Water-soluble sulfates, chlorides and nitrates

Part 13 of ISO 787 determines water-soluble sulfates, chlorides and nitrates. The sample extract can be prepared by either cold or hot extraction method described in Section 4.28. The sulfates in the extract are determined by precipitation with barium chloride, the chlorides are determined by titration with silver nitrate, and the nitrates are determined by a colorimetric method using Nessler reagent. Part 19 gives an alternative method of determination of nitrates by a salicylic acid method. 

1 ASTM D 3349-93. Absorption coefficient of ethylene polymer materials pigmented with carbon black. 

5 ASTM D 985-93. Brightness of pulp, paper, and paper board (directional reflectance at 457 nm). 

6 ASTM D 185-95. Coarse particles in pigments, pastes, and paints. 

7 ASTM E 308-96. Computing the colors of objects by using CIE system. 

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Water-Soluble Sulfates, Chlorides, and Nitrates. The procedures are applicable to pigments and extenders. The choice of hot or cold extraction depends on the properties of the pigment and should be agreed. The anions are determined by the usual analytical methods. For standards, see Table 1 ( Sulfates , Chlorides , and Nitrates ). Apparatus Nessler tubes or spectrophotometer, equipment for pH measurement. 

The solubility of organomercury compounds depends primarily on the nature of the X group nitrates and sulfates tend to be salt-like and relatively water-soluble, whereas chlorides are covalent, nonpolar compounds of low water solubility. Methyl mercury compounds tend to be more volatile than other organomercury compounds. 

In aqueous solution, erbium is always trivalent, Er3+. It forms water-insoluble trivalent salts, such as fluoride, ErFs, carbonate, Er2(COs)2, hydroxide, Er(OH)3, phosphate, ErP04, and oxalate Er2(C204)s. It also forms water-soluble salts, chloride, ErCls bromide, ErBrs iodide, Erls sulfate, Er2(S04)s and nitrate, Er(NOs)3. Evaporation of solutions generally yields hydrated salts. 

The chlorides, bromides, nitrates, bromates, and perchlorate salts ate soluble in water and, when the aqueous solutions evaporate, precipitate as hydrated crystalline salts. The acetates, iodates, and iodides ate somewhat less soluble. The sulfates ate sparingly soluble and ate unique in that they have a negative solubitity trend with increasing temperature. The oxides, sulfides, fluorides, carbonates, oxalates, and phosphates ate insoluble in water. The oxalate, which is important in the recovery of lanthanides from solutions, can be calcined directly to the oxide. This procedure is used both in analytical and industrial apptications. 

Quality of Product. Ammonium nitrate, commonly made from pure synthetic raw materials, is itself of high purity. If the product is intended for use in explosives, it should be at least 99% ammonium nitrate and contain no more than 0.15% water. It should contain only small amounts of water-insoluble and ether-soluble material, sulfates and chlorides, and should not contain nitrites. The soHd product ought to be free from alkalinity, but be only slightly acidic. 

In metallic form, barium is very reactive, reacting readily with water to release hydrogen. In aqueous solution it is present as an ion with a +2 charge. Barium acetate, chloride, hydroxide, and nitrate are water-soluble, whereas barium arsenate, chromate, duoride, oxalate, and sulfate are not. Most water-insoluble barium salts dissolve in dilute acids barium sulfate, however, requkes strong sulfuric acid. 

Ce(III) forms a water-insoluble hydroxide, carbonate, oxalate, phosphate, and fluoride sparingly soluble sulfate and acetate and soluble nitrate and chloride (and bromide). In solution the salts are only slightly hydrolyzed. The carbonate is readily prepared and is a convenient precursor for the preparation of other derivatives. The sparingly soluble sulfate and acetate decrease in solubihty with an increase in temperature. Calcination of most Ce(III) salts results in Ce02. 

Most lanthanide compounds are sparingly soluble. Among those that are analytically important are the hydroxides, oxides, fluorides, oxalates, phosphates, complex cyanides, 8-hydroxyquinolates, and cup-ferrates. The solubility of the lanthanide hydroxides, their solubility products, and the pH at which they precipitate, are given in Table 2. As the atomic number increases (and ionic radius decreases), the lanthanide hydroxides become progressively less soluble and precipitate from more acidic solutions. The most common water-soluble salts are the lanthanide chlorides, nitrates, acetates, and sulfates. The solubilities of some of the chlorides and sulfates are also given in Table 2. 

Nickel is a silver-white, lustrous, hard, malleable, ductile, ferromagnetic metal that is relatively resistant to corrosion and is a fair conductor of heat and electricity. Nickel is a ubiquitous trace metal that occurs in soil, water, air, and in the biosphere. The average content in the earth s crust is about 0.008%. Nickel ore deposits are accumulations of nickel sulfide minerals (mostly pentlandite) and laterites. Nickel exists in five major forms elemental nickel and its alloys inorganic, water-soluble compounds (e.g., nickel chloride, nickel sulfate, and nickel nitrate) inorganic, water-insoluble compounds (e.g., nickel carbonate, nickel sulfide, and nickel oxide) organic, water-insoluble compounds and nickel carbonyl Ni(CO). ... 

The physical and chemical properties of elemental thorium and a few representative water soluble and insoluble thorium compounds are presented in Table 3-2. Water soluble thorium compounds include the chloride, fluoride, nitrate, and sulfate salts (Weast 1983). These compounds dissolve fairly readily in water. Soluble thorium compounds, as a class, have greater bioavailability than the insoluble thorium compounds. Water insoluble thorium compounds include the dioxide, carbonate, hydroxide, oxalate, and phosphate salts. Thorium carbonate is soluble in concentrated sodium carbonate (Weast 1983). Thorium metal and several of its compounds are commercially available. No general specifications for commercially prepared thorium metal or compounds have been established. Manufacturers prepare thorium products according to contractual specifications (Hedrick 1985). 

Holmium forms all its compounds in -i-3 valence state. The metal forms fluoride, hydroxide, phosphate, oxalate, and carbonate that are insoluble in water. Its water-soluble salts are chloride, bromide, iodide, acetate, nitrate and sulfate. 

Mercury is most accurately determined by the cold vapor atomic absorption spectroscopic method. The instrument is set at the wavelength 253.7 nm. The metal, its salts and organic derivatives in aqueous solution can be measured by this method. The solution or the solid compounds are digested with nitric acid to convert into water-soluble mercury(ll) nitrate, followed by treatment with potassium permanganate and potassium persulfate under careful heating. The excess oxidants in the solution are reduced with NaCl-hydroxylamine sulfate. The solution is treated with stannous chloride and aerated. The cold Hg vapor volatdizes into the absorption cell where absorbance is measured. 

Common water-soluble salts include the sulfate, selenate, nitrate, and perchlorate, all of which are hydrolyzed in aqueous solution. Double salts are formed readily by the. sulfate and by the chloride. 

Organic carbon (OC) and elemental carbon (EC) concentrations in smoke aerosol can be measured by using a semicontinuous thermal-optical OC/EC instruments [18]. Water-soluble organic carbon (WSOC) and water-soluble ions can be detected in smoke plumes with a PILS combined with a total organic carbon analyzer [30] and IC [19]. Besides smoke-specific tracers, the HR-ToF-AMS enables to study the concentrations of organic matter (OM), nitrate, ammonium, sulfate, and chloride in smoke particles [30]. Black carbon (BC) can be measured in real-time with several instruments, e.g., with aethalometer [19], multi-angle absorption photometer [29], and particle soot absorption photometer [25]. 

The chloride, bromide, bromate, perchlorate, nitrate, acetate, and iodide salts are all soluble in water, the sulfates sparingly soluble, and the fluorides, carbonates, oxalates, and phosphates insoluble. 

The known inorganic chemistry of radium does not differ significantly from that of barium. The isotopes of radium are compiled in Table 4. The chloride, bromide, and nitrate salts of Ra are all water soluble. For example, RaCb (24.5 g/lOOmL H2O at 25 °C) has a comparable solubility to BaCl2 (30.7 g). This slight difference is the primary mode of separation of Ra from Ba. Barium sulfate frequently plays the role of a carrier for Ra. The solubility of RaS04 (2.1 x 10 " g/lOOmL H2O at 25 °C) is perhaps the lowest of any of the group 2 elements. Other aqueous insoluble salts of Ra include and Cr04. ... 

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