Person:
Monte Lara, María Concepción

First Name

María Concepción

Last Name

Monte Lara

URI

https://hdl.handle.net/20.500.14352/76231

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Químicas

Department

Ingeniería Química y de Materiales

Area

Ingeniería Química

Identifiers

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Search Results

Now showing 1 - 10 of 23

Extending the limits of paper recycling - improvements along the paper value chain
(Forest Systems, 2013) Blanco Suárez, María Ángeles; Miranda Carreño, Rubén; Monte Lara, María Concepción
Aim of study: The purpose of this study is to analyze how paper recycling activities in Europe can be extended through different improvements along the paper value chain. The importance of this study lies in the identification of the present barriers in paper recycling and how they can be overcome. Area of study: Europe. Material and methods: All the main stages along the paper value chain have been analyzed for possible improvements: collection of recovered paper (availability and quality), sorting of recovered paper, paper production, and printing and converting activities. Main results: To increase paper recycling in Europe the following improvements are necessary. First, it is mandatory to increase the availability of recovered paper through more efficient collection systems (avoiding the use of commingled collection systems) and limiting the competition with energy purposes and the exports. Second, it is necessary to extend sorting activities, which can be achieved by reducing sorting costs by the use of automatized sorting systems. Third, there is a need to increase the recyclability of paper products by the commitment of printing and converting industries to use recycling-friendly printing inks and adhesives. Finally, environmental awareness of the citizens is still an important driver for increasing recycling activities, affecting not only recovery but to all the stages along the paper recycling chain. Research highlights: Although the recycling rate in Europe is already very high (68.9%), there is still room to further extend paper recycling activities through different improvements along the paper value chain.
Comparison of ultrafiltration and dissolved air flotation efficiencies in industrial units during the papermaking process
(APPITA Journal, 2011) Monte Lara, María Concepción; Ordóñez Sanz, Ruth; Hermosilla Redondo, María Daphne; González Sánchez, Mónica; Blanco Suárez, María Ángeles
The efficiency of an ultrafiltration unit has been studied and compared with a dissolved air flotation system to get water with a suited quality to be reused in the process. The study was done at a paper mill producing light weight coated paper and newsprint paper from 100% recovered paper. Efficiency was analysed by removal of turbidity, cationic demand, total and dissolved chemical oxygen demand, hardness, sulphates and microstickies. Moreover, the performance of the ultrafiltration unit and the membranes were studied deeply, analysing its variability during the filtration process. As expected, the ultrafiltration gave higher removal efficiencies than the dissolved air flotation cell in parameters like turbidity, cationic demand, dissolved chemical oxygen demand and microstickies. The greatest difference in performance between the units concerned cationic demand and dissolved chemical oxygen demand. Ultrafiltration was influenced by the operating time, decreasing the removal efficiency of the dissolved fraction by 75% and of the colloidal fraction by 30% after 312 of running. Membrane autopsy, carried out to identify the cause of poor membrane performance, showed that the active layer was degraded due to the effect of suspended solids.
Time Variations of Macrostickies and Extractable Stickies Concentrations in Deinking
(Industrial & Engineering Chemistry Research, 2010) MacNeil, Donald; Miranda Carreño, Rubén; Monte Lara, María Concepción; Blanco Suárez, María Ángeles; Sundberg, Anna
The stickies content, both macrostickies and stickies extractable in a solvent, was determined for samples taken at short time intervals from deinking lines, producing deinked pulp for newsprint production. The study was carried out at three mills on different continents, with each having a different source of recycled paper as raw material. The short-term variations in extractable stickies in the incoming raw material were quite extreme, with differences of 100% being seen within hours. Despite this, the final deinked pulp contained fewer sudden variations and had no correlation to the incoming stickies content. While the raw material appeared to affect the incoming stickies content, a well-optimized deinking line was able to buffer the raw material variability, and the final stickies content was more dependent on the deinking process. This result was seen for the two mills examined for this phenomenon, despite a different raw material supply. Macrostickies were found to exhibit the same tendencies, although with smaller and less sudden variations. However, the variations of macrostickies and extractable stickies never correlated, even when both were measured for the same pulp fraction, thus confirming that solvent extraction is not an appropriate method for the determination of macrostickies and is more a reflection of microstickies.
Improving deposition tester to study adherent deposits in papermaking
(Chemical Engineering Research and Design, 2012) Monte Lara, María Concepción; Sánchez, Mónica; Blanco Suárez, María Ángeles; Negro Álvarez, Carlos Manuel; Tijero Miquel, Julio Félix
Conventional methods used for the quantification of adherent material contained in a pulp suspension propose either filtration of the sample, which may lead to loss of sticky material in the filtrate, or dilution of the pulp, which may cause destabilization of the dissolved and colloidal material; thus, leading to unreliable results. In 1998, the Cellulose and Paper Group of University Complutense of Madrid developed a deposition tester which aimed to quantify the adherence of material (microstickies and secondary stickies from dissolved and colloidal material) that was present in white waters generated during papermaking processes. In this paper, an improved deposition tester capable of directly studying the deposition tendency of total stickies in pulps without dilution is described and validated. The design of this device prevents the rotor system from being clogged and blocked by pulps, hence, being able to quantify deposits without having to apply any filtration and/or dilution stages. In addition, the study provides determination of the equipment optimum operating conditions as well as comparison between the improved deposition tester and the one previously developed. Results show that this deposition tester can determine the adherent material contained in pulps with a consistency up to 1%. The comparison of results obtained after applying both deposition quantification methods shows that the quantities of deposits that were measured with the improved tester are slightly lower than those obtained with the application of the conventional method; however, they are in the same order of magnitude. Therefore, it is possible for the improved tester to determine total stickies in all cases, including cases that it is not convenient to apply a filtration and/or a dilution stage.
Impact of increased collection rates and the use of commingled collection systems on the quality of recovered paper. Part 1: Increased collection rates
(Waste Management, 2011) Miranda Carreño, Rubén; Monte Lara, María Concepción; Blanco Suárez, María Ángeles
The recovery and utilization of recovered paper have increased over past decades all over the world due to economic, environmental, and social issues. However, it is well known that an extended recovered paper collection is detrimental to its quality, either by the exploitation of lower quality sources such as households, or the spreading of commingled systems instead of selective collection systems. The influence of these two factors was assessed by analyzing the quality of different recovered paper grades used as raw material in a mill located in Madrid (Spain) producing newsprint and light weight coated paper from recovered paper. Part 1 of the paper deals with the impact of increased collection rates on the quality of recovered paper and Part 2 with the use of commingled collection systems. Results of Part 1 show that increased collection rates have a large impact on the quality of the recovered paper. The quality, measured as total unusable material and moisture contents, had deteriorated very rapidly in only four years (2005-2008) as a consequence of increased collection rates. Collection rates increased in Spain from 58.5% to 68.6% during this period, resulting in more than 50% increase of total unusable material and 25% of moisture content. The downgrading of the quality of recovered paper is one of the major threats for extending the current limits of paper recycling. Therefore, future challenge is to increase its availability but maintaining its quality.
Waste management from pulp and paper production in the European Union
(Waste Management, 2009) Monte Lara, María Concepción; Fuente González, Elena De La; Blanco Suárez, María Ángeles; Negro Álvarez, Carlos Manuel
Eleven million tonnes of waste are produced yearly by the European pulp and paper industry, of which 70% originates from the production of deinked recycled paper. Wastes are very diverse in composition and consist of rejects, different types of sludges and ashes in mills having on-site incineration treatment. The production of pulp and paper from virgin pulp generates less waste but the waste has similar properties to waste from the production of deinked pulp, although with less inorganics. Due to legislation and increased taxes, landfills are quickly being eliminated as a final destination for wastes in Europe, and incineration with energy recovery is becoming the main waste recovery method. Other options such as pyrolysis, gasification, land spreading, composting and reuse as building material are being applied, although research is still needed for optimization of the processes. Due to the large volumes of waste generated, the high moisture content of the waste and the changing waste composition as a result of process conditions, recovery methods are usually expensive and their environmental impact is still uncertain. For this reason, it is necessary to continue research on different applications of wastes, while taking into account the environmental and economic factors of these waste treatments.
Recycled Fibers for Sustainable Hybrid Fiber Cement Based Material: A Review
(Materials, 2021) Balea Martín, Ana; Fuente González, Elena De La; Monte Lara, María Concepción; Blanco Suárez, María Ángeles; Negro Álvarez, Carlos Manuel
Reinforcing fibers have been widely used to improve physical and mechanical properties of cement-based materials. Most fiber reinforced composites (FRC) involve the use of a single type of fiber to improve cement properties, such as strength or ductility. To additionally improve other parameters, hybridization is required. Another key challenge, in the construction industry, is the implementation of green and sustainable strategies based on reducing raw materials consumption, designing novel structures with enhanced properties and low weight, and developing low environmental impact processes. Different recycled fibers have been used as raw materials to promote circular economy processes and new business opportunities in the cement-based sector. The valuable use of recycled fibers in hybrid FRC has already been proven and they improve both product quality and sustainability, but the generated knowledge is fragmented. This is the first review analyzing the use of recycled fibers in hybrid FRC and the hybridization effect on mechanical properties and workability of FRC. The paper compiles the best results and the optimal combinations of recycled fibers for hybrid FRC to identify key insights and gaps that may define future research to open new application fields for recycled hybrid FRC.
Polymeric Branched Flocculant Effect on the Flocculation Process of Pulp Suspensions in the Papermaking Industry
(Industrial & Engineering Chemistry Research, 2009) Blanco Suárez, María Ángeles; Fuente González, Elena De La; Monte Lara, María Concepción; Cortés, Noelia; Negro Álvarez, Carlos Manuel
This paper presents the effect of the structure of cationic polyacrylamides (CPAMs) on flocculation of pulpsuspensions and floc properties. A focused beam reflectance measurement (FBRM) probe was used to monitor flocculation, deflocculation, and reflocculation processes in real time. To carry out the study, 1% elemental chlorine free (ECF) eucalyptus kraft pulp containing 20% ground calcium carbonate (GCC) was used. Results show that the effect of the CPAM structure depends on charge density and polymer dose. Floc size does not always decrease with branching degree, whereas floc stability and reflocculation ability increased when highly charged and branched CPAM was used. These findings indicate that the use of highly branched CPAMs with very high molecular weight is very promising as a retention aid method to improve the papermaking process.
Pitch detackification with natural and modified talcs
(Tappi Journal, 2011) Tijero Cruz, Antonio; Monte Lara, María Concepción; Blanco Suárez, María Ángeles
Pitch deposition in the pulp or in different parts of the manufacturing system can lead to a decrease in the quality of the final paper produced and to manufacturing efficiency problems. Tackiness is the property of pitch which related to the deposit formation. One of the methods to control pitch deposition in the pulp and paper industry is the use of the talc. The talc acts primarily by a detackification mechanism and hence must be part of the deposit to control further deposition. The effectiveness of talc as control agent depends on its structural and surface characteristics, e.g. specific surface, surface energy, surface charge and ratio lypophilic/hydrophilic surface, being these related to its mineral composition and the thermal and surface treatments it has undergone. Five commercial talcs, corresponding to two groups of different mineralogical compositions, have been tested to determine their detackification capacity using the deposition tester developed by the Complutense University of Madrid. In this method, the quantification of the deposits is carried out by an image analysis (IA) of stainless steel collectors on which the deposit has formed. After IA a qualitative analysis to determine the deposit organic fraction is carried out by gas chromatography (CG) after deposit extraction. The detackification capacity is expressed as the reduction of the deposits formed on the collectors when the different talcs at several concentrations are added to the pulp suspensions. The results show that pitch detackiness by talc addition is related to talc concentration and surface properties of mineral, as for example chlorite proportion, surface area and surface treatment and to the adsorption capacity of pitch on talcs. The general conclusions are that the talc having the highest quantity of mineral talc presents the best detackification capability and that all talcs studied have an appreciable detackification reduction at low proportion of addition.
Pitch adsorption on natural and modified talcs
(Journal of Pulp and Paper Science, 2009) Tijero Cruz, Antonio; Monte Lara, María Concepción; Blanco Suárez, María Ángeles; Negro Álvarez, Carlos Manuel; Tijero Miquel, Julio Félix
Talc is used traditionally for pitch control in papermaking. The effectiveness of talcs as control agent of dissolved and colloidal pitch depends on its structural and surface characteristics of minerals. Talcs are modified by thermal and surface treatments to obtain different properties e.g specific surface, surface energy, surface charge and ratio lypophilic/hydrophilic surface. Five commercial talcs have been tested to determine its capacity to adsorb the lypophilic contaminants by experiments of adsorption isotherms. The talcs correspond to two groups of different mineralogical compositions: one with high concentration of talc and some dolomite; and the other, with medium concentrations of talc and chlorite. Colloidal dispersions of extractives were obtained by extraction of Eucalyptus globulus wood at pilot plant scale with acetone, evaporation of the solvent and reextraction with hexane to increase the selectivity of lypophillic compound extraction. The isotherms of adsorption of the pitch dispersions were carried out at 50ºC on the different talcs. The adsorption took place by a mechanism of colloidal adsorption and the results obtained were adjusted to the Langmuir equation. Results show that talc addition to bleaching waters or process waters can produce high reductions of colloidal pitch concentrations, at comparatively low doses.