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The carbonates bind to plumbing surfaces providing seed crystals for further crystal growth, which build up as hard scale. [citation needed] Physical water treatment (PWT) devices cause microscopic mineral crystals to form and remain suspended as they flow with the water, while also acting as seeds for further crystal growth. As water is heated ...
Magnesium carbonate is ordinarily obtained by mining the mineral magnesite. Seventy percent of the world's supply is mined and prepared in China. [9] Magnesium carbonate can be prepared in laboratory by reaction between any soluble magnesium salt and sodium bicarbonate: MgCl 2 (aq) + 2 NaHCO 3 (aq) → MgCO 3 (s) + 2 NaCl(aq) + H 2 O(l) + CO 2 (g)
Like magnesium oxide, it will generate a basic carbonate when placed in the air. [3] Magnesium sulfide can be produced by the reaction of magnesium and hydrogen sulfide, or by the reaction of magnesium sulfate and carbon disulfide at high temperature: [6] Mg + H 2 S → MgS + H 2 3 MgSO 4 + 4 CS 2 → 3 MgS + 4 COS + 4 SO 2
Magnesite can also be formed via the carbonation of magnesium serpentine (lizardite) via the following reaction: 2 Mg 3 Si 2 O 5 (OH) 4 + 3 CO 2 → Mg 3 Si 4 O 10 (OH) 2 + 3 MgCO 3 + 3 H 2 O. However, when performing this reaction in the laboratory, the trihydrated form of magnesium carbonate (nesquehonite) will form at room temperature. [6]
Biogenic calcium carbonate is formed when marine organisms, such as coccolithophores, corals, pteropods, and other mollusks transform calcium ions and bicarbonate into shells and exoskeletons of calcite or aragonite, both forms of calcium carbonate. [57] This is the dominant sink for dissolved calcium in the ocean. [114]
The reaction of magnesium carbonate with the free alkali hydroxides present in the cement porewater also leads to the formation of expansive brucite. MgCO 3 + 2 NaOH → Mg(OH) 2 + Na 2 CO 3. This reaction, one of the two main alkali–aggregate reaction (AAR) is also known as alkali–carbonate reaction.
The most widely used anticaking agents include the stearates of calcium and magnesium, silica and various silicates, talc, as well as flour and starch. Ferrocyanides are used for table salt. [ 1 ] The following anticaking agents are listed in order by their number in the Codex Alimentarius by the Food and Agriculture Organization of the UN.
The first report of the hydrothermal growth of crystals [4] was by German geologist Karl Emil von Schafhäutl (1803–1890) in 1845: he grew microscopic quartz crystals in a pressure cooker. [5] In 1848, Robert Bunsen reported growing crystals of barium and strontium carbonate at 200 °C and at pressures of 15 atmospheres, using sealed glass ...