GB396053A - Improvements relating to the pickling of metals - Google Patents

Abstract

A substance for use as a restrainer in the pickling of iron or steel or as an ingredient in a material for cleaning iron or steel prior to painting, is prepared by heating with sulphur a mix whose predominating constituents are homologues of pyridine and quinoline, separately or admixed together in any proportion, but which may also contain other cyclic nitrogenous bases, such as piperidine bases or the dipiperidyls. Or such a mix may be heated with sulphur chloride to give a sulphurated product. It is preferred to use a mix commercially known as heavy pyridine bases, and consisting essentially of the higher homologues of pyridine boiling above 160 DEG C. which are extracted from tar distillates by acid treatment. When using sulphur heating may take place at temperatures of 130 DEG C. and upwards; when using sulphur chloride the more violent reaction may be modified by the presence of diluents such as benzene or paraffin hydrocarbons. In an example heavy pyridine bases boiling between 155-205 DEG C. (95 per cent between 160-205 DEG C.) are heated with sulphur at 135 DEG C. for 20-25 hours. The sulphurized product is mixed with an equal volume of sulphuric acid, impurities which separate are removed, and the liquid then blown with steam. The product so obtained may be used with or without dilution as a restrainer in a pickling bath. Casein, glue, size, sulphite cellulose lye, &c. may be p added to produce a frothing restrainer which decreases acid spray and facilitates subsequent removal of dirt from the metal. For treating iron or steel prior to painting the sulphurated base is added together with one or more organic solvents to an acid such as phosphoric acid. A composition consisting of phosphoric acid, sulphurated base, furfural and industrial spirit is specified for this purpose.ALSO:A substance for use as an ingredient in a material for cleaning iron or steel prior to painting, is prepared by heating with sulphur or sulphur chloride a mix whose predominating constituents are homologues of pyridine and quinoline, separately or admixed together in any proportion, but which may also contain other cyclic nitrogenous bases, such as piperidine bases or the dipiperidyls. It is preferred to use a mix commercially known as heavy pyridine bases, and consisting essentially of the higher homologues of pyridine boiling above 160 DEG C. which are extracted from tar distillates by acid treatment. When using sulphur heating may take place at temperatures of 130 DEG C. and upwards; when using sulphur chloride the more violent reaction may be modified by the presence of diluents such as benzene or paraffin hydrocarbons. In an example heavy pyridine bases boiling between 155-205 DEG C. (95 per cent between 160-205 DEG C.) is heated with sulphur at 135 DEG C. for 20-25 hours. The sulphurized product is mixed with an equal volume of sulphuric acid, impurities which separate are removed, and the liquid then blown with steam. The product so obtained may be used with or without dilution as a restrainer in a pickling bath. Casein, glue, size, sulphite, cellulose, lye, &c. may be added to produce a frothing restrainer which reduces acid spray and facilitates subsequent removal of dirt from the metal. For treating iron or steel prior to painting the sulphurized base is added together with one or more organic solvents to an acid such as phosphoric acid. A composition consisting of phosphoric acid, sulphurated base, furfural and industrial spirit is specified for this purpose.ALSO:A substance for use as a restrainer in the pickling of iron or steel or as an ingredient in a material for cleaning iron or steel prior to painting, is prepared by heating with sulphur a mix whose predominating constituents are homologues of pyridine and quinoline, separately or mixed together in any proportion, but which may also contain other cyclic nitrogenous bases, such as piperidine bases or the dipiperidyls. Or such a mix may be heated with sulphur chloride to give a sulphurated product. It is preferred to use a mix commercially known as heavy pyridine bases, and consisting essentially of the higher homologues of pyridine boiling above 160 DEG C. which are extracted from tar distillates by acid treatment. When using sulphur heating may take place at temperatures of 130 DEG C. and upwards; when using sulphur chloride the more violent reaction may be modified by the presence of diluents such as benzene or paraffin hydrocarbons. In an example heavy pyridine bases boiling between 155-205 DEG C. (95 per cent between 160-205 DEG C.) is heated with sulphur at 135 DEG C. for 20-25 hours. The sulphurized product is mixed with an equal volume of sulphuric acid, impurities which separate are removed, and the liquid then blown with steam. The product so obtained may be used with or without dilution as a restrainer in a pickling bath. Casein, glue, size, sulphite cellulose lye, &c. may be added to produce a frothing restrainer which decreases acid spray and facilitates subsequent removal of dirt from the metal. For treating iron or steel prior to painting the sulphurated base is added together with one or more organic solvents to an acid such as phosphoric acid. A composition consisting of phosphoric acid sulphurated base, furfural and industrial spirit is specified for this purpose.