Cement and concrete analysis

When selecting raw materials, manufacturers need to keep costs minimal, while ensuring that the materials are compatible with cement production. Especially when using alternative raw materials. Next to the costs of the materials also their impact on the process efficiency and the sustainability challenging targets (2050 Net Zero) must be considered. For this, chemical and mineralogical composition are crucial.

Our solutions help to minimize scrap and to optimize the mineralogical and chemical compositions of raw materials by providing high frequency analysis of raw material components, specifically when automated. They can do this both at the quarry and in raw mix proportioning. By providing results quickly, these instruments enable producers to reduce waste from sampling and ensure a stable kiln feed for energy efficiency in the remaining process (pre-homogenization and proportioning).

When it comes to raw mix processing, maximizing kiln efficiency is an essential part of reducing energy consumption, emissions, and maintenance requirements. Optimizing the materials that enter the kiln can help achieve this: the two main points of attention are monitoring the correct and stable mix chemistry and getting the proper raw grinding. 

Stable raw meal composition is also essential to ensuring consistent heat profiles in the kiln and delivering a high-quality end product with the right properties such as compressive strength. It also impacts energy consumption, grinding additive use, refractory life, additive consumption, fuel demand and other process factors. As an example, kiln oxidizing conditions are mandatory to avoid the decomposition of Alite C3S to Belite C2S and free lime. This stability can be achieved by controlling the chemical composition using XRF or on-line elemental analysis such as Neutron-Activated Cross-Belt analyzers, or by controlling mineralogy using XRD.

Optimal operating requirements are also to work with fine raw meal (avoid specifically coarse calcite and quartz grains): raw mix particles must be fine enough to ensure that they can mix and be ground well without hard burning. Then laser diffraction for particle size analysis can help ensure this. 

WROXI Module

Certified Reference Materials-based solution for the determination of oxides by XRF in a wide range of materials.

WROXI is a synthetic, high-quality Certified Reference Materials (CRM) kit that covers a wide range of oxide materials such as ores, rocks, and geological materials. It has a dual purpose: either for primary fusion glass disk calibration, or to develop secondary pressed powder calibrations.

The beads-based WROXI-CRM base software package consists of 15 Certified Reference Materials, application templates and monitoring samples. Once completed with the WROXI-CRM Cement extension (9 additional CRMs), it becomes an off-the-shelf solution for primary and secondary element analysis in various raw materials, raw meal, clinker and cement samples.

Increasingly, alternative fuels in the form of biomass, mixed fuels, or fossil waste with lower emissions factors are replacing resource intensive fossil fuels. By recovering the calorific value of fuel waste, these additive fuels help to reduce emissions from cement production. 

But alternative fuels must be fully characterized for their safety, chemical, thermal, and physical properties to assess their effect on parameters such as flame temperature and heat exchange.

Our elemental analyzers (X-Ray Fluorescence and Cross-Belt CNA), mineralogical X-Ray diffractometers, and automatic fusion sample machines make this easier.

Clinker production results from Pyroprocessing: raw meal preheating, calcination clinkerization, clinker cooling, crushing. To achieve the right cement properties, as seen above, the proper calcination conditions have to be controlled, followed by a rapid quench of the clinker.

Attention is then on controlling the proper calcination (free lime), avoiding unwanted elements and maximizing positive mineral phases for the targeted properties of the cement. 

To ensure proper calcination and the right clinker mineralogy, X-Ray diffraction is the best analytical analyzer: it allows to quantify C3S content and type that influences strength development, C3A content and type that impacts fresh properties, and amount of free lime and periclase that should not be higher than targeted limits. Malvern Panalytical’s analytical solutions support this monitoring using the Aeris XRD compact diffractometer. 

Unwanted elements are controlled using X-Ray Fluorescence, in internal recycle streams from fuels or raw mix. Both the Zetium and the Epsilon 4 give the required data to monitor this very efficiently.

Finally, as seen above, in a sustainable approach, manufacturers target not only the high quality of clinker but also want to save energy and resources. Pyro processing of clinker needs calcination at 1450 °C and related energy is usually satisfied by firing coal at calciner and kiln main burner. To save energy and decrease CO₂ emissions, waste and biomass are used as alternative fuels more and more. Alternative Raw materials are also used. Dosages of such Alternative Fuels or Alternative Raw Materials require some specific controls to avoid negative effects on the clinker reactivity. Our X-Ray solutions enable you to enjoy the benefits of alternative solutions for clinker production without worries about the impact on quality.

Cement is produced by grinding clinker with different active ingredients (SCMs) into a fine powder to achieve the desired properties of cement. The most common additions are gypsum and mixed materials such as fly ash, blast-furnace slag, limestone filler, natural pozzolans and calcinated clays. They are ground to the required fineness and the right proportions to targeted crystalline cement phases. 

To reduce energy consumption, over-grinding must be minimized. The granularity of the finished cement affects its rate of hydration reaction, as well as the amount of water, retardant, and dispersant needed, and is a key factor in determining the strength of the cement. Our particle sizing solutions can help to achieve optimum cement granularity. Thanks to their fast, real-time analysis including in the challenging process environment, they allow producers to react quickly to any anomalies and monitor ambitious accurate targets. In this way, they help enable significant energy savings and optimal short-term and long-term cement strengths. What’s more, they can be quickly and easily installed for minimal disruption.

Monitoring of Sulphate content and mineralogical composition type (linked to dehydration during grinding) are crucial for achieving the right fresh and hardened cement properties. Regarding blended cement, closely controlling composition (including amorphous materials) is required to meet clients’ specifications and CO₂ emissions targets. Our X-Ray fluorescence and X-Ray diffraction instruments are of great help for this.

Concrete is made up of three basic components: water, aggregate (rock, sand, or gravel) and cement. Cement, usually in powder form, acts as a binding agent when mixed with water and aggregates. This combination, or concrete mix, will be poured and will harden into the durable material with which we are all familiar.

Concrete recycling is becoming an increasingly popular way to utilize aggregate left behind when structures or roadways are demolished. In the past, this rubble was disposed of in landfills, but with more attention being paid to environmental concerns, concrete recycling allows reuse of the rubble while also keeping construction costs down.

In both cases, the main attention is that the concrete meets the promised workability, qualities once hardened (resistance to freezing, water tightness, wear resistance, strength), and the price of use (water quantity).

Composition and material sizes are again of great importance. Our laser or X-Ray based instruments provide the required information for a high-quality check of such characteristics.