Historia Contemporanea De Venezuela

Reprint of

September 2007:

Creative Grinding Solutions
by Philippe Jost and Jorg M. Schrabback

Sika Services AG, Tüffenwies 16, CH-8048 Zürich, Switzerland Phone +41 44 436 4040, Fax +41 44 436 4150, www.sika.com

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ADDITIVES/IMPROVERS

I Creative grinding solutions
by Philippe Jost and Jorg M Schrabback, Sika Services AG, Switzerland/Germany

The use of chemicalprocessing agents in the manufacture of cement is well known and state-of-the-art today. The latest developments in the chemical industry have opened new possibilities to further improve the cost structure. Sika has introduced a new approach to the grinding aid business. The brand SikaGrind stands for new creative solutions for grinding aids and performance enhancers.

I

n the mid-1930s, cementplants started to use cement additives to increase the production volume of cement. It became evident, that the use of cement additives enabled producers to achieve cement fineness and qualities which would hardly be possible without them. The basic raw materials used then were amines, amino-acetates, glycols and gluconates. In the last decades, the main focus was to find new and more efficient aminesconcerning grindability and hydration-enhancement.

New technology
Sika has now developed a new raw material with excellent properties in terms of improved grindability. The
Figure 1: total feed of cement mill consisting of fresh material, the return from the separator and SikaGrind

SikaGrind® Technology
The brand SikaGrind® stands for cement grinding aids which are developed to improvethe production rates of ball mills and increase the separator efficiency. As a joint effect, the grinding installation produces more tonnes per hour and leads to cost savings due to a lower relative power consumption per ton of cement. Sika offers various types of products, from basic grinding aids which achieve a constant production on higher output-level to special grinding aids with additionalquality enhancing properties like impoved strength, accurate air entrainment and adjustment of cement powder flowability.

latest generation of SikaGrind® cement additives is based on polycarboxylate (PCE) polymers. These products allow for a consistent production at the highest production rates. The special ViscoCrete polymers have been developed in Sika’s central R&D laboratory in Zürich,Production [tph]
95 90 85 80 75 70 65 60 55 50 45

Switzerland and are produced worldwide by all Sika’s polymer-production plants. The PCE polymers, which look similar at the molecular level to amines and glycols, and contain similar ionic groups are quickly distributed to their field of action due to the excellent mixing behaviour of the mill.
Energy [kWh/t
90
60

85 80 50.2 47.3 44.7

5550

45

40

35

Figure 2: adjustable mill output related to the dosage of SikaGrind®-800

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0.018% SikaGrind

0.035% SikaGrind

ICR SEPTEMBER 2007

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ADDITIVES/IMPROVERS

Production
40 35 30 25
Production (tons/h) Blaine (cm²/g) 34 4077 4000 +/- 100
cm²/g target Blaine

Blaine
40 36 4117

4400

grinding conditions (see Figure 1).

Production +18%
3840

Products developed out of these new PCE polymers Production 20 3600 + 6% include the new SikaGrind®-800 15 Series. These new 10 3200 products respond Strength increase 0.05% Glycol 0.03% SikaGrind 0.03% SikaGrind very well to ball mill Another of the plant trials was set the optimised systems. Cement target to increase the slag content at a Figure 3: increased mill efficiency withSikaGrind®-800 technology output could be constant production rate, in this case of easily increased. The a CEM II/B-S 32.5 R (Blaine 3100cm²/ The easy dispersable PCE polymers higher the dosage, the more production g). Sika’s new grinding aid technology support cracking behaviour of the cement gain could be achieved (Figure 2). This allowed for the production of a cement particles by direct contact...