An aqueous synthetic acid composition for use in oil industry activities, said composition comprising: lysine and hydrogen chloride in a molar ratio ranging from 1:3 to 1:12.5, preferably from more than 1:5 to 1:8.5; it can also further comprise a metal iodide or iodate; an alcohol or derivative thereof Said composition demonstrates advantageous properties over known synthetic acids at temperatures above 90 C. Said composition is useful in various oil and gas industry operations. Preferred embodiments of said composition providing substantial advantages in matrix acidizing by increasing the effectiveness of wormholing compared to conventional mineral acids such as HCl.

A method for inhibiting corrosion on a steel surface by treatment with a solution comprising a citrus leaf extract and a leaf extract from a second plant is described. The citrus leaf extract may be from a Citrus x limon (lemon) plant, and the second leaf extract may be from a saffron plant, an almond plant, a Psidium guajava plant, or an Origanum majorana plant. Methods of making and applying the leaf extracts to steel are discussed, as well as the electrochemical properties and corrosion inhibition of treated steel in the presence of a corrosive agent.

An aqueous iron sulfide dissolver including zinc, chromium, a methoxybenzoic acid, formic acid, acetic acid, and hydrochloric acid. The iron sulfide dissolver is made by combining these components, and dissolves compounds including iron sulfide upon contact. Evolved hydrogen sulfide reacts with the methoxybenzoic acid to yield solubilized methanethiol as an intermediate product, which is further oxidized to yield dissolved dimethyl disulfide.

An additive comprising glucaric acid and/or glucaric acid salt may be added to an aqueous system in an effective amount to remove rust from a corroded metallurgy and inhibit further rust formation and/or corrosion of the metallurgy within the aqueous system, and also to passivate any metallurgy within an aqueous system, wherein the additive may not contain a phosphorous compound or an iron activating agent. The aqueous system may be an aqueous stream, a hydrocarbon stream containing water, a cooling tower, a boiler, a cooling water system, and combinations thereof.

An aqueous cleaning solution for removing rouging deposits on media-contacted surfaces of stainless steels comprises a first component and a second component. The first component is an alkali sulfite and the second component is an alkali formate, wherein the concentrations thereof are adjusted in such manner that formate is present in a molar ratio of 1.5 to 4.2 relative to sulfite, and that the pH value of the cleaning solution is 4.0 to 4.8. For preparing the aqueous cleaning solution, an aqueous solution of an alkali hydroxide is provided initially, thereafter a first amount of concentrated aqueous formic acid is admixed in an excess in such manner that a pH value of 3.5 to 4.5 is established, then a second amount of solid alkali sulfite is admixed in accordance with the sulfite concentration to be established, thus resulting in a pH value of 5.5 to 6.5, and finally a third amount of concentrated aqueous formic acid is admixed until a pH value of 4.0 to 4.8 is attained.

Various compositions and methods are disclosed for treatment of heat tints on stainless steel surfaces that allow for simultaneous pickling and passivation of stainless steel. Moreover, contemplated compositions and methods are free or substantially free of hydrofluoric acid and can be applied in various forms at different temperatures. In further preferred aspects of the inventive subject matter, the compositions contemplated herein include magnesium salts of acids, and especially magnesium salts of hydrofluoric and nitric acid, most typically in an aqueous base. Such compositions are significantly safer for a user and disposal. Where desired, additional ingredients may be added, including surfactants, chelators, thickeners, and/or fillers.

Provided is an acid-pickling additive for a surface oxide scale of a stainless steel material, a preparation method thereof and an acid-pickling method. The acid-pickling additive consists of 1 to 10 parts by weight of an alcohol amine compound, 0.1 to 5 parts by weight of a metal complex ligand, 0 to 10 parts by weight of a nitrogen-containing organic cyclic compound, 0 to 3 parts by weight of an alcohol compound, 0 to 3 parts by weight of a plant extract, and 1 to 2 parts by weight of water. This acid-pickling additive can solve the problems of high energy consumption, environmental pollution, and high cost in the existing method for removing an oxide scale of a stainless steel.

A treatment liquid is a treatment liquid for a semiconductor device, containing a fluorine-containing compound, a corrosion inhibitor, and calcium, in which the mass content ratio of the calcium to the fluorine-containing compound in the treatment liquid is 1.0?10.sup.?10 to 1.0?10.sup.?4.

A low-corrosivity composition suitable for dissolving scale on metals. The scale includes iron sulfide scale. The composition includes an aqueous hydrogen peroxide solution comprising hydrogen peroxide; and an acidic solution comprising at least one acid, where the hydrogen peroxide and acid are present at concentrations such that the hydrogen peroxide does not break down to form visible bubbles at about room temperature, where the hydrogen peroxide and acid are present at concentrations such that iron sulfide scale is removed from a metal with iron sulfide scale, after the composition contacts the metal and iron sulfide scale at an elevated temperature greater than room temperature, and where the hydrogen peroxide and acid are present at concentrations such that pitting is not caused on the metal, the metal comprising carbon steel.

An aqueous cleaning solution for removing rouging deposits on media-contacted surfaces of stainless steels comprises a first component and a second component. The first component is an alkali sulfite and the second component is an alkali formate, wherein the concentrations thereof are adjusted in such manner that formate is present in a molar ratio of 1.5 to 4.2 relative to sulfite, and that the pH value of the cleaning solution is 4.0 to 4.8. For preparing the aqueous cleaning solution, an aqueous solution of an alkali hydroxide is provided initially, thereafter a first amount of concentrated aqueous formic acid is admixed in an excess in such manner that a pH value of 3.5 to 4.5 is established, then a second amount of solid alkali sulfite is admixed in accordance with the sulfite concentration to be established, thus resulting in a pH value of 5.5 to 6.5, and finally a third amount of concentrated aqueous formic acid is admixed until a pH value of 4.0 to 4.8 is attained.