2. 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%)

3. The Basic Components Of Rice Husks Ash
wt (%)
mg/kg
Error ± (%)
SiO2
90.50
905000
0.5
Al2O3
0.59
5900
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

4. 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

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

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

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

8. FT IR Spectra of Rice Husks

15. 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

17. 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

18. 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