Assertion: hydrocyanic acid | /r/AtLocation | the sulphate
Facets:
Source sentences:
text: A process of making a crystalline leuco ferrous-ferrocyanide salt of an alkaline reacting substance, suitable for oxidation to blue pigment, comprising mixing aqueous suspensions of hydrocyanic acid, an alkaline reacting substance, and ferrous sulphate, a pH of between 3.5 to 5.5 being maintained substantially until the reaction is completed, the reaction being carried out in a non-oxidizing atmosphere, the alkaline reacting substance being at least one compound taken from the group consisting of alkali and alkaline earth metal and ammonium hydroxides, carbonates, acetates, amines, and quaternary ammonium bases, the recited pH being maintained by mixing predetermined concentrations of aqueous solutions of each of the substances in the proportions required .to maintain said pH, the hydrocyanic acid being added to the sulphate not later than the alkaline reacting substance is added, the alkaline reacting substance being added together with or after the ferrous sulphate is added, so that the required acidity is developed by setting free H 80 from the ferrous sulphate, the alkaline reacting substance being employed in a total amount to obtain the following ratio in the product: lAlk:1Fe:3CN, in which Alk signifies the NH,+ chemical equivalent of the cation of the alkaline reacting substance, the molar ratio of the reactants being in the range 3.5 to 2.9 HCN:4.1 to 2.2 alkaline reacting substance:1FeSO the larger proportions of alkaline reacting substance being employed of the less basic members of said group.
text: The process of making a pigment, comprising mixing aqueous suspensions of hydrocyanic acid, an alkaline re acting substance, and ferrous sulphate, a pH of between 3.5 to 5.5 being maintained substantially until the reaction is completed, the reaction being carried out in a nonoxidizing atmosphere, the alkaline reacting substance being taken from the group consisting of alkali and alkaline earth metal and ammonium hydroxides, carbonates, ace tates, amines, and quaternary ammonium bases, the recited pH being maintained by mixing predetermined concentrations of aqueous solutions of each of the substances in the proportions required to maintain said pH, the hydrocyanic acid being added to the sulphate not later than the alkaline reacting substance is added, the alkaline reacting substance being added together With or after the ferrous sulphate is added, so that the required acidity is developed by setting free H (from the ferrous sulphate, the alkaline reacting substance being employed in a total amount to obtain the following ratio in the product: