PARAFFIN 511 



Paraffin is crystallised from the first distillation in several works ; but it is usually 

 ' bagged ' from the second distillation. In the crude oil, the pitchy constituents seem 

 to cling to the paraffin particles and hold them back from crystallisation, so that 

 they form an amorphous greasy mass when the light oil only is distilled off from 

 the crude. This grease, however, when distilled gives over a rich lubricating oil of 

 pale brown colour, with the paraffin crystals in such a state of free suspension 

 that they are readily separated at a low temperature. This separation of ' brown 

 paraffin scale ' is effected by ' bagging ' and pressing. The bagging is simply a 

 filtration in canvas bags, which are usually filled and tied up, then heaped together, 

 or thrown into perforated boxes till the greater portion of the oil filters out. The 

 contents of the bags are then submitted to a gradually-increasing hydraulic pres- 

 sure till the utmost possible degree of dryness is obtained in the cake of crystal- 

 line scales. 



The quantity of solid paraffin thus obtained depends in a great measure upon the 

 temperature at which these operations are conducted, as the oil is a solvent to the 

 paraffin, and the quantity it is capable of dissolving rapidly increases as the tempera- 

 ture rises. In small works this separation of paraffin is only conducted in cool 

 weather ; in larger works, refrigerating-machines are used. 



The purification of the brown paraffin scale thus obtained is now effected by 

 the simple process of dissolving it in a hot solution of the most volatile ' paraffin 

 spirit.' 



The scale having been dissolved in about an equal weight of spirit, the solu- 

 tion is set to cool in suitable vessels. As it cools, the solid paraffin recrystallises, 

 in the course of which action it rejects the impurities associated with it, giving 

 up its brown colour and the liquid solvent. The cooled mixture of crystal and 

 spirit is again submitted to pressure, whereby the spirit is separated, and the 

 crystals, now of a cream colour, are again dissolved in colourless spirit, and the 

 same treatment repeated. A third treatment is usually necessary to obtain per- 

 fect purification, when beautiful crystals of exquisite snowy whiteness are obtained, 

 presenting the most perfect contrast imaginable to the coal from which they are 

 derived. 



The chief drawback to this process is the waste of spirit by evaporation during 

 the cooling and pressing processes. By careful and intelligent management this 

 waste may be materially reduced. The refuse spirit, which has received the 

 colouring-matter and other impurities from the brown scale, is easily refined by 

 simple distillation, and may be used again and again. The brown refuse left in 

 the still may be treated afresh as crude paraffin scale, as there always remains 

 a portion of paraffin in it which continued in solution when the rest crystallised 

 out. This, however, is of inferior quality, having a lower melting-point, and is 

 usually sold in a semi-refined state for making common candles, burning in miners' 

 lamps, &c. 



In order to remove the last traces of the spirit, which if left behind, lowers the 

 fusing-point, besides giving its odour to the paraffin, the scales are fused and heated 

 to about 24:0 Fahr. ; care being taken to go no higher than this, as at 260 the 

 paraffin acquires a yellow colour similar to that of bees'-wax. It is therefore neces- 

 sary that the spirit should be freely and fully volatile at or below 240, and that all 

 the heavy oil should be separated in the earlier stages of the process. This fused 

 paraffin is run into moulds, and sold in cakes as ' paraffin wax,' which is now be- 

 coming the great staple material for the manufacture of the better class of candles. 

 Every year the price of these candles has come down lower and lower, in consequence 

 of the increased production by improved methods. 



Paraffin as washed at these various stages is now used in candle-making according 

 to the value of the manufactured material wanted. 



Whiteness, freedom from smell, and a high melting-point, are the commercial tests 

 upon which the value of paraffin depends. 



The importance of the latter may easily be understood when we consider that the 

 melting-point of the best paraffin is but 125 Fahr., while inferior qualities are much 

 lower. Paraffin, like wax, resin, and such substances, softens at many degrees 

 below its melting-point ; hence candles made of an inferior paraffin are liable to 

 bend over into strange shapes in a heated ball-room, or in a hot climate. This was 

 very vexatiously and absurdly exemplified at the coronation of the Emperor Maxi- 

 milian in Mexico, when at one of the festivals all the beautiful ' spermaceti ' candles, 

 ordered expressly from England, and numbering several thousands, though bril- 

 liantly successful at first, gradually softened as the throng increased, and finally 

 bowed over altogether, flaring hideously, and guttering in streams upon the dresses of 

 the visitors. 



Price's Candle Company, Limited, have adopted a new patented method of paraffin 



