CGB-Lab test 2 ( Screen residue & Homogeneity )
As CGB technology has increasingly caught the eyes of the global cement industry thanks to its remarkable performance in power saving,we’d like to share the lab test a couple years ago ( 2016 ) in China, which gives better picture on how to put this new technology into use properly after replacing steel ball.
φ700mm×700mm Lab Batch mill
It is equiped with torquemeter that can read the power consumption directly.Below is the technical parameter tables:
|1||Mill Shell Dimension|
φ700×700mm （Effective. 600×600mm）
XW‐6‐35 Raito:( 29：1)
2. Clinker and FGD gypsum
Literally minimum 2 raw materials shall be used. However in order to avoid deviation due to heterogeneous mixture , one-component clinker was applied as raw materials during the test. When it came to the cement quality test, ground FGD ( Fuel Gas Desulfurization)gypsum is blended for various performance test.The technical data of the raw materials are as follow:
FGD gypsum blaine:
3. Mill loading rate ( CGB -ceramic ball Vs steel ball)
During the test, both CGB and steel balls were set with loading rate at 24% with media scheme as below: ( steel balls=174kgs,CGB= 84kgs, clinker charge=20kg/ each time)
4. Cement product screen residue comparison:
Below chart demonstrate screen residue variation curve under different rotation rate and blaines:
With steel balls as grinding media,the screen residue are nearly the same given same blaine target despite of various rotation rates.However, when CGB serves as grinding media,the screen residue will vary against the rotation rate.The higher rotation speed, the higher screen residue figure.As above chart comparison suggest: under same blaine, CGB witness 4% drop than steel balls at R45um.And at R80um, it’s around 1% drop.
5.Cement product homegeneity coefficient comparison:
Below chart show : when steel balls serve as grinding media, at different rotation rate whereas different blaines (3200cm2/g & 3500cm2/g ) how the grain distribution curve and homogeneity appear.
Blaine @ 3200cm2/g
Blaine @ 3500cm2/g
As above chart show, when steel balls serve as grinding media, at same blaine, the grain distribution of cement product nearly don’t change against the variation of rotation speed. The n value stay at 0.87~0.91。
Below chart show : when CGB serve as grinding media, at different rotation rate whereas same blaine (3200cm2/g ) how the particle distribution curve and homogeneity appear.
Blaine @ 3200cm2/g
As above chart show, when CGB serve as grinding media, at same blaine, the grain distribution of cement product change against the variation of rotation speed. When the rotation speed is high, it appears wide, otherwise it goes narrow. The n value stay at 0.89~0.97.
Given same blaine, the homogeneity coefficient of CGB application after replacing steel balls see a little bit variation. It suggests that the grain distribution grow narrow.Meanwhile, the screen residue of cement product also decline.
The rotation rate doesn’t impact steel ball grinding performance too much.But it will more or less do to CGB application.When the rotation speed is high,the grain distribution is narrow while when the speed is low,the grain distribution grow wide.
In next article introducing lab test serie-3, we are going to share the comparison between various grinding media on cement product fluidity and 28D strength.