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Ca(OH) 2 or CaO · H 2 O: Calcium hydroxide (portlandite) C-S-H: 0.6–2.0 CaO · SiO 2 · 0.9–2.5 H 2 O, with variable composition within this range, and often also incorporating partial substitution of Al for Si: Calcium silicate hydrate: C-A-H: Phase more complex than C-S-H: Calcium aluminate hydrate C-A-S-H: This is even more complex than ...
Its solubility product K sp of 5.02 × 10 −6 at 25 °C, [1] its dissociation in water is large enough that its solutions are basic according to the following dissolution reaction: Ca(OH) 2 → Ca 2+ + 2 OH −. The solubility is affected by the common-ion effect. Its solubility drastically decreases upon addition of hydroxide or calcium sources.
In chemical terms, the pozzolanic reaction occurs between calcium hydroxide, also known as portlandite (Ca(OH) 2), and silicic acid (written as H 4 SiO 4, or Si(OH) 4, in the geochemical notation): Ca(OH) 2 + H 4 SiO 4 → CaH 2 SiO 4 ·2 H 2 O. or summarized in abbreviated cement chemist notation: CH + SH → C-S-H. The pozzolanic reaction can ...
Paper Coating 1) The paper or board 2) The first layer of coating to even out the surface 3) A second layer for an even smoother and whiter surface. Pigments that absorb in the yellow and red part of the visible spectrum can be added. As the dye absorbs light, the brightness of the paper will decrease, unlike the effect of an optical ...
Dicalcium phosphate is the calcium phosphate with the formula CaHPO 4 and its dihydrate. The "di" prefix in the common name arises because the formation of the HPO 4 2– anion involves the removal of two protons from phosphoric acid, H 3 PO 4.
It is a conjugate acid of phosphate [PO 4] 3-and a conjugate base of dihydrogen phosphate [H 2 PO 4] −. It is formed when a pyrophosphate anion [P 2 O 7] 4− reacts with water H 2 O by hydrolysis, which can give hydrogenphosphate: [P 2 O 7] 4− + H 2 O ⇌ 2 [HPO 4] 2−
Carbonatation is a slow process that occurs in concrete where lime (CaO, or Ca(OH) 2 ) in the cement reacts with carbon dioxide (CO 2) from the air and forms calcium carbonate. The water in the pores of Portland cement concrete is normally alkaline with a pH in the range of 12.5 to 13.5.
Ca 5 (PO 4) 3 OH + 5 H 2 SO 4 → 3 H 3 PO 4 + 5 CaSO 4 + H 2 O Ca 5 (PO 4) 3 F + 5 H 2 SO 4 → 3 H 3 PO 4 + 5 CaSO 4 + HF. Calcium sulfate (gypsum, CaSO 4) is a by-product, which is removed as phosphogypsum. The hydrogen fluoride (HF) gas is streamed into a wet (water) scrubber producing hydrofluoric acid. In both cases the phosphoric acid ...