Patent GB-498201-A (GB)
Title: A process for the manufacture and revivification of active carbonaceous material
IPC: C01B31/08
Filed: 1937-10-18
Abstract: An active carbonaceous colloid is made or revivified by adding to oxygen-containing carbonizable material, e.g. wood, wood refuse, peat, lignite, bagasse, molasses, straw, mineral coal, grain and seed husks &c., sulphuric acid, oleum, phosphoric acid or their strong aqueous solutions which have been preheated, and in an amount not exceeding twice the weight of the carbonizable material.  Usually, a spontaneous exothermic reaction ensues which should preferably not exceed 15 minutes, and the temperature should preferably not exceed 350 DEG  C.  The nature of the products is influenced by the water-content of the components and the extent to which the acids are preheated.  A diluted acid should be preheated to a greater extent, in any case preferably over 40 DEG  C., and the higher the temperature to which the acid is preheated the more nearly the product approaches active carbon.  During the reaction, carbonization and hydration occur, and when sulphuric acid is used, sulphonation to a very slight degree also occurs. To assist moistening, the acid may be diluted, e.g. with extracts from the material manufactured or with solutions of inorganic salts, and these diluents may be added before or during the mixing with the carbonizable bodies.  It is advantageous if heat is developed thereby.  The reaction is preferably carried out in a substantially closed mixing vat, in which an initial increase of pressure is allowed to develop, to assist mixing.  The reaction vessel may be heated to compensate for heat losses, to assist evaporation of water or to support or initiate the reaction, but this heating should not be used to increase the reaction temperature.  The carbonizable material is preferably pre-dried, either partially or completely, and may also be partially carbonized or pre-treated with dehydrating chemicals, in several stages if desired.  Mineral coal or used active carbonaceous material requires strong heating and/or dehydration of the components. Storage of the reaction product before washing improves its properties.  The products possess ion-exchange properties and also act as adsorbents or as decolourizing agents or to absorb gummy or froth-forming substances.  According to examples: (1) 40 kgs. of sawdust were mixed with 25 litres of 60 DEG  B<\>ae. sulphuric acid, preheated to 70 DEG  C. in an autoclave with a stirrer and a 1 1/2 inch free outlet.  When all the acid was added and mixed for 3 minutes, an explosion occurred with an increase of pressure to 1 1/2 atmospheres; (2) 30 kgs. of sawdust were dried in a similar autoclave at 150 DEG  C. after which 30 litres of 66 DEG  B<\>ae. sulphuric acid heated to 150 DEG  C. were added.  A violent reaction occurred, and after 15 minutes, the mass was removed, left in contact with water and then leached. These products may be used for the general decolourizing and purifying of thick sugar juice, but the product of example 1 is not suitable for decolourizing remelted sugars; (3) 40 kgs. of sawdust were treated with 25 litres of 60 DEG  B<\>ae. sulphuric acid heated to 150 DEG  C., as described in the first example; (4) 40 kgs. of pine-wood shavings were mixed with 70 litres of 60 DEG  B<\>ae. sulphuric acid at ordinary temperatures, stored for 24 hours in a closed vat and the excess acid then removed.  The black mass was then treated according to the second example; (5) 66 DEG  B<\>ae. sulphuric acid was heated in a closed vat until a pressure of 2 atmospheres was developed.  30 litres were then sprayed into a closed autoclave containing 30 kgs. of sawdust.  Specification 306,490, [Class 90], is referred to.ALSO:An active carbonaceous colloid is made or revivified by adding to oxygen-containing carbonizable material, e.g. wood, wood-refuse, peat, lignite, bagasse, molasses, straw, mineral coal, grain and seed husks, &c., sulphuric acid, oleum, phosphoric acid or their strong aqueous solutions which have been preheated, and in an amount not exceeding twice the weight of the carbonizable material.  Usually, a spontaneous exothermic reaction ensues which should preferably not exceed 15 minutes, and the temperature should preferably not exceed 350 DEG  C.  The nature of the products is influenced by the water content of the compounds, and the extent to which the acids are preheated.  A dilute acid should be preheated to a greater extent, in any case preferably over 40 DEG  C., and the higher the temperature to which the acid is preheated, the more nearly the product approaches active carbon.  During the reaction, carbonization and hydration occur, and when sulphuric acid is used, sulphonation to a very slight extent also occurs.  To assist moistening, the acid may be diluted, e.g. with extracts from the material made or with inorganic salt solutions, and these diluents may be added before or during the mixing with the carbonizable bodies.  It is advantageous if heat is developed thereby.  The reaction is preferably carried out in a substantially closed mixing vat, in which an initial increase of pressure is allowed to develop, to assist mixing.  The reaction vessel may be heated to compensate for heat losses, to assist the evaporation of water or to support or initiate the reaction, but this heating should not be used to increase the reaction temperature.  The carbonizable material is preferably pre-dried, either partially or completely, and may also be partially carbonized or pre-treated with dehydrating chemicals, in several stages if desired.  Mineral coal or used active carbonaceous material requires strong heating and/or dehydration of the components.  Storage of the reaction product before washing improves its properties.  The products possess ion-exchanging properties and also act as adsorbents or as decolourizing agents or to absorb gummy or froth-forming substances. According to examples: (1) 40 kgs. of sawdust were mixed with 25 litres of 60 DEG  B<\>ae. sulphuric acid, preheated to 70 DEG  C., in an autoclave with a stirrer and a 1 1/2 inch free outlet.  When all the acid was added and mixed for 3 minutes, an explosion occurred with increase of pressure to 1 1/2 atmospheres; (2) 30 kgs. sawdust were dried in a similar autoclave at 150 DEG  C., after which 30 litres of 66 DEG  B<\>ae. sulphuric acid heated to 150 DEG  C. were added.  A violent reaction occurred and after 15 minutes the mas was removed, left in contact with water and then leached.  These products may be used for the general decolourizing and purifying of thick sugar juice, but the product of example (1) is not suitable for decolourizing remelted sugars; (3) 40 kgs. sawdust were treated with 25 litres of 60 DEG  B<\>ae. sulphuric acid heated to 150 DEG  C., as described in the first example; (4) 40 kgs. of pine-wood shavings were mixed with 70 litres of 60 DEG  B<\>ae. sulphuric acid at ordinary temperatures, stored for 24 hours in a closed vat and the excess acid then removed.  The black mass was then treated according to the second example; (5) 66 DEG  B<\>ae. sulphuric acid was heated in a closed vat until a pressure of 2 atmospheres was developed.  30 litres were then sprayed into a closed autoclave containing 30 kgs. of sawdust.  Specification 306,490, [Class 90], is referred to.