Effect of Processed Volcanic Ash as Active Mineral Addition for Cement Manufacture

Abstract

In the last quarter of 2021, there was a very significant eruption of the Cumbre Vieja volcano on the island of La Palma, belonging to the Canary Islands, Spain. It generated a large amount of pyroclastic volcanic materials, which must be studied for their possible applicability. This work studies the properties and applicability of the lava and volcanic ash generated in this process. The need for reconstruction of the areas of the island that suffered from this environmental catastrophe is considered in this study from the point of view of the valuation of the waste generated. For this purpose, the possibility of using the fine fraction of ashes and lava as a supplementary cement material (SCM) in the manufacture of cement is investigated. The volcanic material showed a chemical composition and atomic structure suitable for replacing clinker in the manufacture of Portland cement. In this study, the cementing and pozzolanic reaction characteristics of unprocessed volcanic materials and those processed by crushing procedures are analysed. To evaluate the cementitious potential by analysing the mechanical behaviour, a comparison with other types of mineral additions (fly ash, silica fume, and limestone filler) commonly used in cement manufacture or previously studied was carried out. The results of this study show that volcanic materials are feasible to be used in the manufacture of cement, with up to a 22% increase in pozzolanicity from 28 to 90 days, showing the high potential as a long-term supplementary cementitious material in cement manufacturing, though it is necessary to carry out crushing processes that improve their pozzolanic behaviour.

Volcanic Ash from the Island of La Palma, Spain: An Experimental Study to Establish Their Properties as Pozzolans

“…These results are not in concordance with the results published by Rosales et al [19], in which pozzolanicity values above the solubility isotherm are obtained. This difference may be likely due to the difference in the specific surface area of the ashes employed as These results are not in concordance with the results published by Rosales et al [19], in which pozzolanicity values above the solubility isotherm are obtained. This difference may be likely due to the difference in the specific surface area of the ashes employed as cement substitution.…”

“…However, one aspect to highlight is the low or almost zero value of the loss on ignition (LOI), which accentuates the differences between the pozzolans of zeolitic [42] and bentonite origin [43]. This kind of composition, mostly silica, aluminium, iron, calcium, and magnesium, indicates the presence of typical volcanic ash minerals such as albite, hematite, magnetite, anorthite, augite, diopside, and quartz (the existence of an amorphous phase should also be considered) [19,41].…”

“…Cements with added pozzolanic materials of pyroclastic origin, in addition to their pozzolanic reactivity as demonstrated by Djeunou [17], also provide resistance to sulphates and seawater [18]-a very important characteristic considering the environment of the Canary Islands. Recently, Rosales et al [19] proved their effectiveness as a cementitious material with a fine fraction of volcanic ash from the Cumbre Vieja volcano (Spain). By using pozzolanic materials as active additions to cement, it is possible to reduce the emissions that are generated in the manufacture of cement, which accounts for about 8% [20][21][22] of total global CO 2 emissions.…”

Hydrothermal synthesis of zeolites using silica extracted from tropical volcanic ash

“…Although our sample showed trace amounts of Al 2 O 3 , other studies have reported higher alumina content in volcanic ashes. [16][17][18][19][20] The CaO was removed on purification, i.e., washing with 2.74 M HCl, resulting in purified volcanic ash (p-TVA) with 99 % SiO 2 , which was subsequently used as a high purity silica source for zeolite synthesis. The surface morphology of the raw and purified volcanic ash is illustrated in the SEM images in Figure 2.…”

“…This may be due to the fact that volcanic ash materials are heterogeneous in composition meaning that the nature of volcanic ash varies according to its source. [16][17][18][19][20][21] The conversion of volcanic ash to zeolites is therefore a challenge due to these variations. Nonetheless, volcanic ash is rich in aluminates and silicates, and its exploitation in the zeolite industry is worth exploring.…”