Document jBdQ9B4EqK8wq1OJ9dedqqnZp

FILE NAME: Longview Fibre (LF) DATE: OOOO DOC#: LF011 DOCUMENT DESCRIPTION: Company Specifications for Adding Asbestos to Paper Manufacturing Am IA U ^ ajmmJ4 Irfflihk PREPARATION AMD METHOD OF ADDITION OF THE H IG H -PU R m ASBESTOS FIBER TO THE FURNISH FOR THE MiUWACTUKE OF PAPER 1- Method of Addition The asbestos fib er i s added to the stock preparation system for homogeneous d istribution in the same manner as regular wood pulps. Present ex perience and information on retention properties suggests the following order of addition when using a slurry or opened asbestos fib e r: * a. White water .1 /\ b. Asbestos c Normal order of addition for pulps t d. Resin i e. Filler 4 4 t. Rye 6* Alum Suggested practice above i s based on the normal makeup. Unusual deviations from the system makeup shown above should be considered as a special case. For example, i f bentonite or ta lc were being used, normally the elimina tion of th is m aterial would be suggested. Asbestos fib er with i t s superior o il absorbency ch aracteristics, as well as i t s high sp ecific surface value would be more effective for pitch control properties. For furnishing Kraft or su lfite specialty grades furnish makeup .should be planned for m ill t r ia ls considering the individual characteristics for each system. As with a l l stock preparation systems for proper blending of pulps, good agitatio n to obtain a uniform distribution of the blend of pulp and asbestos fib er is desirable. Fran experience and the technology developed to date the fibrous asbestos should be treated as a pulp rather than an additive. UCASB00749194 2 - 2. Points of .Addition A. Batch Type Furnish Makeup Systems The high-purlty asbestos fib er can be blended with the furnish in: 1. Hydropulpers 2 . Slu sh m sk ers 3* Beaters (vhen r o ll is used for blending or beating) k. Dynopulpers 5. Hi-Lo pulper 6. Fulpmaster 4 4d l. Mix tanks with good agitation B . Continuous Stock Systems When pulps and chemicals are continuously blended for furnish and chemical makeup, asbestos fiber can be dispersed at 2$ solidB in m Union Carbide's new p e lle t disintegrator. Good mechanical shear-type agitation i s desirable but not absolutely esse n tia l. Experience re veals that a mixing tank with a centrifugal pump and recirculation lin e w ill provide adequate agitation for opened high-purity asbestos i fiber. 4 4 4 C. Specific Retention. Applications - Eye Retention Improvement 4 44 With c r it ic a l dye retention problems where the asbestos is to be evaluated s tr ic tly for dye efficiency improvement in the manu facture of specialty products, premixing of the asbestos and dye solu tion should be practiced. With' a batch system, th is is done as the . f i r s t step in furnish makeup. With a continuous system a mix tank would have to be used. That i s the continuously metered dye solu tions and the continuously metered asbestos fibrous slurry would be fed to a small mixing tank which could be gravity-fed to the furnish blending chest. With a l l applications for paper quality improvements and ma t e r ia l retention improvements, methods of incorporating the asbestos fib e r should be used to allow homogeneous distribution and intimate contact. Union Carbide's new p ellet disintegrator can be used i f there is any doubt. D. pH Conditions For best dispersion asbestos fiber should be blended with the furnish in the pH range of b to 6 -- 5 i s optimum. UCASB00749195