Broadly speaking, there are two methods for processing waste paper, namely, continuous and batch systems. The batch process is recommended for this plant for the daily production capacity of the mill is very small.
The manufacturing process begins when waste paper is moved up to the sorting yard above the digester by elevator. The sorted waste paper is fed into the global digester. Simultaneously with the feeding, sodium sulphite, soda ash, etc. are sprinkled thoroughly over the waste paper. After stuffing of the digester has been completed, the gut for the digester is tightly closed. Steam is blown into the digester as it is rotated.
The next step is the charging of the material into the blow poacher. Circulation is performed
by a propeller agitator, and the digesting chemicals are thoroughly washed in the washing drum. When the washing is over, the material is transferred into the dump chest, from where it is moved up into the head box by pump. Water is added for dilution in the head box. The material is then sent through the sliver screen and the Johnson screen for removal of dust. The material which comes out of the screen is transferred into the extractor for washing and dickering.
by a propeller agitator, and the digesting chemicals are thoroughly washed in the washing drum. When the washing is over, the material is transferred into the dump chest, from where it is moved up into the head box by pump. Water is added for dilution in the head box. The material is then sent through the sliver screen and the Johnson screen for removal of dust. The material which comes out of the screen is transferred into the extractor for washing and dickering.
The material coming out of the extractor is stored in the bleaching chest. When a chest becomes full, bleach liquor is added. After the material has been left in the bleaching chest for a fixed time following the bleaching, it is flow-fed into the mixing chest, in which bleach liquor is thoroughly washed away. Washing takes place in the washing drum.
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After the washing, fluorescent dyestuff or rhodamine is applied for coloring as may be required by consumers. Now that this process has been completed, it is dropped into the stock chest, and sent into the machine chest. Out of the machine chest, the stock is fed into the head box for flow-fed into the mixing tank at a regulated feed level.
In the mixing tank, the stock is diluted with white water coming out of the wire part, of which more hereafter, and then sent onto the vertical screen. On the vertical screen, stock with a comparatively larger specific gravity and non-digested stuff are removed.
The material which has passed through the vertical screen goes into the tank and, via the high-pressure pump, is fed into the cleaner, with only accepted material fed into the paper making machine.
The accepted material goes into the flow box of the paper machine, out of which a fixed amount flows out into the wire part in consistency of about 0.15-O-2 per cent. The stock which flows out is dehydrated by the table roll and suction box for transformation into a wet web, which is sent into the press part over a blanket. The wet web is dewatered under the pressure of the roll, and pushed against the Yankee dryer.
The wet web is dried by the heat of steam inside the Yankee dryer. At the outlet of the dryer, the web is creped by a special crepe doctor, after which it is wound into rolls.
The base paper of the toilet paper, which has been reeled, is cut into the fixed width by the slitter on the toilet machine and wound into rolls in the required length. If the producer requires alternative technology he can employ Semi-Boiled or Cold processes which are economical and simple ways of making soft or potash soaps, requiring low-cost investment in equipment and no sophisticated skills. The use of both processes, however, is markedly decreasing due to the poor quality of the soap produced and the impossibility of glycerin recovery. This is especially true of the production of toilet soaps where quality is always a critical factor. In addition to the above two alternatives, continuous processes with automated and compact equipment are widely employed to save installation space, consumption of steam and electric power and labor.
