Ferrous aluminium sulphate

For the treatment of camotite several methods are available. The method recommended by the United States Bureau of Mines2 is as follows The ore is leached with concentrated nitric acid at 100° C., neutralised with caustic soda, and barium chloride and sulphuric acid added to the solution to precipitate the radium as barium-radium sulphate. The precipitate settles in three or four days, after which time the clear liquid is decanted into tanks and is treated with excess of boiling sodium carbonate solution in order to precipitate any iron, aluminium and chromium present. The solution now contains sodium uranyl carbonate and sodium vanadate. It is nearly neutralised with nitric acid, and caustic soda is added in sufficient quantity to precipitate the uranium as sodium uranate. After filtering, the remaining solution is neutralised with nitric acid and ferrous sulphate added, whereupon iron vanadate is thrown down. By this method it is claimed that 90 per cent, of the radium, all the uranium, and 50 per cent, of the vanadium in the camotite are recovered. 

A tube of difficultly fusible glass, sealed at one end, is filled with a mixture of 3 parts of dry sea-sand and 2 parts of ammonium nitrate dried at 105°, which is kept in position by an asbestos plug the end of the tube is closed by a cork through which passes a delivery tube with a tap. A small aluminium box, fitted with a thermometer and serving as an air-bath, is arranged to slide along the tube. The best temp, to employ is 260<,-285°, and the back end of the tube is first heated when all the air has been expelled from the tube, the gas is passed, first through aqueous ferrous sulphate or alkaline sodium sulphide soln., VOL. VIII. 2 c... 

The nascent hvdrogen reduces anv nitrates or nitrites to ammonia. Atmospheric oxygen converts the ferrous salt into colloidal feme hydroxide, a reaction that is facilitated by cascade aeration. As it coagulates and settles, the ferric hydroxide punfies the water in an analogous manner to that described for aluminium hydroxide above. The process is rather expensive, however, and for this reason some American towns have added ferrous sulphate direct to their waters. This is less satisfactory as the salt is not oxidised so readily as ferrous bicarbonate m addition to this, sulphuric acid is introduced into the water. 

Ferrous aluminium sulphate, FeS04.Al2(S04)3.24H20, occurs in nature as halotrichite (see p. 25), and may be prepared in the laboratory by concentration of a solution containing ferrous and aluminium sulphates in equimolecular proportions. At first ferrous sulphate crystallises out, but this is followed by the double salt.3... 

Ferric sulphate is slowly soluble in water, and dissolves more readily in the presence of ferrous sulphate,4 but its solubility is lowered by addition of aluminium sulphate.5... 

Materials Tin, aluminium, iron nail, concentrated nitric acid, solutions of stannous chloride, stannic chloride, ferric chloride, ferrous sulphate, ammonium sulphide. 

Materials Aluminium zinc tin solutions of zinc sulphate, ferrous sulphate, and ammonium sulphide. 

Coagulants are often added in conjunction with lime to increase the settling rate of calcium carbonate and magnesium hydroxide. Most of these coagulants are acidic in nature and react with the alkalinity of the water. Commonly used coagulants include aluminium sulphate (alum), sodium aluminate, ferric sulphate and ferrous sulphate (Table 6.8). Alum reacts with natural alkalinity in water to form aluminium hydroxide floe (Equations 2.5—2.8) [14]. About 1 ppmofalumdecreaseswater alkahnity by 0.5 ppm and produces 0.44 ppm of CO2 ... 

Iron (n) sulphate FeS04-7H20 in saturated solution has only a slight action in aluminium at room temperature, and it is, therefore, possible to transport and to store ferrous sulphate solutions in aluminium vessels. However, as soon as ferrous sulphate oxidises to ferric sulphate, the medium becomes very aggressive towards aluminium. 

Sodium chloride Sodium bromide Sodium iodide Sodium sulphate Sodium silicate Potassium sulphate Lithium chloride Calcium carbonate Calcium sulphate Magnesium sulphate Manganous carbonate Ferrous carbonate. Aluminium phosphate Ammonium nitrate Organic matter... 

Conversion into the sulphate is effected by weathering, a slow and expensive process by calcination, for ores containing a high percentage of iron pyrites by calcination with ferrous or aluminium sulphate or by calcination with ferric sulphate as an adjunct to the weathering process. 

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