemical Company. Besides CNPC and Sinopec Group, other companies produce about 40 000 tons of molecular sieves a year in total, mainly for refineries that do not belong to the two giants and CNOOC (China National Offshore Oil Corporation). With the development of China's refining industry, the output of molecular sieves has increased year by year, and new varieties of molecular sieves are also constantly invented. In recent years, the development of other silicides is very uneven in China. For example, the silica gel industry develops very slowly. China's annual output of silica gel, mainly of common silica gel, always hovers around 150 000 tons. Potassium silicate is mainly produced with the wet process and is sold mostly in the form of sodium potassium silicate. In China, its annual output is about 50 000 tons. At present, among inorganic silicides, the fastest growing are silica white and sodium metasilicate.

1.  China's silica white output ranks first in the world

Silica white is mainly used in tire and rubber shoes industries. Its capacity will exceed 1 million t/a in 2010. Most of its manufacturers use America's PPG process. The output of silica white in Shandong and Fujian provinces is very huge.
   The rapid development of silica white is driven by the rubber industry. Fujian province is China's major footwear production cluster. Neighboring countries and regions have transferred a number of footwear plants here. Shandong province is China's major tire production place. Out of China's top 10 tire companies, five are located in Shandong province. This is the main reason why Fujian and Shandong provinces have become two major silica white production bases in China.
   In 2009, China's silica white output was nearly 800 000 tons. Zhuzhou Xinglong Chemical Industrial Co Ltd is China's largest silica white producer. Its silica white output reached 96 000 tons in 2009. Among the world's five largest silica white producers, four have set up their silica white factories in China. Years ago, Germany's Degussa (now Evonik) set up a joint silica white plant Jialian White Carbon Black (Nanping) Co Ltd in Nanping, Fujian province. In 2009, the silica white output of this joint venture was 68 000 tons, ranking second in China. More than 10 years back, Rhodia of France has built a 30 000 t/a silica white factory in Qingdao of Shandong province. Currently, Rhodia is constructing a 170 000 t/a project in the development zone of Qingdao, the first phase 85 000 t/a is scheduled for startup in July 2010. JM Huber Corporation's 40 000 t/a toothpaste-oriented silica white plant in Qingdao has successfully had trial production and will operate at its full capacity in the second half of 2010. Oriental Silicas Corp acquired the silica white plants of PPG in China's Nanchang and Lianyungang cities. It is expected that in 2010, China's rubber consumption will reach 7 million tons and its demand for silica white will further increase.

2. The housing industry stimulates the development of the sodium metasilicate industry

The rapid development of China's sodium metasilicate industry is mainly driven by the rapid development of China's housing industry in recent years. Currently, China's sodium metasilicate capacity is close to 500 000 t/a. In early years, sodium metasilicate was mainly used as a water reducer in dying/printing, detergent and ceramic industries. As the housing industry has become one of China's pillar industries, the construction ceramics industry has also developed very fast. Sodium metasilicate is an essential additive for ceramic products. Because its production process is simple and the entry threshold is not high, a number of small enterprises have entered this industry. In Zibo, Shandong province alone, there are hundreds of small sodium metasilicate producers, with a combined annual output of 150 000 tons.

3. The production of 4A zeolite declines

Among molecular sieves, 4A zeolite is an additive for detergents. In China, its capacity once reached nearly 500 000 t/a. In washing powder, 4A zeolite and sodium metasilicate are added to replace sodium tripolyphosphate. But a few years ago, a survey report for the water pollution of Taihu Lake pointed out that 75% of phosphorus in the polluted water of Taihu Lake comes from phosphorus fertilizers in the soil, 20% from the decay of plants and human and animal feces and urine, and only less than 5% from domestic water. This report has prompted the production and use of sodium tripolyphosphate. Because the decontamination capabilities of 4A zeolite and sodium metasilicate are far less than that of sodium tripolyphosphate, 4A zeolite is not welcome in the detergent industry any longer, and its output has declined in recent years.

4. The development of sodium silicate needs to break through the bottleneck of raw materials

Sodium silicate is the matrix product of silica white, sodium metasilicate and 4A zeolite. Its development is mainly driven by the above-mentioned three products. The use of sodium silicate in binders has now been nearly replaced by other products, so its use in binder is very small now. In addition, a small amount of liquid sodium metasilicate is used in detergents. Every year, China exported about 200 000 tons of solid sodium metasilicate to neighboring countries and regions as a raw material of downstream products.
   China's total output of sodium silicate is more than 2 million tons (based on solid product). Its production process is dominated by the dry method, which accounts for 85% of the total output. The quality of China's sodium silicate product has reached international standards. China has now become a net exporter of sodium silicate. Currently, only a small amount of wet-process sodium silicate enters the market, mostly for the preparation of sodium metasilicate.
   Currently, the raw material for the production of high-quality sodium silicate in China is mainly quartz imported from Vietnam or Australia, so it is relatively costly. Because of limited resources, the import of quartz may be restricted in the future.