The term bulk material analyzer is the generic noun for that device which fits around a

conveyor belt A conveyor belt is the carrying medium of a belt conveyor system (often shortened to belt conveyor). A belt conveyor system is one of many types of conveyor systems. A belt conveyor system consists of two or more pulleys (sometimes referred to ...

and conducts real-time elemental analysis of the material on the belt. Other names often found for such a device include ''belt analyzer'', ''crossbelt analyzer'' and ''elemental analyzer''. This product first found popularity in the

cement A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate) together. Cement mix ...

industry during the 1990s, and today most new cement plants include at least one analyzer, if not two.

Cement industry

A couple of applications predominate for the bulk material analyzer in

production.

Stockpile management

One is known as "stockpile management," whereby an analyzer located upstream of the pile is able to track the cumulative chemistry of the pile. This allows the operator to direct haul

truck A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction ...

s to different sections of the

quarry A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to reduce their envi ...

in a way that will result in the final elemental composition of the pile close to target.

Raw mix proportioning

A second application in cement for the bulk material analyzer is raw mix proportioning. An analyzer placed just upstream of the raw mill can monitor the chemistry of the raw mix and automatically trigger an adjustment in the proportions of the reclaimed stockpile and the correctives. By doing so, the plant is able to reduce the variability in the raw mix, and later on the

kiln A kiln is a thermally insulated chamber, a type of oven, that produces temperatures sufficient to complete some process, such as hardening, drying, or chemical changes. Kilns have been used for millennia to turn objects made from clay int ...

feed. Consistent kiln feed chemistry in turn leads to lower fuel consumption per ton of clinker produced.

Other applications

In the 2000s the application of the bulk material analyzer was extended to include

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...

s. Today, analyzers are found in

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

iron ore Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the fo ...

, and

phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phospho ...

s, to name a few. One of the advantages of these analyzers is the timeliness of information for the user. Another is the avoidance of physical sampling.

Technology

The technology most frequently found in bulk material analysis and coal analysis are PFTNA (Pulsed Fast Thermal Neutron Activation), the

prompt gamma neutron activation analysis Prompt-gamma neutron activation analysis (PGAA) is a very widely applicable technique for determining the presence and amount of many elements simultaneously in samples ranging in size from micrograms to many grams. It is a non-destructive method, ...

(PGNAA) and Laser-induced breakdown spectroscopy (

LIBS Laser-induced breakdown spectroscopy (LIBS) is a type of atomic emission spectroscopy which uses a highly energetic laser pulse as the excitation source. The laser is focused to form a plasma, which atomizes and excites samples. The formation of ...

). PFTNA and PGNAA technology rely on activation of the material on the conveyor belt by

neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons beh ...

s, and the instantaneous emission of

gamma ray A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...

s from nuclei which have absorbed neutrons. Capitalizing on the unique gamma ray spectrum associated with each element, the instrument can perform an analysis each minute on the composite spectrum to determine the overall elemental composition of the material. LIBS operate by focusing the laser onto a small area at the surface of the material forming a

plasma Plasma or plasm may refer to: Science * Plasma (physics), one of the four fundamental states of matter * Plasma (mineral), a green translucent silica mineral * Quark–gluon plasma, a state of matter in quantum chromodynamics Biology * Blood pla ...

plume. When plasma quickly cools down the atomic emission lines of the elements can be observed using

optical spectrometer An optical spectrometer (spectrophotometer, spectrograph or spectroscope) is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify mate ...

. Based on obtained spectra quantitative chemical analysis of the sample is performed.

References

* Alsop, Philip A.; Chen, Hung, Tseng, Herman. “Prompt gamma neutron activation analysis (PGNAA).” ''The Cement Plant Operations Handbook.'' Fifth ed. October 2007. * Berg, Joel L. “High Frequency Blend Control.” ''World Cement.'' March 1999. * Bond, J.E.; Coursaux, R.; Worthington, R.L. "Blending systems and control technologies for cement raw materials " Industry Applications Magazine, IEEE Nov/Dec 2000 Volume: 6 Issue:6 page: 49 - 59 * Bond, J.E.; Wintz, S. "Blending and control systems technologies for cement raw materials revisited - PGNA analyzer application review - An example from Lafarge's Davenport plant in Buffalo, Iowa USA" 53rd Cement Industry Technical Conference, 2011. Conference Record IEEE-IAS/PCA, May 2011, 18 pp. * Hook, Jeff and Darrell Leetham; “CrossBelt at Union Bridge.” ''International Cement Review.'' November 2008. * Foster, S.; Bond, J. "The history and future of nuclear elemental analyzers for product optimization in the cement industry", Cement Industry Technical Conference, 2006. Conference Record. IEEE, 9–14 April 2006, 18 pp. * Proctor, R. J. On-line Prompt Gamma Neutron Activation Analyzers”, ... Handbook, Editor-Gregory K. McMillan, Fifth Edition, McGraw Hill, 1999 * Woodward, Richard. “Transforming Pre-Blending Strategy.” ''World Cement.'' April 1997. * “On-line Analysers.” ''The World Cement Plant & Equipment Handbook.'' Volume 1. 1996. * Michael Gaft, M.; Nagli L. "Industrial Online Raw Materials Analyzer Based on Laser-Induced Breakdown Spectroscopy", Applied Spectroscopy, September 2014 Analytical chemistry