Laboratory Report 29/2010 on grinding tests in the Loesche-Technical Center Neuss with the following samples:
Date:
21.04.2010
LZ-No.:
4939
Code:
Rawan Line 2 RM
Client:
Grasim Industries Ltd.
Project-No.:
IN_9937
Contents: - Explanations on Loesche grinding tests - Grinding test MV 6982 dated 07.04.2010 - Description of sample LZ 4939 / 8
Laboratory mill LM3.6
Page 1
Grinding test with LOESCHE Mill LM 3.6 Description of the grinding test plant: LOESCHE- grindings tests are carried out in a LOESCHE Mill type LM 3.6. This vertical roller mill is equipped with 2 rollers and the classifier is mounted on top of the mill. The feed material is fed directly with a screw conveyor onto the grinding table, where it is taken under the rollers for comminution. The ground material is pneumatically conveyed by the air flow leaving the louvre ring up to the classifier, where the finish product is separated from the grits. The air flow is heated with a gas fired hot gas generator for the required heat for the drying process. The rejected grits fall back from the classifier down onto the grinding table and the finished product is conveyed to a jet pulse filter. The separated product is conveyed into a hopper, which is located on a scale for determination of the mass flow. On top of the hopper a representative sample of the finished product can be taken. The clean gas behind the filter is sucked by the mill fan and streams out of the stack. A partial air flow can be recirculated to decrease the amount of required heat for the drying process.
page 2
Description of a LOESCHE standard grinding test: Standard- grinding tests are always carried out with identical mill- and classifier geometry. The moisture of the feed material must be < 6% by mass and the maximum particle size is 15 mm. To achieve this the samples are dried and crushed before the grinding test. According to the type of feed material certain set values for the grinding pressure, grinding table speed, air volume flow and temperature after mill are kept constant during the whole grinding test. As the only variable, the classifier speed will be changed at certain intervals to vary the fineness of the finish product. At a constant classifier speed a product of constant fineness is produced. After each change of the classifier speed the mill system is running for a certain time until stable conditions in the circuit can be achieved. During the production of a specific amount of product a representative sample of the product is taken and the mill throughput is measured. At the same time all the operational data including the specific power consumption are recorded. The particle size distribution and/or the mass related surface area during the period of measurement are analysed. In the grinding rollers wear plate inserts are installed. The weight loss of the wear plates during the grinding test indicate the abrasive properties of the ground material.
Results of grinding tests: A standard grinding test leads to the following results: 1. LOESCHE- Grindability Factor MF for cement raw material (without dimension): MF = measured product mass flow at 15% R 0,09mm / nominal product mass flow of the LM 3,6 This formula is related to standard grinding conditions for the ground material, the mill LM3,6 and the mill adjustments. 2. LOESCHE- Load Factor LF (without dimension): LF = measured product mass flow / nominal product mass flow of the LM 3,6 The Load Factor LF for clinker and blast furnace slag grinding tests is related to a mass related surface area of 3300 cm²/g acc. to Blaine. For coal grinding tests LF is related to 15% R 0,09mm. 3. Specific power consumption [kWh/t]: The specific power consumption is related to the product mass flow and is calculated with the measured torque at the grinding table and the actual grinding table speed. The specific power consumption is related to the shaft of the mill gear box without any losses or corrections. 4. LOESCHE- Wear Factor vp (without dimension): The Wear Factor vp is calculated with the weight loss of wear plates in the grinding rollers and indicates the abrasive properties of the ground material.
5. CaCO3 content [m-%] (only for cement raw material) In order to assess the nature of the feed material samples are taken of the ground product and the remaining material on the grinding table. The content of CaCO3 is determined by means of titration. 6. Quartz content [m-%] (only for cement raw material under occurence of high wear) During the grinding test it is possible that harder components of the feed material (mainly quartz) accumulate on the grinding table. In order to predict possible influences on wear and mill performance, samples of the ground product and the remaining material on the grinding table are compared to determine their content of quartz, when is insoluble in phosphoric acid. 7. Grindability acc. to Hardgrove [°H] (only for coal) The grindability acc. to Hardgrove is determined according to DIN 51742 or ASTM D 409.
page 3
Code: Rawan Line 2 RM
MV 6982
Date of test: 07.04.2010 Grinding test performed by: Heisinger
Delivery: LZ- No.:
4939
Client:
Grasim Industries Ltd.
Date of delivery:
31.03.2010
Name of grinding test / mixture:
Standard Grinding Test CRM
Feed material: LZ-/SampleNo.: 4939 / 8
Moisture:
Designation of sample: Limestone
on Delivery
Mill Feed
0,22 %
as delivered
Composition 100 %
Grinding test results: P spec.
related to:
MF = 0,62
8,8 kWh/t
15 % R 90
µ
m
LF = 0,64
8,5 kWh/t
19 % R 90
µ
m
Wear factor vp: 0,015 Content of quartz in product:
n. meas.
ontent of quartz on grinding table:
n. meas.
CaCO3 content in product: 71,5 % CaCO3 content on grinding table:
n. meas.
Grinding test plant: Laboratory mill: Dam ring height:
LM3,6/1 7 mm
Mill adjustment: Cement raw material Type of classifier: LKS
Remarks: All values are laboratory results which have to be transformed into operating values regarding the plant configuration!
Page 4
LZ 4939 Date of delivery:
Code:
Rawan Line 2 RM
Client:
Grasim Industries Ltd.
31.03.2010
LZ-/Sample-No.: 4939/8
Limestone
Author:
Description of sample: Type of sample: Limestone Particle size range:
0 to:
150 mm
Type of material: solid rock; with fines; Properties:
easy to convey;
Shape:
lumps; irregularily (shaped);
Colours:
(Acc. to Munsell Soil Color Charts 1998)
Colour 1: Colour 2: Edges:
edged;
Structure:
dense;
Sample after soaking 24h in water:
unchanged;
5Y 5/1
gray
at
90 %
5Y 7/1
light gray
at
10 %
oistures determined at: 105°C
Moisture: on delivery: 0,22 %
Surface moisture: not measured
Hygroscopic moisture: Max. water absorption: not measured
1,51 %
Page 5
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