An invention for this purpose ha3 been lately patented in England ; as it is of some importance we give the full particulars : The plants or fibres to be acted upon are placed in large cisterns, boiling caustic and other lyeswhich may have been previously usedare added ; and should they not be sufficiently strong, the inventor introduces hot water saturated with quick lime, and thus obtains caustic retting. These cisterns may be kept heated by a jet of steam. Three, four, or five days, according to the plant or fibrous substance operated upon, will generally be found sufficient to bring it to a good state of retting, and for being passed through a breaking or decorticating machine, in order to open up the fibers and separate foreign matters from them. The plants or fibers are fed on to an endless belt, which delivers them on to a shoot, from whence they fall between a hollow semicircular stationary plate, smooth, toothed, or fluted, and a rotating drum with a fluted or roughened surface. After getting out of the action of the drum, the fibers are received into f a trough at the bottom of the machine, and are washed in clear water. The fibers being fa now deprived of the greater part of the gum M and resin, and other foreign matters adhering to them, and having also received a commencement of disintegration and denning, the lye which is aout to be explained is intended to remove the remainder of these substances, and to prepare the complete separation of the filaments from each other, and to commence the decoloration of these filaments which the washing, after coming from the barking machine, only prepared. For the next operation a rotating closed boiler is preferred, but a closed wooden or metal vessel may be used. The vessel is charged with the barked and washed filaments. A sufficient quantity' of water is introduced, so that when boiling, the matters shall be covered by it ; or if a rotating boiler is used, less water will be needed than for a stationary. For every 200 pounds of filamentous matters, add in the boiler or vessel 2 lbs. of subcarbonate of soda crystallized, and eight or ten quarts of liquid chloride of lime at 2 to every 100 quarts of pure water. When the fibers have been exposed to the action of these agents for a time, varying with the nature of the material under treatment, they are removed to a double acting washing, opening, and separating machine. This machine is fed with clear cold water. It is divided lengthwise through the center, and at opposite ends, and on opposite sides, there are two inclined fluted metal surfaces, the faces of which are armed with blades ; and working towards or against these blades are other blades projecting from a cylinder or drum, to which rotary motion is communicated. In the machine there are also placed two revolving drums, to which rotary motion is also communicated. The fibrous substances are continuously subjected to the action of the armed cylinders and plates, and to the action of the washing drums. When sufficiently washed (which experience will readily dictate) the quantity of water is diminished in the machine, and the bleaching is commenced by introducing some of the bleaching agents set forth in a specification filed by the applicant, December, 1856. After a certain time, these bleaching agents are drawn off, cold water is introduced, and the fibers are subjected to another washing. When washed they are removed to or into another vessel, where they receive their final bleaching. In this vessel agitation is kept up by means of a paddle wheel, to whicli slow rotary motion is communicated. After the bleaching has been effected, the bleaching agents are drawn off, clear water introduced, and washing drums extending across the machine are set in motion to finally wash the fibrous matters.
This article was originally published with the title "Bleaching Fibrous Materials"