The consumption of aggregates for construction grew by 10.5% in 2017
The consumption of aggregates for construction grew by 10.5% in 2017, to 112 million tons, with signifiant territorial variations and two autonomous communities still in decline. Likewise, aggregate quarries produced 40.8 million tons of industrial aggregates destined to the manufacture of binders, to the ceramic products, to other industrial uses, to the food industry and to export. With these two components, the total business volume reached 703.2 million euros. The companies of the industry directly employ 8,248 workers and 13,321 indirect, for a total of 21,569 workers, the 39,8% of the extractive industry. The number of active aggregates sites is 1,799, the 64% of the total of extractive sites in the country.
Contribution of the aggregate sector to the conservation of the sand martin
The sand martin (Riparia riparia) is a migratory swallow with conservation interest in Europe. Its natural nesting habitats are the slopes of rivers, streams and lakes with newly eroded sandy banks where they dig their burrows. In recent decades, and in extended parts of its global breeding area, the sand martin has increased the use of mining areas (especially aggregate quarries and pits) as nesting areas, where it currently concentrates its main breeding colonies. This represents an opportunity for the aggregate sector to positively contribute to the conservation of a threatened species, as well as to promote local biodiversity.
Admixtures of different size grain limestone rocks, in portland cements with diff erent contents of C3A. Influence on mechanical resistances
The samples have been selected; chemical, mineralogical and petrographic criteria have been marked by X-ray fluorescence, X-ray diffraction and digitalization of thinfilm images respectively.
Once selected the samples of chemical and mineralogical composition very similar but petrographically different are mixed with the portal contents, one of high content in C3A (9,4%) and another of low content in C3A (1,7%), in the following proportions: 5%, 10%, 15% and 20%, performing with these mixtures the tests of mechanical resistance to flexion and compression at 2, 7, 28, 90, 120 and 180 days of mortar specimens according to the UNE- EN 196-1. Cements of origin were also tested to obtain the values and use them as reference.
The results indicate that the behaviour of the limestone rocks is different according to its petrography. The limestone rocks of coarse-grained size (marbles), for that reason of greater reduction factor, obtained higher mechanical resistances than those of fine grain (micrite) walls with a high C3A content. Likewise, these coarsegrained stones can be assimilated as new for the high content of C3A cement.
Modular grinding units Plug&Grind for cement plant upgrades
After recession, the cement industry is changing the business paradigm, searching for scaled ways of growth, controlling risks and avoiding high investments.
Modular grinding stations, Plug&Grind, are an innovative solution that allows cement producers to improve their business intelligence. Plug&Grind in cement industry has had momentum since 2011. This matured technology proven worldwide and improved year over year- is evolving to larger sizes and offering a wide range of possibilities. All the project management stages (engineering, procurement, construction and operation) are being designed into a virtuous retrofit circuit, with the result of standardization.
Standardized Installations are minimizing capex deviations and on site erection costs. Plug&Grind has also introduced the concept of relocatable installations. Having moveable assets, makes the decision taking easier, shortens the time in the market of production facilities and eases financing and permitting.
This technical paper, tries to show the advantages and challenges of this Plug&Grind technology, focusing on its use for cement plant upgrades on 2017- 2018. I will show real case scenarios that illustrate the potentiality of this innovation and real application of this technology.
X-ray diffraction (XRD) and cements: from research to control quality
Building materials are very complex samples of commercial importance. Therefore, quantitative knowledge of their mineralogical composition through X-ray diffraction (XRD) is crucial to optimize the manufacturing process, as well as help to predict the final performances of these materials.
Due to the detected need, in this area, for the characterization of materials through this technology and with the main purpose to apply and transfer the knowledge acquired in the university to the industrial sector X-Ray Data Services (XDS) arise. They are a spin-off company from the University of Malaga (Spain). This technology-based business project provides different services based on X-ray diffraction and adapted to the needs of industrial customers.
Lubrication best practices maximize open gear life
Large open gears on grinding and pulverizing mills present signifi cant lubrication challenges due to the high load, heavy-shock nature of the application and constant exposure to harsh environmental conditions, such as cement, limestone, coal or silica dust.
This article discusses lubrication reliability best practices for open gears including selecting the right lubricant and the right method of application to combat these challenges. Choosing wisely will help protect the gears from wear, increase uptime, and –in most cases– dramatically reduce gear set operating temperatures, lubricant consumption, energy consumption and waste disposal.
Long life the filtration systems!
The optimized operation of the filtration system is directly related to the performance of a cement plant. We cannot leave the installation unattended, although, beyond performing timely maintenance on it, we must be able to anticipate possible incidences, minimize failures, reduce operating errors, and, above all, guarantee the life cycle extension of the system.
AAF-SA Field Services proposal, understood as an evaluation and analytical diagnosis on those elements that integrate the complete installation, brings together different techniques and technologies that allow establishing absolute control over the system in order to avoid future problems that may impact negatively in the normalized operation of the installation.
Windcrete: “spar” type floating monolithic concrete structure for off shore wind turbines
The main challenge of the floating wind turbines is the high construction and installation costs of the substructure, being too expensive for its commercial exploitation in the current energy market. With the aim to achieve a cost-effective floating platform for offshore wind turbines, a new concept of a monolithic floating “spar” buoy named Windcrete is presented. The monolithic concrete structure includes both the tower and the floater, built in a continuous single piece. This new concept offers a significant cost reduction during the construction phase and also in operation because the platform is almost free of maintenance during its lifetime. Main dimensions and properties of the platform are presented, including a basic structural assessment. The construction and installation processes are treated, taking into account the special requirements of the monolithic design. Finally, a cost comparison between a steel and a concrete equivalent platform designs has been performed, obtaining a material cost reduction larger than 60% in the case of the concrete design. Then, the scalability of the concept through the main dimensions and construction costs for turbines of 6, 8 and 10 MW is presented. Finally, a cost comparison when using different ballast materials for Windcrete highlights the interest of using the cheapest possible material despite having a smaller bulk density.
Applications of the iron silicate produced in the copper concentrate fusion step
Iron silicate is a material obtained from the metallurgical slag produced in the electrical furnace used within the copper production process. This is produced in the copper concentrate fusion step when silica in added as flux to separate the iron from the sandgrouse. The aim of this study is the chemical and physical characterization of the iron silicate and its assessment to be used to adjust the iron composition in the production of portland cement clinker, as abrasive agent and as filler in hydraulic engineering works. Chemical and physical methods used in the present paper have been: XRF and wet process, according to EN 196-2, chemical composition; testing methods for non-metallic abrasives according to ISO 11127; iron silicate granulometric analyses according to EN 933-1. Finally, filling capability of the iron silicate was assessed by using the harmonized European standard EN 13242.
It has been observed a low water solubility of the trace elements presented in the matrix of this material. Comparing two portland cement clinkers, the first one made without iron silicate and the second one produced using iron silicate, it has been determined that the chemical composition was not significantly modified by using iron silicate as flux.
In conclusion, it could be said that the iron silicate can be used in the portland cement clinker production, to replace abrasive agents within the metallic surface preparation process and to replace natural filling materials.
Sustainable solutions for recycling pavements and stabilization of soils with hydraulic road binders (HRB)
The current regulations allow the use of hydraulic binders (HRB) designed for use in the recycling of pavements and in the stabilization of almost all the existing soils in the trace in a single treatment.
The properties of the HRB off er an efficient and sustainable alternative in recycling projects when there is evidence of the heterogeneity of the pavement to be rehabilitated, such as rural roads or when reusing materials substitutes for natural aggregates, providing greater benefi ts to the new pavement. Recycling in situ with cement is an alternative for exhausted roads, with which it is sought to convert a firm into a homogeneous structure adapted to the traffic it must support. The recycling of these pavements with cement makes it possible to take advantage of these deteriorated layers.
Previous experiences have also shown that they will achieve a more durable firmness together, more resistant to water and erosion.