Carbon hydroxide

Heavy metals often can be removed effectively by chemical precipitation in the form of carbonates, hydroxides, or sulfides. Sodium carbonate, sodium bisulfite, sodium hydroxide, and calcium oxide are all used as precipitation agents. The solids precipitate as a floe containing a large amount of water in the structure. The precipitated solids need to be separated by thickening or filtration and recycled if possible. If recycling is not possible, then the solids are usually disposed of to a landfill. 

Inorganic heavy metals are usually removed from aqueous waste streams by chemical precipitation in various forms (carbonates, hydroxides, sulfide) at different pH values. The solubiUty curves for various metal hydroxides, when they are present alone, are shown in Figure 7. The presence of other metals and complexing agents (ammonia, citric acid, EDTA, etc) strongly affects these solubiUty curves and requires careful evaluation to determine the residual concentration values after treatment (see Table 9) (38,39). 

Salts of Organic Acids. Calcium salts of organic acids may be prepared by reaction of the carbonate hydroxide and the organic acid (9). Calcium lactate [814-80-2] is an iatermediate ia the purification of lactic acid from fermentation of molasses. Calcium soaps, soaps of fatty acids, ate soluble ia hydrocarbons, and are useful as waterproofing agents and constituents of greases (9). 

Cupric chloride or copper(II) chloride [7447-39 ], CUCI2, is usually prepared by dehydration of the dihydrate at 120°C. The anhydrous product is a dehquescent, monoclinic yellow crystal that forms the blue-green orthohombic, bipyramidal dihydrate in moist air. Both products are available commercially. The dihydrate can be prepared by reaction of copper carbonate, hydroxide, or oxide and hydrochloric acid followed by crystallization. The commercial preparation uses a tower packed with copper. An aqueous solution of copper(II) chloride is circulated through the tower and chlorine gas is sparged into the bottom of the tower to effect oxidation of the copper metal. Hydrochloric acid or hydrogen chloride is used to prevent hydrolysis of the copper(II) (11,12). Copper(II) chloride is very soluble in water and soluble in methanol, ethanol, and acetone. 

Cu(N03 )26H2 0, is produced by crystallization from solutions below the transition poiat of 26.4°C. A basic copper nitrate [12158-75-7] Cu2(N02)(0H)2, rather than the anhydrous product is produced on dehydration of the hydrated salts. The most common commercial forms for copper nitrate ate the ttihydtate and solutions containing about 14% copper. Copper nitrate can be prepared by dissolution of the carbonate, hydroxide, or oxides ia nitric acid. Nitric acid vigorously attacks copper metal to give the nitrate and evolution of nitrogen oxides. 

Industrial Production and Uses of Sodium Carbonate, Hydroxide and Sulfate ... 

Naturally, the flux employed will depend upon the nature of the insoluble substance. Thus acidic materials are attacked by basic fluxes (carbonates, hydroxides, metaborates), whilst basic materials are attacked by acidic fluxes (pyroborates, pyrosulphates, and acid fluorides). In some instances an oxidising medium is useful, in which case sodium peroxide or sodium carbonate mixed with sodium peroxide or potassium nitrate may be used. The vessel in which fusion is effected must be carefully chosen platinum crucibles are employed for... 

Ba(ClC>4)2.3H20 is pptd when solns of Ba perchlorate are crystd, as in its prepn by the action of perchloric ac on Ba carbonate, hydroxide (Ref 2), or chloride (Ref 4) or by the action of a satd soln of AP on Ba hydroxide (Ref 5) Other Complexes. Complexes are known which contain 1 and 4 moles of ethylenediamine. The complex with 4 moles was found to decomp slowly over a broad temp range, but the one with 1 mole expld shortly after decompn started (Ref 12). A complex is formed with dioxane which is reported to be Ba(C104)2.2C4H802. 

Calcium/magnesium carbonate/hydroxide and calcium phosphate can be removed by using 5 to 15% hydrochloric acid at 140 to 150 °F, by recirculating tetrasodium EDTA at 200 to 300 °F, or by 7 to 10% sulfamic acid at 140 to 150 °F. The temperature may need to be a little higher to start the dissolution process. 

Carbonate/hydroxide Heavy metals Lime, calcium carbonate the metal... 

Ni carbonates, hydroxides, and sulfides are relatively insoluble Ni oxides in acidic solution may precipitate with neutralization. 

Magnesium carbonate hydroxide BCISC Quart. Safety Summ., 1965, 36(143), 44... 

See Formaldehyde Magnesium carbonate hydroxide See other inorganic bases, metal oxonon-metallates... 

One ore pretreatment process involves heating metal carbonates, hydroxides and some sulfides to metal oxides, which are more easily reduced to their elemental metal forms.. 

Except for those in Rule 1, carbonates, hydroxides, oxides, sulfides, and phosphates are insoluble. 

Copper ) bromide, molecular formula and uses, 7 1111 Copper cable, 17 848 Copper-cadmium alloys, 4 502 Copper(II) carbonate, molecular formula and uses of basic, 7 1111 Copper(II) carbonate hydroxide, 7 768-769 Copper(II) carboxylates, in VDC polymer stabilization, 25 720... 

Lithium carbonate, 0533 Lithium dithionite, 4687 Magnesium carbonate hydroxide, 0534 Magnesium nitrate, 4693 Magnesium nitrite, 4692 Magnesium sulfate, 4696 Potassium carbonate, 0531 Potassium nitrite, 4649 Silver hyponitrite, 0031 Sodium acetate, 0779 Sodium carbonate, 0552 Sodium disulfite, 4808 Sodium dithionite, 4807 Sodium hydrogen carbonate, 0390 Sodium hydrogen sulfate, 4446 Sodium metasilicate, 4805 Sodium nitrite, 4720 Sodium sulfate, 4806 Sodium tetraborate, 0185 Sodium thiosulfate, 4804... 

If solid samples are insoluble in water, some decomposition procedure must be used. For inorganic materials, decomposition with mineral acids is most often employed (for a survey of decomposition techniques see [33]). When the sample cannot be dissolved in an acid, it can either be fused (most often with alkali carbonates, hydroxides or their mixtures [157, 47]) or sintered (usually with mixtures of alkali carbonates with divalent metal oxides, sometimes in the presence of oxidants [54]). Sintering is usually preferable, because then contamination of the sample and the resultant ionic strength are lower than is the... 

Several of the inorganic bases have been involved in various laboratory or industrial scale incidents, individual entries being t Ammonia, 4497 Ammonium hydroxide, 4544 Barium hydroxide, 0208 Caesium amide, 4260 Calcium carbonate, 0317 Calcium hydroxide, 3928 Calcium oxide, 3937 Lead carbonate-lead hydroxide, 0726 Lithium carbonate, 0533 Magnesiiun carbonate hydroxide, 0534 Magnesiiun oxide, 4695 Potassiiun carbonate, 0531 Potassimn hydroxide, 4428 Sodimn carbonate, 0552 Sodium hydroxide, 4445 Sodimn oxide, 4802... 

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