method for the production of sulphuric acid and calcium carbonate caldioNALDI GIOVANNI
Leaching of the saprolitic laterite material by sulphuric acid at atmospheric pressure shows that nickel in lizardite is loosely bound within the octahedral layer and as much as 84.8% nickel could be leached under the experimental conditions of 10% (v/v) H2SO4, 90 °C reaction temperature, le...
If calcium is present on a strong cation exchanger limited concentrations of sulphuric acid regenerant can be used to avoid CaSO4precipitation which would plug fixed bed contactors. This adversely affects water recovery and economy. At low concentrations calcium selectivity is enhanced and regeneration is...
Gypsum prodn - from sulphuric acid concentrated from waste gases and excess calcium carbonate,oxide or hydroxidePlaster of Paris or granulated gypsum, useful as raw materials for cement or mortar and slabs, are prepd. by contg. the dil. H2SO4, obtd. from the collected H2SO4 or SO2-contg...
Working-up flue-ash obtd. from exhaust gas cleaning - by forming suspension with sulphuric acid and recovering calcium sulphate as filter cakeMethod of working-up flue ash from incineration plant consists of reacting the calcium oxide/hydroxide and carbonate in the ash with H2SO4 to produce ...
the resulting acid being neutralized in a first step with calcium carbonate at a temperature of 65°C, for 2 hours, and in a second step, with calcium hydroxide at a pH value higher than 8, thereby resulting calcium sulphate having a concentration of impurities of 0.1 ppm, at the most.PR...
the resulting acid being neutralized in a first step with calcium carbonate at a temperature of 65°C, for 2 hours, and in a second step, with calcium hydroxide at a pH value higher than 8, thereby resulting calcium sulphate having a concentration of impurities of 0.1 ppm, at the most.GH...
This means that when it is dispersed in a binding agent, typically a resin of some kind, it tends to have a greater difference from the refractive index of the binder, and hence tends to look whiter and more opaque than other comparable white pigments such as calcium carbonate or zinc ...
Purifying effluent contg. sulphuric acid and iron salts - treating with calcium carbonate and recovering sulphate separatelyAn aq. sulphuric acid soln. contg Fe is treated by (a) adjusting the pH pref. to 1-4.5, by adding calcium carbonate to ppte. calcium sulphate which is sepd., (b) ...
[25 July 1975] 31187/75 Heading C1A Sulphuric acid containing dissolved iron is purified by (a) adding calcium carbonate to selectively precipitate calcium sulphate; (b) separating the precipitate from the mother liquor, (c) adding sufficient calcium carbonate to the mother liquor to give a pH...