Rice Husks Before And After Steam Explosion (SE)   SE, extracted husks* Rice husks SE husks water water/dioxan Extractives Ether soluble 0.4% Ethanol soluble 5.0% Extractives Total 5.4% Polysaccharides Rha 0.1% Ara 1.7% 0.2% Xyl 14.4% 2.8% 2.3% Man 0.3% Glc 33.4% 32.9% 49.2% Gal 1.6% 0.8% 1.2% Polysaccarides Total 51.5% 37.0% 52.8% Lignin (AcBr) 25.5% 45.8% 20.0% Klason Residual 23.5% 30.4% 33.8% Ash 15.5% 17.7% 18.6% 24.9% Total 98.0% 100.5% 97.7% Rha: rhamnose; Ara: arabinose; Xyl: xylose; Man: mannose; Glc: glucose; Gal: galactose (as anhydro sugars) Lignin (AcBr: lignin determined by acetyl bromide method * - Extracted with water and dioxan (90%)

The Basic Components Of Rice Husks Ash wt (%) mg/kg Error ± (%) SiO2 90.50 905000 0.5 Al2O3 0.59 5900 0.1-0.2 Fe2O3 0.51 5100 0.1 CaO 0.65 6500 MgO 0.48 4800 Na2O 0.41 4100 K2O 3.83 38300 0.15 Loss of mass   1000ºC 1.70 Total 98.67

Concentration Of Minor Metallic Components In Rice Husks Ash (mg/kg) Element Content (mg/kg) Sdev · t (95%) Cd 0.347   Cr <0.7 Cu 2.08 Zn 15.1 ± 1.0 Pb <2.3 Ni <1.3 Co

High Tech Materials From Rice Husk Si (?) nano-ceramics alaoxy silicons exceptionally selective and voracious nano-sorbents carbon ceramics

CO → CO2 OXIDES RICE HUSKS (SiO2) T Si O2 SiO2 + 2C → Si + 2CO

LOW TEMPERATURE PLASMA RICE HUSKS PRODUCTS: nano-powders (20-100 nm) β – SiC α -, β – Si3N4, X-ray amorphous nano-ceramics PLASMATRON

FT IR Spectra of Rice Husks

Characteristics of produced products Precursors SSA, m2/g N, wt.% C/Si XRD Rice husk 42 3.9 0.56 -SiC Rice husk+SiO2 21.8 3.1 0.37 Rice husk+Si 20.7 4.5 0.38

Experimental The nanosize nitride or oxide based composites are prepared by evaporation of coarse commercially available powders of chemical elements and their compounds and subsequent condensation of products into a radio frequency inductively coupled nitrogen or oxygen plasma (ICP). The elaborated experimental apparatus (Fig. 1) consists of radio-frequency (5.28 MHz) oscillator with maximum power of 100 kW, quartz discharge tube with induction coil, raw powder and gas supply systems, water cooled stainless steel reactor and heat exchanger, and cloth filter for collecting powders. Optimal parameters of the radio-frequency oscillator and parameters of the plasma are determined by calorimetric methods. The growth of product particles and their phase and chemical composition are regulated by changing the velocity of the plasma flow and introducing cold gas (ammonia, hydrocarbon, hydrogen, air) into vapours. The process is optimised by studying the dependence of the particle size, their phase and chemical composition, and the production rate on the flow rate of plasma and cooling gases, the feeding rate of precursor powders, parameters of the plasma flow. The chemical and phase composition of prepared powders is determined by conventional chemical and X-ray powder diffraction analysis. The specific surface area of powders is determined by the BET argon adsorption-desorption method but the shape of particles by transmission electronic microscopy

Acknowledgements Many thanks to my colleagues: Oskars Bikovens, Andris Vēveris and the one of leading experts of low temperature plasma physics and tehnology Academician of the ALS Jānis Grabis. The research was done withouth any financial support