摘要:
A high early strength pozzolan cement includes larger sized pozzolan particles and smaller sized hydraulic cement particles which contain tricalcium silicate (e.g., Portland cement). Particles larger than 10 μm are predominantly (50%, 65%, 75%, 85% or 95%) pozzolan particles, and particles smaller than 10 μm are predominantly (50%, 65%, 75%, 85% or 95%) hydraulic cement particles. Excess calcium from the hydraulic cement forms calcium hydroxide available for reaction with the pozzolan particles, optionally in combination with supplemental lime. At least 30%, 40%, 45%, 55%, 65% or 75% of the pozzolan cement (combined pozzolan and hydraulic cement particles) consists of pozzolan, and less than 70%, 60%, 55%, 45%, 35% or 25% consists of hydraulic cement.
摘要:
The invention concerns a method for beneficiation of fly ash particles comprising: determining the heat value of the fly ash particles; comparing the determined heat value of the fly ash particles with a minimum heat value K; feeding an inlet of a combustor (5) with a feed material comprising the fly ash particles and, in case the determined heat value is lower than the minimum heat value K, fuel in sufficient quantity to assure that the heat value of the raw material is greater than or equal to the minimum heat value K; supplying an upstream airflow to the combustor (5) so as to carry the feed material in suspension from the inlet to an outlet of the combustor; operating the combustor (5) at a temperature of at least 700° C.; collecting beneficiated fly ash particles from the airflow at the outlet of the combustor (5). The invention also concerns an installation for implementation of the said method.
摘要:
Lightweight well cement compositions, comprised of a hydraulic cement, water and an additive comprising a suspension of microspheres in water gelled with sodium bentonite, are used in the annulus between a pipe and the well bore for sealing the pipe in zones or formations which readily fracture at low hydrostatic pressure.
摘要:
Geopolymeric cements based on aluminosilicate fly ash of class F, which, contrary to the prior art, are harmless to use and harden at ambient temperature, favouring their use in common applications in the construction and civil engineering fields. This harmlessness is achieved thanks to a mixture containing: 10 to 15 parts by weight of a non-corrosive alkali metal silicate solution in which the M2O:SiO2 molar ratio is less than 0.78, preferably less than 0.69, and the SiO2:M2O ratio is greater than 1.28, preferably greater than 1.45, M denoting Na or K; added to this are 10 to 20 parts by weight of water and 5 to 15 parts by weight of blast-furnace slag having a specific surface area of less than 400 m2/kg, preferably less than 380 m2/kg and also 50 to 100 parts by weight of class F aluminosilicate fly ash.
摘要:
This invention relates to a mixture comprising the following proportion of masses: from 0.4 to 4 %, preferably 0.8 to 1.7 %, content of ultrafine grain size materials constituted by D90 particles measuring less than 1 μm and/or a BET specific surface area greater than 6 m2/g; from 1 to 6 %, preferably 2 to 5 %, of Portland cement; from 8 to 25 %, preferably 12 to 21 %, of fine grain size materials constituted by particles whose DlO and D90 are between 1 μm and 100 μm and have a BET specific surface less than 5 m2/g, both different from the cement; from 25 to 50 %, preferably 30 to 42 %, of medium grain size materials constituted by particles whose Dl 0 and D90 are between 100 μm and 5 mm and from 25 to 55 %, preferably 35 to 47 %, of superior grain size material constituted by particles whose Dl 0 which is greater than 5 mm. The invention also concerns, in particular, premixed concrete compositions and combined hardened concrete, as well as their preparation processes.
摘要:
The object is to remove unburned carbon in a fly ash in a stable and economically advantageous manner. A fly ash, water and a trapping agent are mixed together in a hybrid mixer (2), a shearing force is applied to the mixture to prepare a slurry containing surface-modified unburned carbon within a short time, a foaming agent is added to the slurry, and then the unburned carbon is separated by performing flotation separation in a flotator (11).
摘要:
The present invention relates to settable compositions for general purpose concrete construction containing Class-F fly ash, Class-C fly ash or slag, and cement kiln dust (CKD) as a substantial replacement for Portland cement conventionally used in such compositions. The compositions of the present invention provide high early strength thereby allowing the concrete structure to be put into service sooner, reducing labor cost, and allowing precast concrete and concrete masonry manufacturers to achieve rapid form and mold turnover.