جستجوی مقالات مرتبط با کلیدواژه « Clinker » در نشریات گروه « شیمی »

This study aims to determine the major elements of Portland cement type I and II (CEMI and CEMII) in a cement factory in north Tunisia and which metal elements are introduced into the production process. We determine also the metal input rate and their distribution at the entrance and exit of the process. The major elements were analyzed and the trace elements (Arsenic, barium, lead, mercury, boron, strontium, Cadmium, Chromium, copper, manganese, nickel, and zinc) were identified. The concentrations of heavy metals in CEMI showed no significant difference p

The present study conducted to investigate the potential use of PG in cement industry. This was accomplished by preparing mortar mixes contain Portland cement clinker (PPC) with thermally treated PG at different temperatures (200, 400, 600, 800 and 1000 °C) instead of raw gypsum (RG) at different proportions. The characteristics of prepared mortars were investigated after curing in water for different periods (3, 7, 28 and 90 days) by determination of setting time, compressive strength, bulk density, and total porosity. The hydration kinetics was evaluated by determination of free lime and chemically combined water contents. FTIR spectroscopic analysis was used to investigate the change in structure of some mortars after curing. The change in morphology and microstructure of hardened pastes was investigated using scanning electron microscopy (SEM). The results approved the possibility for the utilization of treated PG at 800 and 1000 °C instead of raw gypsum in cement industry.

For many years of production of phosphate fertilizer very large amounts of phosphogypsum (PG) occupied large area, causing chemical and radiological environmental. Using of PG in building materials represents a good method for lowering the cost of cement production and dispose of phosphogypsum as chemical and radioactive waste. Fresh wet hemihydrate phosphogypsum, cement and pozzolana additive were mechanically activated together and from mixing Portland pozzolanic cement (PPC) with PG, these mixes were prepared at different replacements (by weight) of raw gypsum (RG)with purified PG ranging from 1–5% . The purified PG was obtained by calcining PG at temperatures of 200, 400, 600, 800 and 1000 ᵒC. The compressive strength, bulk density, total porosity, combined water and free lime of different hardened mortars were obtained following 3, 7, 28 and 90 days of curing. In addition, the setting time of cement pastes. The highest percentage increase in strength was found to be for PG calcined at temperatures of 800 and 1000 ᵒC. The incorporation of PG in the cement paste has dramatically increased its initial and final setting times. FTIR spectroscopic analysis and scanning electron microscopy (SEM) were used for investigate the change in structure of mortars after curing and change in morphology and microstructure of some hardened pastes.