Silicon block, also known as crystalline silicon or industrial silicon, is an industrially purified elemental silicon that can be used to produce high-purity semiconductor materials. The grade of metallic silicon block reaches 99.999 (5N). It is mainly used to produce organic silicon and is used in 3C industry. It can also be used as an additive for non-ferrous alloys in many aspects, such as manufacturing alloys for special purposes.
Metal silicon blocks for aluminum alloys: Industrial silicon used in the aluminum alloy smelting industry generally has different particle sizes. The traditional method of adding silicon is to pour aluminum alloy silicon directly on the surface of the molten aluminum after the aluminum ingot is melted. The disadvantage of this adding method is that large particles of bulk silicon will directly enter the aluminum liquid due to gravity, and will melt quickly after stirring. Due to its small size and light weight, powdered silicon with smaller particles will float on the surface of the aluminum liquid and is easily covered by alumina. As a result, in the subsequent slag removal process, if the oxide slag coated with powdered silicon can be removed, The recovery rate of Si is low. If it cannot be removed, powdered silicon will remain in the aluminum alloy to form hard spots, seriously affecting product quality and causing difficulties in subsequent processing.
The production method of aluminum alloy includes the following steps: (1) Add molten aluminum and aluminum ingots to the melting furnace; (2) Add silicon or master alloy: First, add the metal silicon block to the melting furnace for smelting, at 730 ~ 760 degrees Stir thoroughly for half an hour at 730 to 760 degrees, then add the master alloy to the smelting furnace after completely dissolving it, stir evenly for half an hour at 730 ~ 760 degrees, so that the added raw and auxiliary materials are completely dissolved, and the AL-Si system is made; (3 ) The prepared aluminum melt is subjected to slag removal and degassing, and the degassing is carried out with powder refining agent and nitrogen to obtain an aluminum melt with higher purity; (4) Casting. The traditional method of smelting aluminum alloy and adding metal silicon blocks to the aluminum alloy will inevitably have the above problems.
Put the metal silicon block for aluminum alloy to be added into the aluminum foil bag, vacuum-pack it, and put the metal silicon addition bag for aluminum alloy into the aluminum liquid. The structure of the alloy adding bag is to use an aluminum foil bag to contain the alloy element powder required for the production of aluminum alloy, and the bag is evacuated. In this method, alloying element powders are placed into aluminum foil bags and vacuum packed. Although the problem of floating powder is solved, it requires the purchase of additional aluminum foil bags and vacuum packaging equipment, making the process complex and low in practicability. The purpose of using aluminum alloy metal silicon blocks is to overcome the shortcomings of the existing technology and provide a new method of adding industrial silicon during the aluminum alloy smelting process. The process is simple, but it can effectively improve the silicon recovery rate and the quality of the aluminum alloy.
Due to its high gravity, the aluminum alloy metal silicon block can sink directly into the aluminum liquid and can be fully melted by stirring. Powdered silicon is loaded into a duster with nitrogen as the carrier. By adjusting the flow rate of nitrogen, it is directly injected into the middle and lower part of the smelting furnace to melt it in the aluminum liquid to prevent it from floating on the surface of the aluminum liquid, being wrapped by oxides, reducing the recovery rate or forming hard spots in the aluminum alloy, affecting product quality. The use of aluminum alloy metal silicon blocks not only improves the recovery rate of silicon, but also significantly improves the quality of the aluminum alloy, which is reflected in the increase in tensile strength and elongation.
