Title: The Production of Hard Compact Carbonaceous Material Through Acid/Alkali Treatment.
Suaβary of the Invention
In essence , the invention described herein involves the treatment of carbonaceous material with water or aqueous acid or aqueous alkali or a combination of these so as to produce a carbonaceous material of altered composition and in general exhibiting improved hardness and abrasion resistance. The treatment may be adjusted so as to produce a carbonaceous material contaning elements, principally metals, in intimate contact with the carboneous material as may be advantages in subsequent process.
Alternately the inorganic and mineral contents may be altered or reduced to obviate problems associated with their presence in subsequent processes. The products of this process described herein, may be produced as powdered or granular forms or they may be formed into shapes for future beneficial use.
Carbonaceous materials suffer in commercial applicaion through a lack of resistance to abrasion and through levels of inorganic or mineral constituents which are inappropriate in the final application of the carbonaceous material.
In the invention described herein carbonaceous material, including wood based material, coal, lignite, peat and like carbonaceous material, is ground to a fine state, either with or without previous drying procedures, added to water and aqueous alkali to form a paste, exhibiting gel like properties under appropriate conditions, and extruded to form pellets or applied as a slurry to a tray or pan or similar drying area and allowed to dry or is subjected to forced drying. The dried or partially dried carbonaceous material which has been so treated is then leached using water at a tempreature between 0 deg C and 1000 deg C or with dilute aqueous acid between such temperatures. The leached material is then dried to form a hard compact product.
A proportion of the carbonaceous material is removed by this process together with a proportion of the mineral and inorganic material. The carbonaceous products so formed by this process, or by similar process in which the material is subjected to acid and alkali treatment in different order or in which the products are dried or partially dried between the processing steps, have an altered mineral and inorganic content and good resistance to abrasion on drying. Such alteration to the inorganic and mineral content may be beneficial in processes such as combustion,
gasification, carbonization, ion exchange processes and n 1iquefaction processesi
For example, liqnite or brown coal, treated by this process using potassium hydroxide as the alkali and leached using water alone, gave a hard * compact carbonaceous product from the insoluble fraction » loaded with potassium in intimate contact with the carbonaceous components of the product, rendering it suitable for processes such as gasification, where the potassium acts as a catalyst or in adsorption processes or ion exchange processes in which the potassium ions may be replaced by other ions. The hardness or abrasion resistance of this product is significantly better than briquettes or solar densified coal produced from the same coal feed. Alkali within the meaning of the above process is specifically to include carbonates.