Ferrous selenate

Ferrous selenate can be prepared by the action of selenie acid on ferrous sulphide selenie acid does not dissolve iron (see p. 335) ... [Pg.337]

The production of the hydrogen sulphide serves to prevent the selenate being oxidised to the ferric state. There may also be a slight secondary reaction resulting in the precipitation of both sulphur and selenium according to the equation on p. 335. From the solution unstable monoclinic crystals of hydrated ferrous selenate, FeSe04.7H20, may be deposited. [Pg.337]

Selenic acid dissolves iron with the production of ferrous selenate, FeSe04, and a deposit of selenium which collects on the surface of the undissolved metal, thereby greatly retarding the reaction. No hydrogen is evolved, and the selenium is presumably obtained by the action of nascent hydrogen upon the excess of selenic acid. Thus —... [Pg.53]

Ferrous sdenate, FeSe04.—Iron dissolves in aqueous selenic acid, yielding ferrous selenate and a deposit of selenium,7 which collects upon the surface of the undissolved metal and shields it from further attack. The rate of solution is thereby so greatly retarded that as a method of preparing ferrous selenate it is not to be recommended.8 The net result of the action may be represented by the equation —... [Pg.169]

Ferrous carbonate is likewise but slowly attacked by selenic acid a better method of preparing ferrous selenate consists in dissolving ferrous sulphide in a concentrated solution of the acid.1 The hydrogen sulphide evolved reduces a portion of the selenic acid in accordance with the equation —... [Pg.170]

Ferrous selenate yields double selenates with salts of the alkali metals. Their general formula is —... [Pg.170]

Potassium ferrous selenate, K2Se04.FeSe04.6H20. [Pg.170]

Rubidium ferrous selenate, Rb2Se04.FeSe04.6H20. [Pg.170]

Caesium ferrous selenate, Cs2Se04.FeSe04.6H20. [Pg.170]

Ammonium ferrous selenate, (NH4)2SeO4.FeSeO4.0H2O. [Pg.170]

In mineral technology, sulfur dioxide and sulfites are used as flotation depressants for sulfide ores. In electrowinning of copper from leach solutions from ores containing iron, sulfur dioxide prereduces ferric to ferrous ions to improve current efficiency and copper cathode quaHty. Sulfur dioxide also initiates precipitation of metallic selenium from selenous acid, a by-product of copper metallurgy (326). [Pg.148]

White, A.F. (1990) Hetero electrochemical reactions associated with oxidation of ferrous oxide and selenate surfaces. In Hochella,... [Pg.643]

Iron Selenites.—Although metallic iron does not appear to be soluble in selenous acid, yet selenites of iron are readily obtained in a variety of ways. When sodium selenite is added to ferrous sulphate solution, a white precipitate of ferrous selenite, FeSe03, is obtained.4 This becomes darker on exposure to air in consequence of oxidation. If the white precipitate is dissolved in hydrochloric acid, a portion of the selenium separates out, whilst ferric chloride and selenous acid remain in solution. Thus —... [Pg.169]

The efficacy of these reactions in wastewater treatment system remains doubtful, however. The reduction of selenate by ferrous sulfide is deemed to be important in wastewater treatment systems and can result in the formation of highly insoluble ferrohydroxy selenite, the solubility product of which has been estimated to be 10 (Geering et ai, 1968) ... [Pg.227]

In acid solution, ferrous salts act as reductants. This effect can be enhanced by the addition of concentrated phosphoric acid which forms the complex Fe(P04)2 ion with the Fe+ ions that are produced when Fe+ ions enter into redox reactions. This enhancement of the redox potential of the Fe+ ion can be employed for the rapid detection of salts of noble metals, selenic and selenious acid and also telluric and tellurous acid. [Pg.86]

Selenites and selenates are quantitatively reduced to elementary selenium when their acid solutions are warmed with ferrous sulfate. In contrast, tellurite and tellurate solutions remain unaltered because the redox potential of iron is not sufhcient to accomplish the reaction Fe i + Teiv(vi) Fe -f Te°. However, the reducing power of Fe+ ions can be raised considerably if the Fe+ ions are removed as soon as they are produced. Phosphoric acid is excellent for this purpose it immediately converts the Fe+ ions into [Fe(P04)2] " ions. Fluorides act analogously through the formation of [FeF,]- ions. Consequently, when tellurites or tellurates are warmed with a ferrous sulfate-phosphoric acid mixture there is complete reduction to free tellurium. [Pg.472]

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