Causticity: To 50 cubic centimeters of treated water, to which there has been added one drop of phenolphthalein dissolved in alcohol to give the water a pinkish color, add the acid solution, drop by drop, shaking after each addition, until the color entirely disappears. One-tenth cubic centimeter of acid solution corresponds to one degree of causticity.
The alkalinity may be determined from the same sample tested for causticity by the coloring with methylorange and adding the acid until the sample is on the point of turning red. The total acid added in determining both causticity and alkalinity in this case is the measure of the alkalinity.
Hardness: 100 cubic centimeters of the treated water is used for this test, one cubic centimeter of the soap solution corresponding to one degree of hardness. The soap solution is added a very little at a time and the whole violently shaken. Enough of the solution must be added to make a permanent lather or foam, that is, the soap bubbles must not disappear after the shaking is stopped.
Excess of lime as determined by nitrate of silver: If there is an excess of lime used in the treatment, a sample will become a dark brown by the addition of a small quantity of silver nitrate, otherwise a milky white solution will be formed.
Combined Heat and Chemical Treatment: Heat is used in many systems of feed treatment apparatus as an adjunct to the chemical process. Heat alone will remove temporary hardness by the precipitation of carbonates of lime and magnesia and, when used in connection with the chemical process, leaves only the permanent hardness or the sulphates of lime to be taken care of by chemical treatment.
REAGENTS REQUIRED IN LIME AND SODA PROCESS FOR TREATING 1000 U. S. GALLONS OF WATER PER GRAIN PER GALLON OF CONTAINED IMPURITIES[16]
+-----------------------+-----------+-----------+ | | Lime[17] | Soda[18] | | | Pounds | Pounds | +-----------------------+-----------+-----------+ | Calcium Carbonate | 0.098 | ... | | Calcium Sulphate | ... | 0.124 | | Calcium Chloride | ... | 0.151 | | Calcium Nitrate | ... | 0.104 | | Magnesium Carbonate | 0.234 | ... | | Magnesium Sulphate | 0.079 | 0.141 | | Magnesium Chloride | 0.103 | 0.177 | | Magnesium Nitrate | 0.067 | 0.115 | | Ferrous Carbonate | 0.169 | ... | | Ferrous Sulphate | 0.070 | 0.110 | | Ferric Sulphate | 0.074 | 0.126 | | Aluminum Sulphate | 0.087 | 0.147 | | Free Sulphuric Acid | 0.100 | 0.171 | | Sodium Carbonate | 0.093 | ... | | Free Carbon Dioxide | 0.223 | ... | | Hydrogen Sulphite | 0.288 | ... | +-----------------------+-----------+-----------+