Abstract: A method for producing an alkaline earth metal borate dispersion, comprising two steps of:(I) reacting at 20.degree.-100.degree. C. a mixture of the following ingredients (A) to (E)(A) 100 parts by weight of the oil-soluble neutral sulfonate of an alkaline earth metal,(B) 10-100 parts by weight of the hydroxide or oxide of an alkaline earth metal,(C) boric acid in an amount which is 0.5-6.5 times in mol that of the ingredient (B),(D) 5-50 parts by weight of water, and(E) 50-200 parts by weight of a dilution solvent and then(II) heating the reslting reaction mixture to 100.degree.-200.degree. C. to remove the water and a part of the dilution solvent as required.

Abstract: A method of preventing corrosion of steelworks by a flowing corrosive solution having a pH of 6.7 to 7.1 and comprising water, ammonia in a concentration of from 0.5 to 4 mols per liter of solution and hydrogen sulfide in a concentration of from 5 to 15 kg/cm.sup.2 as its partial pressure in the vapor phase, said corrosive solution contacting said steelwork at a flow velocity of from 1 to 10 meters per second by adding at least one substance selected from the group consisting of elemental sulfur, ammonium polysulfide and alkali polysulfide to said corrosive solution in an amount of 74-200 ppm as the amount of available sulfur.