A white solid substance separated by desilication operation is called silicon slag. Due to the presence of alumina and alkali in it, it is generally returned to the preparation of raw materials for incorporation.
Editing and broadcasting of silicon slag separation

In the production of alumina, the crude solution after desilication treatment contains a large amount of impurities such as silicon slag and red mud, which cannot be directly decomposed. In order to ensure that the product alumina meets the national standards, the crude solution must be clarified and separated after desilication to produce a pure and transparent sodium aluminate solution. When processing the solution after desilication, leaf filters or pressure filters are commonly used in industry to separate the silicon residue in the desilication solution. The task of the silicon slag separation process is to separate the desilication slurry sent from the desilication process to obtain sodium aluminate semen with desilication index, iron aluminum ratio and floating matter content meeting the process requirements, and then send the semen to carbonation for decomposition. The quality of semen is the key to ensuring the quality of the final product alumina.
The sodium aluminate solution after desilication enters the silicon slag settling tank through the distribution box, and the settled silicon slag is pumped out of the bottom flow tank and sent to the silicon slag filter for filtration. The overflow of the settling tank goes to the original liquid tank (overflow tank) and is pumped into the leaf filter. The silicon residue filtered from the leaves is first flushed into the silicon residue tank with a solution, and then pumped to the silicon residue filter. The semen obtained from the leaves is then fed into the semen tank and pumped to the decomposition tank for decomposition. The filtrate from the silicon slag filter returns to the original liquid tank of the silicon slag settling tank and the overflow from the settling tank enters the leaf filter. The silicon slag filtered out by the silicon slag filter is sent to the raw material section for batching. Among them, the reason why the desilication slurry is first sent to the silicon slag settling tank for sedimentation before entering the leaf filter is to reduce the load of the leaf filter, so that most of the silicon slag is separated from the solution in the settling tank, and only the overflowing solution is sent to the leaf filter for leaf filtration. This can reduce the load of the leaf filter, thereby reducing the number of leaf filters.
Editing and broadcasting of silicon slag properties
Silica slag is an aqueous mixture of zircon sand obtained by alkali melting, acid leaching and water dissolution. It is a colloidal polymer with high water content. Its appearance is light yellow green, sponge like, with strong adsorption and complex structure. The main components are silicic acid () and water, which are acidic after water immersion, with pH<1 and a solid content of about 20%. Due to the chemical reactions that occur during the production process, there are also silicic acid series products such as metasilicic acid (), orthosilicic acid (), dimetasilicic acid (), and triorthosilicic acid () in the silicon slag, as well as sodium silicate (), unreacted zirconium sand (), and zirconium oxychloride (), whose structures are not yet clear. Due to intermittent alkali melting operation, different particle size composition of zircon sand, and different decomposition rates of zircon sand, the content of and fluctuates greatly. The general composition is shown in the right figure.
Silicon slag can not only be used for producing white carbon black, but also can be used as a building material cement auxiliary material or to make ordinary refractory bricks after treatment.

The following introduces a method of producing building material cement excipients using silicon slag. This method uses acidic silicon slag with recovered zirconium, which has a moisture content of about 80% and a HCI content of 2% to 3%. It is first mixed with waste alkali water containing about 10% NaOH in production, with a pH value of 6. Then, an appropriate amount of coal ash generated during alkali melting is added, and the calcium slag is neutralized with waste acid. After pressure filtration, dehydration, and drying, medium calcium silicon slag can be obtained. The product can be used for road construction and wall bricks, etc. The process flow is shown in the right figure.

Here is another introduction to a silicon slag treatment method. This method uses the waste heat from high-temperature sintering of zirconium sand and calcination of zirconium oxychloride as the heat source, and sends the silicon slag into a drying furnace to remove the water from the silicon slag. The dry silicon slag can be used as a raw material for refractory materials and glaze materials. This method can fully utilize production waste heat and is simple and convenient. In addition, silicon slag can be used to produce water glass from waste alkali solution.

Price-off Promotion Ferro Silicon Slags/ Silicon Slags/ silicon metal slag/Silicon slag with Best Quality
Silicon metal Slags USD 180/MT FOB China
Ferro Silicon Slags USD 350/MT FOB China
Our silicon slag have two grade: ferro silicon slag and silicon metal slag.

Si: 35%-50%
Size: Nature Size
We often supply Nature size directly from Ferro Silicon or Silicon Metal factory. If client need make size can make it during using.
We only supply the silicon slag from the silicon metal and ferrosilicon factories. There is no selection before leave factory, directly loaded into truck or into big bags. The SI content is 40% around or higher.

 Products Description             
 Silicon Slag

Silicon Slag is a by-product of silicon metal's production. It contains large metallic silicon and impurities of other elements, can be used as a good deoxidizer in molten steel deoxidization, meanwhile it can also purify the liquid steel. For its low price and good effect, steel-mills use it as a substitute of ferrosilicon. Regular size are powder at 0-5 or 0-10 mm. Silicon briquette is made from silicon slag powder, they are with similar features and applications.
Brief introduction: Off grade silicon metal like its name means, is unqualified metallurgical si metal. Silicon content used to be 93% min but recent years with advanced production technique, the purity of off grade silicon metal became higher than 95%, 97%. Because it's relative high purity and surprising cheap price. It is very suitable to replace model Si 553 in some area. In some Aluminum Alloy model, only small quantity of silicon is needed. And some model didn't require very strict Silicon or Fe, Ca content. So off grade silicon is very good substitute and very efficiency material to save cost . Features and usage: * Aluminum alloy ingot production, as additive of silicon. * Dioxidizer in steelmaking as replacement of ferrosilicon or high purity silicon metal. * Other replacement of higher grade silicon metal, metallurgical, chemical or other industries, with its much cheaper price. *As an additive to non-ferrous alloys, industrial silicon is also used as an alloying agent for silicon steel with strict requirements, and as a deoxidizer for smelting special steels and non-ferrous alloys.