Hydrates magnesium carbonate

Transparent white pigments (extenders) commonly used in inks, in order of decreasing transparency, ate alumina hydrate, magnesium carbonate, calcium carbonate, blanc fixe (precipitated barium sulfate), talc, and clay. Extenders ate sometimes used to reduce the color strength and change the theology of inks. 

The double salt is decomposed by hot water and magnesia, forming potassium carbonate and insoluble hydrated magnesium carbonate ... 

Depending upon the manufacturing process used, the composition of the magnesium carbonate obtained may vary from normal hydrated magnesium carbonate to basic hydrated magnesium carbonate. 

The precipitation of hydrated magnesium carbonate, such as hydromagnesite, from the filtered leachate, can be achieved using air sparging and/or heating to remove excess carbon dioxide. Since magnesium bicarbonate is not stable in the absence of dissolved carbon dioxide, the following precipitation occurs at temperatures above 55°C see reaction (9.13) ... 

Hypothetical reaction pathways chosen to model the L2 leachate-Uinta Sandstone system are illustrated in Figure 5. As a first approximation, dissolution/precipitation reactions affecting the mass balance of Na, K, Mo, SO4, and Cl were not considered. Instead, based upon the solubility controls discussed in the previous sections of this paper, the working hypothesis for the simulations is that the recarbonation of L2 leachate drives the reactions toward equilibrium. Along the path toward equilibrium, recarbonation is accompanied by the precipitation and dissolution of sepiolite, calcite, and an inferred hydrated magnesium carbonate mineral such as hydromagnesite. 

Formula weight (NaaNgOg 9H3O) 268.14. Small granular crystals or plates. Loses water of crystallization under vacuum. In its anhydrous form, it resembles hydrated magnesium carbonate. Readily soluble in HgO. 

Classification Crystalline salt Definition Basic dehydrated magnesium carbonate or normal hydrated magnesium carbonate the naturally occurring mineral is magnesite Empirical CO3 Mg... 

Mir-slaked lime contains various proportions of the oxides, hydroxides, and carbonates of calcium and magnesium which result from excessive exposure of quicklime to air that vitiates its quaUty. It is partially or largely decomposed quicklime that has become hydrated and carbonated. 

Properties. The physical properties of the normal magnesium carbonates are given in Table 3, those of the basic magnesium carbonates in Table 4. Magnesium carbonate is insoluble in C02-free water. The solubiUty products, iC, for magnesium carbonate and some hydrates foUow (38). 

Normal, hydrated, and the basic magnesium carbonates react with acids to yield salts which can be recovered by crystallization (43). Magnesium carbonate forms many double salts, some of which are Hsted ia Table 5. 

Cellulose acetate Silica gel Scoured wool Sawdust Rayon waste Fluorspar Tapioca Breakfast food Asbestos fiber Cotton linters Rayon staple Starch Aluminum hydrate Kaolin Cryolite Lead arsenate Cornstarch Cellulose acetate Dye intermediates Calcium carbonate White lead Lithopone Titanium dioxide Magnesium carbonate Aluminum stearate Zinc stearate Lithopone Zinc yellow Calcium carbonate Magnesium carbonate Soap flakes Soda ash Cornstarch Synthetic rubber... 

Recently, the influence of the preparation method of various MgO samples on their catalytic activity in the MPV reaction of cyclohexanone with 2-propanol has been reported 202). The oxides were prepared by various synthetic procedures including calcination of commercially available magnesium hydroxide and magnesium carbonate calcination of magnesium hydroxides obtained from magnesium nitrate and magnesium sulfate sol-gel synthesis and precipitation by decomposition of urea. It was concluded that the efficiency of the catalytic hydrogen transfer process was directly related to the number of basic sites in the solid. Thus, the MgO (MgO-2 sample in Table IV) prepared by hydration and subsequent calcination of a MgO sample that had been obtained from commercially available Mg(OH)2 was the most basic and the most active for the MPV process, and the MgO samples with similar populations of basic sites exhibited similar activities (Table IV). 

Formula MgCOs MW 84.31 several hydrated and basic carbonates are also known that are stable and occur in nature. The types, names, formulas and CAS Registry numbers of anhydrous, hydrated and basic magnesium carbonates are tabulated below ... 

The solution is filtered to remove impurities and the filtrate is subjected to vacuum or aeration to yield insoluble magnesium carbonate as a hydrated salt ... 

The trihydrate, MgC03 3H20 or other hydrates on heating form basic magnesium carbonates, the product compositions depending on degree of water of crystallization and temperature. 

Hydrated magnesium sulfate occurs in nature as the minerals kieserite and epsomite. The salt is mined in large scale from these and other naturally occurring minerals. The salt also is prepared in the laboratory by the action of sulfuric acid on magnesium oxide, hydroxide, or carbonate followed by evaporation and crystallization ... 

Fuller s earth (hydrated aluminosilicate) Magnesium oxide Charcoal Alumina Magnesium trisilicate Silica gel Calcium hydroxide Magnesium carbonate Calcium phosphate Calcium carbonate Sodium carbonate Talc Inulin Sucrose = starch Petroleum ether, b 40-60°- Petroleum ether, b 60-80°. Carbon tetrachloride. Cyclohexane. Benzene. Ethyl ether. Chloroform. Ethyl acetate. Acetone. Ethanol. Methanol. Pyridine. Acetic acid. 

And finally, appendices provide a user s guide for the FREZCHEM model and tables of model parameters. Version 9.2 of this model includes the precipitation-dissolution of chloride, nitrate, sulfate, and bicarbonate-carbonate salts of calcium, magnesium, sodium, potassium, and ferrous iron. This version also contains strong acid chemistries (hydrochloric, nitric, and sulfuric), gas hydrate chemistries (carbon dioxide and methane), and tem-perature/pressure dependencies. Electronic copies of the FORTRAN code are available from the senior author (giles.marion dri.edu). 

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