Process and apparatus for obtaining silicon from fluosilicic acid

Patent · Tue Jul 16 00:00:00 EDT 1985

OSTI ID:865515

Sancier, Kenneth M ^[1]

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1. Menlo Park, CA

Process for producing low cost, high purity solar grade Si wherein a reduction reaction, preferably the reduction of SiF.sub.4, by an alkali metal (liquid Na preferred) is carried out essentialy continuously by injecting of reactants in substantially stoichiometric proportions into a reaction chamber having a controlled temperature thereby to form a mist or dispersion of reactants. The reactants being supplied at such a rate and temperature that the reaction takes place far enough away from the entry region to avoid plugging of reactants at the entry region, the reaction is completed and whereby essentially all reaction product solidifies and forms a free flowing powder before reaction product hits a reaction chamber wall. Thus, the reaction product does not adhere to the reaction chamber wall or pick up impurities therefrom. Separation of reaction products is easily carried out by either a leach or melt separation process.

• DOE Contract Number: 954471-NAS 7-100
• Assignee: SRI International (Menlo Park, CA)
• Patent Number(s): US 4529576
• Application Number: 06/453,457
• OSTI ID: 865515
• Country of Publication: United States
• Language: English

Related Subjects

process
apparatus
obtaining
silicon
fluosilicic
acid
producing
cost
purity
solar
grade
reduction
reaction
preferably
sif
alkali
metal
liquid
na
preferred
carried
essentialy
continuously
injecting
reactants
substantially
stoichiometric
proportions
chamber
controlled
temperature
form
mist
dispersion
supplied
rate
takes
entry
region
avoid
plugging
completed
whereby
essentially
product
solidifies
forms
free
flowing
powder
hits
wall
adhere
pick
impurities
therefrom
separation
products
easily
leach
melt
reaction takes
na preferred
fluosilicic acid
controlled temperature
free flowing
separation process
reaction chamber
alkali metal
reaction product
reaction products
chamber wall
solar grade
purity solar
entry region
obtaining silicon
reduction reaction
melt separation
free flow
avoid plugging
impurities therefrom
silicic acid
liquid na
/423/136/422/