Benefits Cement Sector
- Optimize the dosage. Cost savings in raw material.
- Avoid and/or reduce blockages in cyclones. Reduced clinker losses.
- Optimize operating conditions of the kiln. Energy saving.
- Control cement grinding (cold start of the mill).
- Quality control of fillers and additions (limestones, blast furnace slags, fly ashes, natural pozzolans, etc.).
- Influence of secondary/alternative fuels in the process.
- Reuse materials from the electrofilters.
- Predict final performance (setting time, mechanical resistance, etc).
THE BENEFITS THAT XRD CAN BRING TO THE CEMENT SECTOR ARE
Cost savings in raw material
Through the quality control of raw materials by X-ray diffraction, it is possible to know their mineralogy and obtain a correct dosage of them. This can provide a saving of material and consequently a saving of costs.
Some of the analyses that can be carried out for the raw materials control are:
– Determination of limestone purity: through the quantification of different carbonates (calcite, aragonite, dolomite, magnesite, ankerite, siderite, huntite, etc.), and the identification and quantification of impurities such as pyrite.
– Determination of sulphate source purity: through the quantification of different sulphate sources (gypsum, anhydrite and basanite) that can affect differently the setting-time, the identification and quantification of other sulphates, for example, celestine, and the identification and quantification of impurities, for example, quartz, dolomite or feldspars.
Avoid and/or reduce blockages in cyclones.
Through the XRD monitoring of the mineralogical composition of the hot meal, the formation of phases that cause blockages / accumulations in the cyclones can be studied. With this, you can reach a balanced proportion of elements in the hot meal that reduces the number of accumulations. This reduction of cyclone blockages therefore reduces the loss of clinker associated with them.
Optimize operating conditions of the kiln.
Through the XRD monitoring of the mineralogical composition of the clinker, it is possible to monitor the relationship of the different phases of the clinker, as well as its polymorphisms. This can detect possible anomalies in the operation of the same, as well as the quality of the clinker.
It is possible to optimize the temperature of the kiln cooking zone (BZT = burning zone temperature), using the alite values determined by XRD.
Information from minor phases such as quartz and free lime: incomplete reactions in the kiln.
Moreover, the presence of some phases can give problems in the finished product, such as:
Free lime and periclase: expansion problems.
Alkaline sulphates: influence on setting properties.
Ferrite phase XRD study can give information about the clinker cooling, which is also important to understand the reactivity of cements at early ages.
Cold start of the mill.
The cement grinding process can be optimized by XRD by monitoring the evolution of the gypsum / basanite / anhydrite content in the mill.
On the other hand, the influence of the grinding additives in the particle size can be studied by means of XRD.
Por otra parte se puede estudiar la influencia de los aditivos de molienda en el tamaño de partícula mediante DRX.
Limestones, blast furnace slags, fly ashes, natural pozzolans, etc.
By XRD it is possible to carry out, not only the quantification of crystalline phases, but also of amorphous phase. This is useful in the characterization of ashes and slag additions since they are the main source of chemical reactivity and therefore of the improvements in the final performances.
Within the quality control of fillers it is important to highlight the monitoring of respirable silica dust.
The use of alternative fuels can incorporate new elements (P, Zn, Cl, etc.) that stabilize different polymorphs in the clinker. New minor phases may also appear in the clinker. Therefore, monitoring all the mineralogical phases of the clinker can help the correct use of these alternative fuels and help to obtain clinkers with reproducible properties.
Reuse materials from the electrofilters.
Elemental and mineralogical composition of the material that is collected in the electrofilters must be known for its correct reincorporation into the production process. In some countries the use of any powder used as a cement additive (< 5 %wt) requires a detailed analysis of the mineral composition.
A daily follow-up of samples, through different characterization techniques, makes it possible to carry out an adequate correlation between composition and final properties of the material.