Cement anhydrite

Barite occurs in trace amounts as patchy poikilo-topic, grain-replacive cement associated with partially dissolved carbonate cement. Anhydrite cement forms < 1 vol% in the fine- to medium-grained sandstones that contain micritic carbonate intraclasts (calcretes/dolocretes), occurring in the upper part of... 

Fig. 11. Paragenetic sequence for the Upper Angel Formation, Angel Field. Dolomite cementation was a relatively late, pore-filling diagenetic event that occurred, at least in part, synchronously with microfracturing and hydrocarbon migration (see Fig. IOC). Later-stage anhydrite cement precipitated in some Angel Formation sandstones at Angel-2 and, to a lesser extent, at Angel-4.

Anhydrite Cement K-feldspar Cement Dolomite Cement Albite Cement Quartz Cement Calcite Cement Pyrite... 

Several lines of evidence suggest the involvement of TSR. Partially dissolved remnants of early diagenetic anhydrite cement are found embedded in quartz cement (Fig. 12). Fluid inclusion data indicate that nodular quartz cement with anhydrite inclusions (Fig. 15) formed at elevated temperatures, suggesting that anhydrite dissolution may have coincided with high temperature TSR. Post-pyrobitumen carbonate and pyrite cements and nodules are also present in the Norphlet and may represent late diagenetic precipitates associated with TSR. Pyrite cement from the Norphlet has sulphur isotope ratios that are identical to those of the Pine Hill Anhydrite (Table 3) and within the range reported for Jurassic seawater (Hoefs... 

Parallel with cement production development the significant progress in cement chemistry was achieved. The real revolution we owe to French scientist Le Chat-eher. This great chemist determined the phase composition of Portland cement clinker and the hypothesis of hydration process. Le Chatelier stated that, similarly as in the case of gypsum, the anhydrite cement components dissolve, the solution became oversaturated in relation to hydrates, which causes their crystallization [3],... 

Jing, Wu Kang, GABD Hike s fortune, fan, have constitutional high translation research and application of gypsum, China industry press, 1963, p7-150 A.Jarrosinski. Properties of Anhydrite Cement Obtained from Apatite Phosphogypsum. CCR. VOL, 24, 1994,p99-108... 

The gases from the kiln contain about 9% sulphur dioxide. (The calcium oxide combines with the silica to form a silicate slag which, when cool, is crushed and mixed with some anhydrite to give cement, a valuable by-product.)... 

Not all rocks shatter well by impact. Impacl breaking is best suited for the reduction of relatively nonabrasive and low-silica-content materials such as hmestone, dolomite, anhydrite, shale, and cement rock, the most popular application being on limestone. 

Carbonates and Sulfates Carbonates include limestone, cal-cite, marble, marls, chalk, dolomite, and magnesite the most important sulfates are barite, celestite, anhydrite, and gypsum these are used as fillers in paint, paper, and rubber. (Gypsum and anhydrite are discussed below as part of the cement, lime, and gypsum industries.)... 

Since we have no direct information about the chemistry of the Fountain fluid, we assume that its composition reflects reaction with minerals in the evaporite strata that lie beneath the Lyons. We take this fluid to be a three molal NaCl solution that has equilibrated with dolomite, anhydrite, magnesite (MgCC>3), and quartz. The choice of NaCl concentration reflects the upper correlation limit of the B-dot (modified Debye-Hiickel) equations (see Chapter 8). To set pH, we assume a CO2 fugacity of 50, which we will show leads to a reasonable interpretation of the isotopic composition of the dolomite cement. 

Oil in the Cretaceous Dakota sandstone, a shallower aquifer than the Lyons, has migrated laterally as far as 150 km into present-day reservoirs (Clayton and Swetland, 1980). In contrast, oil has yet to be found in the Lyons outside the deep strata where it was generated. The formation of anhydrite and dolomite cements may have served to seal the oil into reservoirs, preventing it from migrating farther. 

Cementation by calcite, dolomite, anhydrite, pyrobitumen and silica... 

Other types of cements include anhydrite, barite, pyrite, iron hydroxides haematite, albite and apatite and are subordinate. 

Uses. The insoluble anhydrite is used in cement formulations and as a paper filler the soluble anhydrite is used as a drying agent the hemihydrate is used for wall plaster and wall-board gypsum is used in manufacture of plaster of paris and portland cement. 

The soluble sulfate versus time curve for the cement containing the natural anhydrite is radically changed when CLS is present [130, 131]. The rate of solution of natural anhydrite, which is much slower than that of gypsum or calcium sulfate hemihydrate, is further retarded in the presence of chemical admixtures, which leads to a sulfate-starved system in the concrete, often producing rapid set and an increase in rate of concrete slump loss (Fig. 7.42). Apparently the adsorption of the lignosulfonate by the natural anhydride plus the rapid reaction between the soluble SO3 and the... 

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