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Subject: heel chem. Добрый день! перевожу патент и затрудняюсь подобрать точный термин к следующему выражению - heel solution. Мне понятно, что это за раствор, только вот как бы это назвать по-русски-то, не знаю (начальный раствор, расвор - основание ???). Заранее спасибо всем, кто откликнется. Контекст:A silica sol is prepared by diluting com¬mercial sodium silicate having a SiO2:Na2O mole ratio of 3.36 with water such that the SiO2 content is 40 grams per liter of solution. This solution is heated to a tem¬perature of 95° C. A solution of dilute sulfuric acid (about 4.7 grams of H2SO4/100 ml.) is then added over a period of about 2 hours at a uniform rate, one vol¬ume of acid solution being added for about 3 volumes of silicate. The concentration of the acid is so regulated that about 80 percent of the Na2O in the silicate is neu¬tralized. The sodium ion concentration should be 0.3 normal. The final pH of the silica sol is about 10.2.
The particles of colloidal silica are dense, spherical, relatively uniform in size and have an average diameter of about 21 millimicrons. They are discrete, separate and non-aggregated.
Two and one-half liters of 3 percent silica sol pre¬pared as above-described are diluted with two and one-half liters of water. This sol, which contains 1.5% SiO2 consisting of discrete dense spherical silica particles hav¬ing an average diameter of 21 millimicrons, will here¬after be referred to as the "heel."
To 2500 ml. of the heel there are added simultane¬ously but separately and at a substantially uniform rate over a period of 2 hours, 1500 ml. of sodium silicate solution made by diluting 252 grams of a commercial sodium silicate solution with water to a SiO2 content of 5 grams per 100 ml. (0.833 mol per liter), 2000 ml. of a sulfuric acid solution containing 46 grams of 95.5% H2SO4, and a sodium aluminate solution prepared by dissolving 66 grams of sodium aluminate in 1.5 liters of water. The reaction mixture is maintained at a tem¬perature of about 95° C. during the entire process and within a pH range of from 10.0 to 11.1, the pH at the end of cycle being 10.52. In order to maintain this pH range it is necessary to add only about 60% of the sul¬furic acid calculated to be equivalent to the total Na2O, Very vigorous agitation is provided in the reaction zone.
The product resulting from the process is a sol.
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