Described herein is an aqueous composition for removing cryolitic deposits from plants or parts of plants which serve for the conversion treatment of metal surfaces, said composition including a) at least one mineral acid, and b) at least one dicarboxylic acid of the formula HOOC—(CH.sub.2).sub.x—COOH, where x is 0 to 3 and no borate-containing compounds have been added to the composition. Also described herein is a corresponding method for removing cryolitic deposits.

An aqueous synthetic acid composition is provided for use in oil industry activities. The composition comprises: 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. The composition may further comprise a metal iodide or iodate and an alcohol or derivative thereof. The composition demonstrates advantageous properties for synthetic acids at temperatures above 90° C. The composition is useful in various oil and gas industry operations. Preferred embodiments of the composition provide substantial advantages in matrix acidizing by increasing the effectiveness of wormholing.

An aqueous synthetic acid composition is provided for use in oil industry activities. The composition comprises: 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. The composition may further comprise a metal iodide or iodate and an alcohol or derivative thereof. The composition demonstrates advantageous properties for synthetic acids at temperatures above 90° C. The composition is useful in various oil and gas industry operations. Preferred embodiments of the composition provide substantial advantages in matrix acidizing by increasing the effectiveness of wormholing.

A method for removing a metal compound capable of selectively removing an oxide of a metal, a nitride of a metal, or an oxynitride of a metal while suppressing the removal of silicon dioxide, silicon nitride, polysilicon, a simple substance of a metal, or the like. The method includes bringing at least one metal compound selected from oxides of a metal, nitrides of a metal, and oxynitrides of a metal into contact with a treatment liquid to remove it from a treatment object. The metal is at least one selected from tungsten, cobalt, nickel, tantalum, titanium, iron, copper, and molybdenum. The treatment liquid is an aqueous solution containing at least one compound for removal selected from carboxylic acids and salts thereof and contains the compound(s) for removal at a total concentration of 2 mass % or more.

A composition includes a polymer and a solvent. The polymer includes a group (X) which is at least one selected from the group consisting of: a group including at least two cyano groups; a group including —B(OR).sub.2; a group including —PO(OR).sub.2; and a group including —P(OR).sub.2. Each R independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. The polymer preferably includes the group (X) at an end of a main chain thereof or at an end of a side chain thereof.

A composition includes a polymer and a solvent. The polymer includes a group (X) which is at least one selected from the group consisting of: a group including at least two cyano groups; a group including —B(OR).sub.2; a group including —PO(OR).sub.2; and a group including —P(OR).sub.2. Each R independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. The polymer preferably includes the group (X) at an end of a main chain thereof or at an end of a side chain thereof.

A chemical decontamination reagent containing a reducing agent, a reductive metal ion, and an inorganic acid is provided to remove a radioactive oxide layer on a metal surface. The reagent can dissolve the radioactive oxide layer on the metal surface effectively at a relatively low temperature and enables a simple process of contacting the reagent to the radioactive oxide, thus economically effective in terms of cost and time required for the process. Since the decontamination does not use a conventional organic chelating agent such as oxalic acid, but the reducing agent as a main substance, the residuals of the reducing agent remained after decontamination can be decomposed and removed with an oxidizing agent. Due to the easy decomposition with the chemical decontamination reagent, secondary wastes can be minimized and the radionuclides remained in the decontamination reagent solution can be removed effectively.

A chemical decontamination reagent containing a reducing agent, a reductive metal ion, and an inorganic acid is provided to remove a radioactive oxide layer on a metal surface. The reagent can dissolve the radioactive oxide layer on the metal surface effectively at a relatively low temperature and enables a simple process of contacting the reagent to the radioactive oxide, thus economically effective in terms of cost and time required for the process. Since the decontamination does not use a conventional organic chelating agent such as oxalic acid, but the reducing agent as a main substance, the residuals of the reducing agent remained after decontamination can be decomposed and removed with an oxidizing agent. Due to the easy decomposition with the chemical decontamination reagent, secondary wastes can be minimized and the radionuclides remained in the decontamination reagent solution can be removed effectively.

An aqueous synthetic acid composition is provided for use in oil industry activities The composition comprises: 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 The composition may further comprise a metal iodide or iodate and an alcohol or derivative thereof. The composition demonstrates advantageous properties for synthetic acids at temperatures above 90° C. The composition is useful in various oil and gas industry operations. Preferred embodiments of the composition provide substantial advantages in matrix acidizing by increasing the effectiveness of wormholing.

An aqueous synthetic acid composition is provided for use in oil industry activities The composition comprises: 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 The composition may further comprise a metal iodide or iodate and an alcohol or derivative thereof. The composition demonstrates advantageous properties for synthetic acids at temperatures above 90° C. The composition is useful in various oil and gas industry operations. Preferred embodiments of the composition provide substantial advantages in matrix acidizing by increasing the effectiveness of wormholing.