A Method for Extracting Sapphire Ingots Stuck in Tungsten Crucible
Posted by Cathie Montanez on August 30, 2019 3:40 AM EDT
It requires four steps to extract the stuck sapphire ingots in the tungsten crucible: preheat with hydrogen peroxide, soak the inside of the crucible with hydrogen peroxide, take the stuck crystal ingots in the tungsten crucible, and conduct subsequent treatment with the tungsten crucible.
The tungsten crucible is the core component of sapphire single crystal growth furnace, which is widely used in the blue gem growth crystal industry. The waist of the tungsten crucible will be deformed under the high temperature working for a long time. When the waist of the crucible is deformed to a certain extent, the sapphire ingots are easily stuck in the deformed place of the tungsten crucible and cannot be safely removed.
In addition, tungsten crucible and sapphire crystal ingots are both very hard and brittle materials, so they are prone to brittle cracks when squeezed. Therefore, it requires four steps to extract the stuck sapphire ingots in the tungsten crucible: preheat with hydrogen peroxide, soak the inside of the crucible with hydrogen peroxide, take the stuck crystal ingots in the tungsten crucible, and conduct subsequent treatment with the tungsten crucible.
The first step is to preheat the hydrogen peroxide, pour the industrial pure hydrogen peroxide or analytical pure hydrogen peroxide into a beaker, and put it on the electric furnace for heating, heating to 50-70℃. The heated hydrogen peroxide is then poured continuously into the tungsten crucible, and the ingots are soaked in the hydrogen peroxide where they are stuck. After six to eight hours, if the hydrogen peroxide is yellowish-green and no bubbles appear on the surface of the liquid, the solution can be poured out, and then the hydrogen peroxide can be poured into the tungsten crucible again and again for three or four times. After pouring, bind the stuck ingots in the crucible with copper braid, and remove the stuck ingots with the help of moving stacking carts and chains. The inner wall of the tungsten crucible was processed by car after the stuck ingots were taken out, to perfect the deformed parts of the tungsten crucible and prevent the ingots from getting stuck again.
In addition to the above methods, the most commonly used extraction method is mechanical grinding. By manually grinding the deformed parts of the tungsten crucible with an alloy or ceramic tool, the inner diameter of the waist of the tungsten crucible is enlarged, and the ingot of the stuck crystal is finally removed. It would be very wasteful to knock the tungsten crucible to take out the stuck ingots.
Stanford Advanced Materials supplies high-quality tungsten products, including tungsten crucible, tungsten powder, tungsten wire, etc. to meet our customers' R&D and production needs. Please visit http://www.samaterials.com for more information.