Extraction of Alumina from Local Clays by Hydrochloric Acid Process@@@إنتاج الألومينا من الطفلة الوطنية بالمعالجة بحامض الأيدروكلوريك
A bench work study was carried out to investigate the use of kaolinitic clay containing 29.4% Al2O3 extremely abundant in Saudi Arabia for the production of pure alumina by calcination at 700 o C for 1h (recommended by previous investigators) then leached by hydrochloric acid. The effects of leaching temperature (25 o C to boiling temperature), period of activation (10-150 minutes), acid concentration (1M – 6M), particle size (–8 to –200 standard Tyler screen mesh), acid to clay weight ratio (4:1 to 15 : 1ml acid/gm clay) on alumina extraction were investigated. The recommended leaching conditions are: 6 molar for acid concentration at boiling conditions under reflux, one hour for leaching time, –100 mesh standard Tyler screens for particle size of calcined clay and 10 ml acid/gm clay for acid to clay weight ratio. Leaching this local clay sample under these conditions resulted in 32% alumina extraction. Local kaolinitic clay were calcined at temperatures varying between 400 o C and 800 o C at different calcination periods (5 to 120 minutes). The calcined clay was then leached with 3M HCl acid under the above-recommended leaching conditions. The optimum calcination conditions were 600 o C and 1 hour for calcination temperature and time period, respectively. The corresponding alumina extraction from local clay sample is about 63%.
Alumina Miniplant Operations: Separation of Aluminum Chloride Liquor from Leach Residue Solids by Classification and Thickening
Report issued by the Bureau of Mines over recovery methods of alumina through leaching of kaolin clay. The materials, equipment, and procedures used are discussed. This report includes tables, and illustrations.
The status of FAO and codex alimentarius developments on vegetable proteins
The FAO is interested in increasing world protein supplies both by advising and assisting developing countries to increase their production of staple foods and by encouraging the development of technology to produce protein concentrates both from vegetable and animal sources to supplement diets which are low in protein content. Recent revisions of the amount of protein required in the diet in relation to total per capita energy requirements and the difficulties encountered in introducing novel foods into established dietary patterns has led FAO to concentrate on increased agricultural productions in developing countries as the primary means of combatting malnutrition. In the meantime, in North America and Europe, advances in the technology of processing vegetable proteins has given highly acceptable products simulating meats which are being used as meat extenders and meat analogues. The consequent increase in vegetable protein production has revealed a need for international, agreement on standardization, and it has been agreed that this will be undertaken by the Joint FAO/WHO Food Standards’ Programme. The program operates chiefly through the Codex Alimentarius, Commission, an international governmental body, the purpose of which is to protect consumers against health hazard in food and against fraud. The Commission, which has 116 member governments, controls an intensive program of work covering the composition, labeling, additives, contaminants, pesticide residues, hygiene, sampling and analysis aspects of foods and has established a procedure which allows member governments ample opportunity to reach agreement on food standards and to accept them for incorporation into national legislation. The Codex Commission, at its 12th session, decided to establish a Committee on Vegetable Proteins with the following terms of references: “to elaborate definitions and world-wide standards for vegetable protein products deriving from soybeams, cottonseed, groundnuts, cereals and from other vegetable sources as they come into use for human consumption, and to elaborate guidelines on utilization of such vegetable protein products in the food supply system, on nutritional requirements and safety on labeling and on other aspects as may seem appropriate.” The question of which country will host the Committee is still under discussion.