﻿PHILIPPINE FIBERS. 99 



PULP- AND PAPER-MAKING CHEMICALS. 



The following chemicals, lime, sulphur, caustic soda, soda ash, chloride 

 of lime, kaolin, talc, gypsum, alum, etc., are largely consumed in the 

 manufacture of paper pulp, their use being dependent upon the chemical 

 process adopted for the conversion of raw fibrous material into paper 

 stock and the particular grades of the finished product it is desired to 

 make. 



Lime. — Calcium oxide (CaO), commercially known as quick or caustic 

 lime, is undoubtedly the most universally used reagent in the prepara- 

 tion of chemical pulp. Its source is the limestone deposits so widely 

 distributed throughout the world. In the alkaline process of digestion, 

 lime finds extensive use, either as such or in combination with soda 

 ash for the preparation of caustic soda, when a more active alkaline 

 reagent is required. 



In the acid or bisulphite method of treatment, lime is the base most 

 generally employed in the preparation of the sulphite liquors, here again 

 it may either be used alone to form unmixed bisulphite of calcium liquors, 

 or in conjunction with magnesia derived from the magnesian limestone, 

 called dolomite. 



A further use for lime in the paper industry is in the manufacture 

 of bleaching powder (chloride of lime) and it may be employed in the 

 form of the sulphate, as pearl hardening or as gypsum to furnish a 

 mineral loading material in certain grades of paper. 



Sulphur. — The principal sources of the world's supply of sulphur 

 are found in Sicily, in Louisiana and Utah in the United States, and in 

 Japan. In the form in which it is brought on the market it is classified 

 according to its degree of fineness. A second or third grade, containing 

 one-half to one per cent of foreign matter and ash, is usually employed in 

 the preparation of sulphite liquors. Sulphur comes to the mills in 

 sacks or barrels and it is burned as needed, the sulphurous acid gas which 

 is formed either being passed into water containing the lime in solution 

 or suspension, or through a long vertical column of coarse limestone or 

 dolomite, sprinkled with water. 



Caustic soda and soda ash. — Caustic soda (NaOH) and soda ash 

 (Na 2 C0 3 ) appear on the market in different states of purity, their value 

 depending on the amount of alkali (Na 2 0) present. The grades which 

 find most general use among paper makers are 78 per cent caustic soda 

 and 48 per cent ash. 



The present market quotations are as follows : 15 



Caustic soda (78 per cent), per ewt $1.75-1.85 



Soda ash (48 per cent), per cwt 75- .80 



15 The duty on these chemicals on entering the port of Manila is 25 cents per 

 100 kilos (220 pounds) gross weight. (Philippine Customs Tariff, Par. 93.) 



