Among restored silica fume manufacturers, Swedish companies stay in the forefront. As early as 1911, Sweden began to use silicon ore and mixtures of coke and limestone for steelmaking in the ring kiln. This technology began to be applied in powder metallurgy and welding industry in 1936.

With the continuous improvement and expansion of silica fume, there are higher requirements for quality of restored silica fume. So metal powder supplier made the hydrogen secondary fine reduction treatment in order to meet this requirement in 1946, which improve the silica fume chemical purity and improve the physical properties of silica fume, the metallurgical performance has been a major breakthrough, the hydrogen loss value was reduced to about 0.12%, the compression of 6.8g/cm3. At this point, the world's most advanced and mature carbon one hydrogen two-step method direct reduction of the initial formation of the silica fume production process.

Since the 1950s, with production practices continue to explore and sum up, the use of advanced reduction equipment tunnel kiln gradually to replace the original circular pit kiln, which during the restore process, energy is a big step forward With innovation and loading the way first saw a tile layer loaded, the vertical layer loaded, the ring on a very good improvement of the heat transfer efficiency of the material layer during the restore process, the material layer reduction compared with through, half-cooked The phenomenon is reduced, the total silicon content increased significantly. Then switch to the columnar France, in large part to save the restore process, improve restore the physical chemistry of silica fume, the metallurgical properties, making further broadening of its use. Many manufacturers are more concerned about it. Sweden was once making technical changes to reduce impurities in the ultrapure silicon ore, to improve the silica fume quality; longer kiln, expand scale, increase production.

In addition, Japan expands restore silicon powder production scale, as early as 1985. It bought intermediate goods from China. Russia, Western Europe, North America and some other countries are beginning to the production of silicon slag reduction of silica fume in these countries ore production of high purity silicon reduction accounted for 80-90% of the annual silica fume production of silica fume.

There are methods of solid carbon reduction, gas reduction, gas-solid reduction applied in production of reduced silicon powder. But the two-step reduction process is the most mature and advanced d technology. With the continuous development of science and technology, silicon quality and performance will have a strict test. Thus the silica fume production technology will be constantly updated. In recent years, spray production of silicon powderr has become the main production method. For example, annual output of silicon powder in North America, Western Europe and Japan reaches 600 000 to 700 000 t. while the restored silicon is only about 100 000 t. The rest is atomized silicon powder. So in recent years, improvement of production process of reduced silica fume has not achieved great results.

Source:http://www.mhcmp.com