1,721,056 research outputs found
Release of pollutants from hydrated mixtures of cement and fly ash with a high sulphate and chloride content
No full textMixtures of cement and fly ash from Municipal Solid Waste (MSW), with a high content of sulphate and chloride as well as a large concentration of heavy metals, were appropriately hydrated. In the leaching test using deionised water, these mixtures showed an efficient interaction of the sulphate with the cementitious matrix. The behaviour of chloride release from pastes hardened has shown that an acceleration of the hydration process takes place. This acceleration was particularly intense for the mixtures with an intermediate fly ash content. The release of polluting elements as Cu, Zn, Cd, Pb, Cr(VI) from the solidified mixtures was correlated to the degree of stabilisation of the fly ash
Malte Idrauliche per il Restauro di Strutture Murarie di Opere di Interesse Storico-Architettonico
No full textFly Ash with High Sulphate and Chloride Content: Solidification and Stabilisation Using Hydraulic lime
No full textThis paper examines the solidification/stabilisation treatment of two fly ash samples from a Municipal Solid Waste (MSW) incineration plant using a lime-pozzolan binder. The two examined fly ash samples were characterised by a high chloride and sulphate content and by a significant concentration of heavy metals. The effective development of hydrate phases during hydration of hydraulic lime-fly ash mixtures allows us to stabilise numerous pollutants in hardened pastes. The release of pollutants into the leachants is limited and decreases with the curing period of the pastes
Release of pollutants from hardened pastes containing fly ash
No full textAn investigation was made of the release in demineralized water bf heavy metals, chloride and sulphate ions from cementitious pastes containing fly ash coming from Municipal Solid Wastes. The analytical procedure applied with a periodical changing of the leachant (dynamic test) on the solidified mixtures, characterized by different curing periods, has allowed to evidence a cumulative percent increase of;release even more lower with leaching time. A remarkable decrease of the eluate concentration as regards long cured pastes was found. The characteristic leaching behaviour of chloride, sodium and potassium elements has given useful informations on overall progress of solidification/stabilization processes of cement-fly ash mixtures
Behaviour towards leaching of fly ash from a municipal solid waste incineration plant
No full textAn examination was made of the behaviour towards leaching of fly ash produced by a municipal solid waste incineration plant. The release of heavy metals and chloride and sulphate ions was evaluated by means of leaching solutions of different pH values. The chemical composition and mineralogical characteristics of fly ash leached with water was compared with those of the same fly ash untreated. It was found that the water-fly ash interaction causes a marked reduction in the more soluble salts and the formation of some hydrate products in the fly ash. The leaching test at pH 5.0 with 0.5 M acetic acid applied to fly ash solidified with pozzolanic cement revealed a good degree of stabilization achieved
Malte idrauliche per il restauro di strutture murarie di opere di interesse storico-architettonico
No full text"Solidificazione e Stabilizzazione di Fly Ash ad Elevato Contenuto di Solfato e Cloruro con Calce Idraulica"
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"Risultati di uno Studio del Rilascio in Soluzione Acquosa di Inquinanti da Fly Ash Solidificate e Stabilizzate"
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