(3) The large quantities of chalk residue resulting from the reaction must be thoroughly and carefully washed. The economy of the whole process depends in no small measure upon this seemingly small detail.
Caustic Soda Tables.
Showing quantity of liquor obtained from 1 cwt. of caustic soda and the amount of caustic soda in 100 gallons of liquor (adapted from Lunge and others).
| Twaddell. | Gallons obtained per hundredweight of Caustic. | Twaddell. | Pounds of Caustic Soda per 100 gallons Liquor. | |||
| 60 per cent. Caustic. | 77 per cent. Caustic Pure. | 60 per cent. Caustic. | 77 per cent. Caustic Pure. | |||
| 1 | 1,777 | 2,358 | 1 | 6·3 | 4·75 | |
| 2 | 896 | 1,179 | 2 | 12·5 | 9·5 | |
| 3 | 596 | 767 | 3 | 18·8 | 14·6 | |
| 4 | 448 | 574 | 4 | 25·0 | 19·5 | |
| 5 | 359 | 457 | 5 | 31·2 | 24·5 | |
| 6 | 298 | 384 | 6 | 37·6 | 29·2 | |
| 7 | 256 | 330 | 7 | 43·8 | 34·0 | |
| 8 | 223 | 287 | 8 | 50·1 | 39·0 | |
| 9 | 199 | 256 | 9 | 56·2 | 43·7 | |
| 10 | 178 | 229 | 10 | 62·9 | 48·9 | |
| 11 | 162 | 208 | 11 | 69·1 | 53·7 | |
| 12 | 148 | 190 | 12 | 75·7 | 58·7 | |
| 13 | 136 | 176 | 13 | 82·1 | 63·7 | |
| 14 | 126 | 166 | 14 | 88·5 | 67·5 | |
| 15 | 117·5 | 152 | 15 | 95·0 | 73·5 | |
| 16 | 110 | 141·5 | 16 | 101·5 | 79·0 | |
| 17 | 103·5 | 135 | 17 | 107·8 | 83·0 | |
| 18 | 98 | 125·5 | 18 | 114·4 | 89·0 | |
| 19 | 92·8 | 119·5 | 19 | 120·8 | 93·8 | |
| 20 | 88 | 114 | 20 | 127·2 | 98·0 | |
| 25 | 70 | 90·3 | 25 | 159·5 | 124·0 | |
| 30 | 56·5 | 73 | 30 | 197·3 | 153·0 | |
| 35 | 48 | 61·5 | 35 | 234·9 | 182·2 | |
| 40 | 41 | 53 | 40 | 272·6 | 211·6 | |
| 45 | 35·3 | 45·5 | 45 | 317·4 | 246·3 | |
| 50 | 31 | 40 | 50 | 362·1 | 281·0 | |
Dilution Table for Strong Liquors.
Showing number of gallons of water required to reduce the density of 100 gallons of liquor from a higher density, D, to a lower density, d. (See page [163]).
| Higher Density, D (Twaddell). | Lower Density, d. | ||||||||||
| 14. | 13. | 12. | 11. | 10. | 9. | 8. | 7. | 6. | 5. | 4. | |
| 42 | 200 | 223 | 250 | 281·8 | 320 | 367 | 425 | 500 | 600 | 740 | 950 |
| 40 | 185 | 207 | 233·3 | 263·6 | 300 | 344·4 | 400 | 471·4 | 566·6 | 700 | 900 |
| 38 | 171 | 192 | 216·6 | 245·5 | 280 | 322·2 | 375 | 442·8 | 533·3 | 660 | 850 |
| 36 | 157 | 177 | 200 | 227·3 | 260 | 300 | 350 | 414·3 | 500 | 620 | 800 |
| 34 | 143 | 161·5 | 183·3 | 209·1 | 240 | 277·7 | 325 | 385·7 | 466·6 | 580 | 750 |
| 32 | 128·6 | 146 | 166·6 | 191 | 220 | 255·5 | 300 | 357·1 | 433·3 | 540 | 700 |
| 30 | 114·3 | 130·6 | 150 | 172·8 | 200 | 233·3 | 275 | 328·5 | 400 | 500 | 650 |
| 28 | 100 | 115·3 | 133·3 | 154·6 | 180 | 211·1 | 250 | 300 | 366·6 | 460 | 600 |
| 26 | 85·7 | 100 | 116·6 | 136·4 | 160 | 188·8 | 225 | 271·4 | 333·3 | 420 | 550 |
| 24 | 71·4 | 84·6 | 100 | 118·2 | 140 | 166·6 | 200 | 243 | 300 | 380 | 500 |
| 22 | 57·1 | 69·2 | 83·3 | 100 | 120 | 144·4 | 175 | 214·4 | 266·6 | 340 | 450 |
| 20 | 43 | 53·6 | 66·6 | 81·8 | 100 | 122·2 | 150 | 185·7 | 233·3 | 300 | 400 |
| 18 | 28·6 | 38·4 | 50 | 63·7 | 80 | 100 | 125 | 157 | 200 | 260 | 350 |
| 16 | 14·3 | 23 | 33·3 | 45·5 | 60 | 77·7 | 100 | 128·5 | 166·6 | 220 | 300 |
Lime and Limestone.—Carbonate of soda and recovered ash are converted into caustic soda by means of lime. About sixty parts of lime are necessary for the conversion of 100 parts of carbonate of soda. Large quantities of insoluble carbonate of lime are produced in this operation, and great care is necessary to prevent a loss of caustic soda which occurs if the residue is not thoroughly washed. In some cases the residual chalk is drained by vacuum filters in order to remove all traces of soluble alkali. Processes have been devised for calcining the residue so as to convert the carbonate into caustic lime to be used over again, but no economical and practical method has yet been found. The treatment of the residual chalk with sulphuric acid for the production of calcium sulphate appears feasible, but the substance obtained is very impure, and therefore has little commercial value.