Sulfates iron oxide

Environment Electrostatic precipitator receives air from steel blast furnace 50-180°F (10-82°C) high moisture, chlorides, sulfides and sulfate, iron oxides... 

By bacterial disproportionation H S and are produced concurrently without participation of an external electron acceptor or donor (Bak and Pfennig 1987 Thamdrup et al. 1993). The biogeo-chemical transformations of sulfur in marine sediments are closely coupled to the cycles of iron and manganese. Sulfate, iron oxides, and manganese oxides all serve as electron acceptors in the respiratory degradation of organic matter. As there are also non-enzymatic reactions between iron, manganese and H S within the sediment, the quantification of dissimilatoiy, heterotrophic Fe and Mn reduction is particularly difficult. 

The yield of hydroquinone is 85 to 90% based on aniline. The process is mainly a batch process where significant amounts of soHds must be handled (manganese dioxide as well as metal iron finely divided). However, the principal drawback of this process resides in the massive coproduction of mineral products such as manganese sulfate, ammonium sulfate, or iron oxides which are environmentally not friendly. Even though purified manganese sulfate is used in the agricultural field, few solutions have been developed to dispose of this unsuitable coproduct. Such methods include MnSO reoxidation to MnO (1), or MnSO electrochemical reduction to metal manganese (2). None of these methods has found appHcations on an industrial scale. In addition, since 1980, few innovative studies have been pubUshed on this process (3). 

Synthetic Iron Oxides. Iron oxide pigments have been prepared synthetically since the end of the seventeenth century. The first synthetic red iron oxide was obtained as a by-product of the production of sulfuric acid from iron sulfate containing slate. Later, iron oxide pigments were produced direcdy by the thermal decomposition of iron sulfates. In the 1990s, about 70% of all iron oxide pigments consumed are prepared synthetically. 

The largest volume of synthetic red iron oxide is produced by the two-step calcination of iron(II) sulfate. In the first step, the iron(II) sulfate heptahydrate is dehydrated to a monohydrate ... 

Iron oxide yellows can also be produced by the direct hydrolysis of various ferric solutions with alkahes such as NaOH, Ca(OH)2, and NH. To make this process economical, ferric solutions are prepared by the oxidation of ferrous salts, eg, ferrous chloride and sulfate, that are available as waste from metallurgical operations. The produced precipitate is washed, separated by sedimentation, and dried at about 120°C. Pigments prepared by this method have lower coverage, and because of their high surface area have a high oil absorption. 

In another process, strontium sulfate can be converted to strontium carbonate direcdy by a metathesis reaction wherein strontium sulfate is added to a solution of sodium carbonate to produce strontium carbonate and leave sodium sulfate in solution (6). Prior to this reaction, the finely ground ore is mixed with hydrochloric acid to convert the calcium carbonates and iron oxides to water-soluble chlorides. 

Other reactions taking place throughout the hardening period are substitution and addition reactions (29). Ferrite and sulfoferrite analogues of calcium monosulfoaluminate and ettringite form soHd solutions in which iron oxide substitutes continuously for the alumina. Reactions with the calcium sihcate hydrate result in the formation of additional substituted C—S—H gel at the expense of the crystalline aluminate, sulfate, and ferrite hydrate phases. 

Other countries have similar types, some classifications, as in Germany, are based on age-strength levels by standard tests (70). A product made in Italy and Prance known as Perrari cement is similar to Type V and is sulfate-resistant. Such cements have high iron oxide and low alumina contents, and harden more slowly. 

Iron oxides are stable pigments iasoluble ia most solvents but usually soluble ia hydrochloric acid. Those not soluble ia HCl can be fused with potassium hydrogen sulfate, KHSO, and then dissolved ia water. 

The foHowing factors are important in dump leaching (/) the role of bacteria (2) the appHcation of acid to prevent or delay precipitation of hydrated ferric sulfate (J) oxidation to remove excess iron from mine water in settling pools, as shown in equations 38 and 39 (4) optimization of dump configuration for good solution distribution and (5) avaHabHity of oxygen. 

Ethylamines. Mono-, di-, and triethylamines, produced by catalytic reaction of ethanol with ammonia (330), are a significant outlet for ethanol. The vapor-phase continuous process takes place at 1.38 MPa (13.6 atm) and 150—220°C over a nickel catalyst supported on alumina, siUca, or sihca—alumina. In this reductive amination under a hydrogen atmosphere, the ratio of the mono-, di-, and triethylamine product can be controlled by recycling the unwanted products. Other catalysts used include phosphoric acid and derivatives, copper and iron chlorides, sulfates, and oxides in the presence of acids or alkaline salts (331). Piperidine can be ethylated with ethanol in the presence of Raney nickel catalyst at 200°C and 10.3 MPa (102 atm), to give W-ethylpiperidine [766-09-6] (332). 

Aluminium fluoride (anhydrous) [7784-18-4] M 84.0, m 250°. Technical material may contain up to 15% alumina, with minor impurities such as aluminium sulfate, cryolite, silica and iron oxide. Reagent grade AIF3 (hydrated) contains only traces of impurities but its water content is very variable (may be up to 40%). It can be dried by calcining at 600-800° in a stream of dry air (some hydrolysis occurs), followed by vacuum distn at low pressure in a graphite system, heated to approximately 925° (condenser at 900°) [Henry and Dreisbach J Am Chem Soc 81 5274 1959]. 

The principal constituents of the paniculate matter are lead/zinc and iron oxides, but oxides of metals such as arsenic, antimony, cadmium, copper, and mercury are also present, along with metallic sulfates. Dust from raw materials handling contains metals, mainly in sulfidic form, although chlorides, fluorides, and metals in other chemical forms may be present. Off-gases contain fine dust panicles and volatile impurities such as arsenic, fluorine, and mercury. 

Most black pigments are made of carbon black formed by depositing carbon from a smoky flame of natural gas on a metal surface. Lampblack is made similarly by burning oik Bone blacks are made from charred bones. Graphite occurs naturally or can be prepared from coal in electric furnaces. Mineral blacks come from shale, peat, and coal dust. Iron oxide blacks are found in nature or prepared. Blue lead sulfate is a pigment for priming. Of these, carbon black is su[XTinr. 

Eisenoxydul-hydrat, n. ferrous hydroxide, iron(ll) hydroxide, -oxyd, n. ferrosoferric oxide, iron(II,III) oxide, magnetic iron oxide (FeaOi). -salz, n. ferrous salt, iron(II) salt, -sulfat, n. ferrous sulfate, iron(II) sulfate, -verbindung, /. ferrous compound, iron(ll) compound. 

Some acrylic acid copolymers are promoted as having a very wide range of functions that permit them to act as calcium phosphate DCAs, barium sulfate antiprecipitants, particulate iron oxides dispersants, and colloidal iron stabilizers. One such popular copolymer is acrylic acid/sulfonic acid (or acrylic acid/ 2-acrylamido-methylpropane sulfonic acid, AA/SA, AA/AMPS). Examples of this chemistry include Acumer 2000 (4,500 MW) 2100 (11,000 MW) Belclene 400, Acrysol QR-1086, TRC -233, and Polycol 43. 

The abiotic rate of the first oxidation reaction is slow the rate of the second reaction increases with increasing pH. The second iron oxidation reaction produces Fe(OH)3(s), ferric hydroxide. "Yellow boy," a limonitic precipitate, is produced when the ferric hydroxide mixes with ferric sulfates when formed, "Yellow boy" gives receiving waters an unappealing yellow tint. 

Hence, in the absence of a redox system in solution the anodic reaction of FeS2 yields iron oxide/hydroxide and water-soluble sulfate ions. The compound does not undergo non-oxidative dissolution. 

Fig. 2.43. Graphical illustration of sulfur isotope values of HiS (left axis and. solid line) produced during basalt-seawater interaction at various water/rock ratios. Calculations assume that seawater sulfate is mostly removed as anhydrite, that any residual sulfate is reduced by iron oxidation in reacting basalt, and that there is quantitative leaching of basaltic sulfide and homogeneous mixing of both sulfides. Dashed line...

The scale may consist of calcium carbonate, barium sulfate, gypsum, strontium sulfate, iron carbonate, iron oxides, iron sulfides, and magnesium salts [943]. There are monographs (e.g.. Corrosion and Scale Handbook [159]) and reviews [414] on scale depositions available in the literature. 

The scheme F involves sulphating roasting. The conditions are so chosen that iron is converted to its oxidic form (Fe203) while nickel and copper are converted to nickel sulfate and copper sulfate respectively. The product is subsequently water leached to take the sulfates into solution, leaving the iron oxide in the leach residue. 

Leblanc wrestled with the problem for five years between 1784 and 1789. Then finally, somehow, someway, he stumbled on the solution. Ancient ironmakers had used carbon in the form of charcoal when hot, the carbon is highly reactive and wrests the oxygen from iron oxide ores. As Leblanc heated his sodium sulfate with charcoal, he added a key new ingredient—common limestone (chalk)—as his source of C03. Almost miraculously, the transformation took place ... 

Primary copper processing results in air emissions, process wastes, and other solid-phase wastes. Particulate matter and sulfur dioxide are the principal air contaminants emitted by primary copper smelters. Copper and iron oxides are the primary constituents of the particulate matter, but other oxides, such as arsenic, antimony, cadmium, lead, mercury, and zinc, may also be present, with metallic sulfates and sulfuric acid mist. Single-stage electrostatic precipitators are widely used in the primary copper industry to control these particulate emissions. Sulfur oxides contained in the off-gases are collected, filtered, and made into sulfuric acid. 

In sulfuric acid pickling, ferrous sulfate is formed from the reaction of iron oxides with sulfuric acid ... 

---