|
|
|
|
|
Question:
We are using a small ball mill to process a ceramic slurry. Our target is 90% less than 7 microns without metal contamination.
Answer:
All of the mills CB Mills sells are continue process small media mills. These are available in a variety of wetted contact parts including ceramic. Our standard ceramic materials of construction are YTZ, ZTA, and SiSiC. These machines are available in one piece mill vessel construction. By selecting the correct media, we certainly can use our horizontal small media mill to produce you required slurry from batch sizes of 100 ml and larger. Please contact us for more details.
Question:
We are using a large production shot mill. When we first load the shot mill with steel shot, the shot mill motor draws high amps. What is wrong?
Answer:
Steel shot mills will draw high main drive motor power when load with steel shot if they are not also charged with a lubricating liquid. This can be a light oil or resin blend. This provides a small amount of lubrication in the shot mill chamber, reducing power requirements.
Question:
Please provide a quotation for one agitator bead mill to be used in our production plant for the dispersion of paints. The final output of the machine must produce a fineness of grind to a 7+ Hegman.
Answer:
Unfortunately it is difficult for us to provide an agitator bead mill quotation based on the information provided. To accurately provide a quotation, we will require the starting particle size, the target particle size, density of the slurry, inlet temperature of the slurry, maximum temperature of the slurry, viscosity and volume required. Also, any solvents that may be used.
Question:
Please provide a quotation for a submerged mill to be used to produce our general industrial coatings. Our batch sizes are 100 – 500 gallons.
Answer:
Unfortunately CB Mills does not offer submerged mills. We can provide high flow / high energy mills for recirculation milling. By using as high flow recirculation mill, we can provide further benefits:
1) We eliminate the need jacketed tanks to maintain product temperatures. When using a submerged mill, heat is developed. This heat cannot be dissipated with the cooling available in the mill head alone. Supplemental cooling (jacketed tanks) is required.
2) Batch vessel geometry is critical to successfully operate a submerged mill. Submerged mills are in fact high energy recirculation mills. The key to their success it to have the batch flow through the milling head as many times as possible. Unless vessel geometry is maintained, dead zones in the batch vessel will occur. Using a high energy high flow recirculation mill eliminates this requirement.
3) High flow recirculation mills can be used for circulation milling or the can be used as high energy mills for batch operation.
4) High flow recirculation mills can use a wider variety of grinding media. This allows greater flexibility and range to further optimize mill performance.
5) High energy mills can process a wider range of product viscosities and densities than submerged mills. Submerged mills circulate the batch by using specifically designed impellers to promote flow within the vessel. These impellers can be either close coupled to the milling shaft or independent. In the case of thicker materials, auxiliary sweep type systems must be employed to promote flow back to the mill head. High energy recirculation mills can viscous materials. Generally, as long as the material can be pumped it can be processed in a high energy recirculation mill.
6) Cleaning a submerged mill required manual labor. Generally, the sub mill can be cleaned by first soaking the mill head in a cleaning dip tank to remove most of the contamination. A further manual cleaning is required to clean areas of the mill head that are not cleaned during the dip tank cleaning thereby exposing operators to wash solvent vapors and splashing of harsh chemicals. Areas that do need manual cleaning are the stabilizing rods and external sections of the mill head. While these areas are visible, they will and do require cleaning. High energy mills can be cleaned easily with little of no operator exposure. Additionally, by keeping the feed and discharge hose as shot as practical, cleaning of the mills can use less than three mill volumes to prepare the system for the next batch. With our high energy recirculation mill, this can be as little as 12 liters of wash.
Question:
We are using a large production vertical media mill. We are using a standard charge of 1.0-1.4mm zirconium silicate. The screen becomes plugged with dried product and eventually the mill overflows. How can we prevent this?
Answer:
There are a number of issues that can cause the problems outlined above with vertical media mills. Screen blinding is typically caused by poor quality grinding media. The solution for this is to purchase better quality grinding media. This is absolutely critical when filling the vertical media mill with a new charge of media. Broken media becomes lodged into the screen slots. Once the broken pieces get pushed into the screen, they are difficult if not impossible to remove. The second cause of screen blinding can be caused by product drying on the mill screen. This can be eliminated by installing the provide screen covers (fume guards) to help keep the screen area wet. It is important that after the batch the screen area should be washed and brushed down to further prevent screen blinding.
|
|
|
|