Reprocessing of the Rice Hulls
Development of Technology for Complex Processing of Annually Renewable Vegetative Raw Material (Rice Hulls) with the Object of Producing Silicocarbon and Organic Product Used in Various Areas of Technology, Agriculture and Medicine
Tech Area / Field
- MAN-MAT/Engineering Materials/Manufacturing Technology
8 Project completed
Senior Project Manager
Yakusheva A A
The National Center for Mineral Raw Materials Complex Processing, Kazakstan, Almaty
- The S. M. Kirov Machine Building Plant OJSC, The Science and Technology Center “Lama”, Kazakstan, Almaty
- Center for Advanced Mineral & Metallurgical Processing, USA, MT, Butte
Project summaryThe object of this Project is to develop and test the technology, equipment and build up a pilot production for producing from the rice hulls (RH) the multifunctional materials: silicocarbon (SC) and organic product OP), to lay down the basis for setting up their industrial production, and to solve certain ecological and social problems.
Every year about 50 thousand tons of the RH are produced at the rice processing plants in Kazakhstan. These rice hulls are, primarily, removed to the dumps where gaseous toxic substances are emitted because of the RH decomposition in the ambient air generating great ecological problems in these regions. The same problems exist in a number of other countries (the USA, Russia, China, India, etc.) but there are no adequate technologies implemented in the industry.
At the same time, as the results of the laboratory research demonstrated, after appropriate RH processing it is possible to receive valuable products: silicocarbon and organic product. The SC represents the homogeneous mixture of amorphous highly active carbon (~50% by weight) and silica (~45% by weight), and it may be applied as a fodder admixture, sorbent, filling agent for industrial rubber articles and carbonic products, and also as the primary raw material for producing polycrystalline silicon and other silicon containing compounds. The OP represents a condensed mixture of phenols, organic acids, spirits and neutral fraction. This OP has a well-defined antimicrobial activity, and it may be used as bactericidal preparation in agriculture and medicine, as well as the primary raw material for producing organic acids, tanning agents, synthetic rubber polymerization inhibitor and petrol antioxidant, etc.
The SC application in the tire rubber instead of technical carbon (TC P-514) and silica white (SW-120) shall improve physical and mechanical indicators: conventional stress and adhesiveness of the rubber (tread-, valve- and cushion rubber, etc.). In particular, the rupture strength in the rubber for the rim bands shall increase from 80 kgf/cm2 (reference standard) to 90 kgf/cm2.
When manufacturing the rubber agricultural boards, the SC application instead of technical carbon shall increase by 10-15% the conventional rupture strength, conventional stress, relative elongation at rupture, and ultimate breaking strength while the dynamic fatigue strength is increased by 2-4 times.
Owing to the introduction of 10-20% of the SC into the standard charge to produce carbonic antifriction products – the end seals with the friction pair made of the material of the Nigran-B type by the steel and alloy GAKK55/40 – the gas permeability became almost by one order lower, and these products’ service life in the corrosive became greater. These indicators are especially significant for equipment used in the ore-mining and coal-mining industries.
At present, the revealed demand of some Kazakhstan’s enterprises in the SC for technical rubber and special carbonic products amounts to 3 thousand tons/year, and in the future it will increase up to 7 thousand tons/year.
Application of the SC as a fodder admixture into the ration of the farming poultry will increase by 38% the liveweight gain of the chickens, decrease by 28% the fodder consumption per unit of their gain and increase by 7.5% the egg-laying intensity of the hens.
The processing of the feed for the ducklings with the organic product (8 ml per 1 kg of the feed) decreases the feed consumption by 5.5%, and at the same time the liveweight gain increases by 12%.
The demand in the SC as a fodder admixture into the ration of the farming poultry will amount to 3,600 tons/year for the poultry breeding plants of Kazakhstan. The economic effect due to the use of the SC will amount to $1,400 per 1 ton of the SC.
The commercial-scale plant will have productivity of 1,000 tons of the SC and 600 tons of the OP per year. The price cost of the SC (without considering the OP) will amount to $180-200 per 1 ton. At the selling price of $300-350 per 1 ton of the SC (i.e. lower than the price for technical carbon – the SC analogue) this production facility will be profitable.
Thus, the fundamentally new decision in the proposed by us Project shall be the equipment and technological design of the process for the rice hulls pyrolysis and some non-traditional fields of the produced products application.
This Project provides for:
a) Study of the RH pyrolysis process, physical and chemical properties of the produced SC and OP with the aim to work out recommendations related to the parameters of the pilot plant and to choose the trend of the researches on investigating the most optimal areas of these products use.
b) The designing and technological studies on establishment of a pilot plant for producing the SC and OP with the output of 5-6 kg and 2-3 kg per hour respectively; this plant’s construction and mounting at the pilot site; finishing the technology off under the optimal conditions and producing the pilot batch of the products.
c) The production tests on the SC and OP direct application in the most optimal areas of the industry and agriculture and determining of certain ways for the SC processing in order to produce perse silicon-containing materials.
d) Technical and economic assessment of the SC and OP production and application, pre-project study of the issue for setting up the industrial-scale production of the SC and OP.
Implementation of the Project will make it possible to create the basis for industrial production of new advanced materials from the anthropogenic raw material and to solve important ecological and social problems including creation of new jobs in the labor-excessive regions.