The conventional cement grinding system, the ball mill, has very poor
efficiencies in spite of innovative improvements. For this purpose, development
of new techniques, which allow proper size reduction and uniform particle size
distribution with less specific energy consumptions, have become a necessity.
The aim of this study is to make a comparative analysis of the fairly new cement
grinding technologies, COMFLEX® / Grinding System, Roller Press and
HOROMILL® / , at the same cement production plant with the same raw materials.
In this context, CEM I 42.5 R type cement was produced with a fixed Blaine
fineness of 3600 (± / 100) cm2/g at three different grinding units. The same raw
materials, clinker and gypsum, and identical feeding ratios, 95% and 5%, were
used to produce cement. Accordingly, these different grinding techniques were
inspected with respect to the microstructural properties of cement particles, and
the relative chemical, physical and mechanical properties of products.
It was found that the main cement grinding parameters, specific surface area
and sieve residue, do not show expected relation and change with each grinding
system due to differences in the size reduction technique. Moreover, strength
and other hardened mortar properties are directly affected by the liberation
conditions of reactive grains at grinding stages.High capacity and low specific energy consumption i.e. the breaking and cracking
efficiency of the roller press and higher grinding performance of the ball mill
promoted the COMFLEX® / system. On the other hand, the roller press was clearly
advantageous at early strength performances with moderate specific energy
usages during grinding. Nonetheless, it also had drawbacks like higher water
demand and earlier setting times (which mean higher hydration temperatures).
When the wideness and sharpness of classification results were considered,
HOROMILL® / gave better results with high circulation and efficient air
classification design / although there were weaknesses of the system such as
lower capacity and higher specific energy consumption rate.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12612997/index.pdf |
| Date | 01 February 2011 |
| Creators | Fidan, Berkan |
| Contributors | Hosten, Cetin |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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