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hydrofluoric acid silica separation

Purification of dilute hydrofluoric acid by commercial ion ...

PDF | This paper describes the results from an experimental study of the purification of dilute hydrofluoric acid (5 wt.%) by ion exchange. Hydrofluoric acid was prepared by dilution from ...[...]

Effect of Hydrofluoric Acid in Oxidizing Acid Mixtures on ...

Effect of Hydrofluoric Acid in Oxidizing Acid Mixtures on the Hydroxylation of Silicon Surface ... the four acid mixture systems generated surfaces with comparable hydrophilicity, controlled oxide growth and reduced surface ... the silica surface.4 Nitric acid treatment is recommended by the[...]

Can hydrofluoric acid be used in HPLC - Chromatography Forum

Jun 06, 2011· You have no notifications See All. Quick links. FAQ; Get in Touch with Us[...]

Silicon dioxide(SiO2) and it's chemical reactions

Silica is converted to silicon by reduction with carbon. Fluorine reacts with silicon dioxide(SiO 2) to form SiF4 and O2 whereas the other halogen gases (Cl2, Br2, I2) are essentially unreactive.. SiO 2 is attacked by hydrofluoric acid (HF) to produce hexafluorosilicic acid:. SiO 2 + 6 HF → H2SiF6 + 2 H2O.. HF is used to remove or pattern SiO 2 in the semiconductor industry.[...]

Hydroflouric Acid Recovery System Pilot Plant Design Project

Project Synopsis. Prepare a process design package for a small, continuous hydrofluoric acid (HF) recovery system to reclaim valuable spent acid from the manufacturing process. ... During the separation process, the HFS dissociates (decomposes) to HF and silica tetrafluoride (SiF 4).[...]

Hydrofluoric Acid | Office of Environmental Health and Safety

Hydrofluoric acid is an aqueous inorganic acid solution commonly used in research and industry for its ability to etch silicon compounds. It is an essential tool for semiconductor and electronic fabrication, mineral processing and glass etching. In addition to its useful properties, hydrofluoric acid also poses severe health risks upon exposure.[...]

HYDROFLUORIC ACID - atmos.umd.edu

HOW TO TREAT HYDROFLUORIC ACID BURNS: It has been conclusively shown (references 1,2,3 and 4 below) that flushing the affected area with water for one minute and then massaging HF Antidote Gel into the wound until there is a cessation of pain is the most effective first aid treatment available.[...]

Selective Flotation Separation of Feldspar in Non Fluoride ...

In the conventional flotation separation of feldspar-quartz, hydrofluoric acid is used to suppress quartz and activate feldspar, and a long chain amine salt (acetate or chloride) is used as a collector. The bulk of amine collectors used in current feldspar operations are …[...]

Description of chemical precipitation mechanisms and their ...

Recent studies have shown that the reaction of clay with hydrofluoric (HF) acid is more complex than was earlier believed. It has been found that fluosilicic acid, generated during initial dissolution of clay, reacts with additional clay, extracting aluminum and depositing hydrated silica.[...]

Re-generation of hydrofluoric acid and selective ...

Re-generation of hydrofluoric acid and selective separation of Si(IV) in a process for producing ultra-clean coal ... in coal has been developed. The technique first uses aqueous hydrofluoric acid (HF) to react with aluminosilicates and quartz to form fluoride complexed Al and Si species in solution. ... silica generation and HF re-generation ...[...]


HYDROFLUORIC ACID attacks glass and any other silica containing material. May react with common metals (iron, steel) to generate flammable hydrogen gas if diluted below 65%. Reacts exothermically with chemical bases (examples: amines, amides, inorganic hydroxides). Can initiate polymerization in …[...]

Hydrofluoric acid (HF) reacts with silicon dioxide to ...

Dec 30, 2015· Hydrofluoric acid (HF) reacts with silicon dioxide to produce silicon tetraflouride and water. How do you write the balanced equation for this reaction?[...]

US5242670A - Method for hydrofluoric acid digestion of ...

A process for hydrofluoric acid digestion of inorganic silica/alumina matrix material for the production of silicon tetrafluoride and aluminum fluoride comprises the initial step of reacting the matrix material with hydrofluoric acid, to form silicon tetrafluoride gas and a solution/slurry containing aluminum fluoride, undigested oxides, and additional soluble and insoluble fluoride materials.[...]

Hydrofluoric acid - Wikipedia

Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water.It is a precursor to almost all fluorine compounds, including pharmaceuticals such as fluoxetine (Prozac), diverse materials such as PTFE (Teflon), and elemental fluorine itself. It is a colourless solution that is highly corrosive, capable of dissolving many materials, especially oxides. ...[...]

Dissolution of silicate minerals by hydrofluoric acid ...

Dissolution of silicate minerals by hydrofluoric acid. ADVERTISEMENT. Log In ... Dissolution of silicate minerals by hydrofluoric acid. William E. Kline, and H. Scott Fogler. Ind. Eng ... [HCl] = 2−8 M) proceeds through two distinct steps. First, the monomeric form of silica is quickly depleted from solution as it polymerizes to form primary ...[...]

Silicon Dioxide Etch using Buffered Hydrofluoric Acid

the rinse water into the "dilute acid/base waste" 55 gallon HDPE drum. 3.6 Return all labware to its proper location. 3.7 Wipe up any drips in the area with chemical wipes and dispose in either acid trash. 4.0 Storage: 4.1 Buffered Hydrofluoric acid should be stored in the acid cabinet in a tightly capped polyethylene bottle. 5.0 Waste ...[...]


Waste silica was sampled directly from production of hydrofluoric acid, involving decomposition of fluosilicic acid using sulphuric(VI) acid. The silica was subjected to purification by removal of post-production contaminations (HF and H2SiF6 in particular). Since hydrofluoric acid and fluosilicic acid are well soluble in water, the[...]

Separation and Purification of Quartz from Whole Rock

Separation and Purification of Quartz from Whole Rock ... this step after the phosphoric acid boiling and the first two hydrofluoric acid leaches so as to reduce the total sample size before this step. ... of the beaker (this film of supersaturated silica solution), …[...]

Sample Preparation Problem Solving for Inductively Coupled ...

May 01, 2012· The majority of applications of inductively coupled plasma–mass spectrometry (ICP-MS) for elemental analysis utilize liquid sample introduction whether or not the original sample was a liquid. The relative ease or difficulty of a given analysis depends on several factors including the matrix and the chemistry of the analyte.[...]

Column Chromatography | Product & Services

The success of the separation completely depends on how you use the column properly. Silica gel is ideal for chromatographic separation through columns due to its high adsorption capacity and the compatible with materials excluding strong alkalis and hydrofluoric acid.[...]

Corrosion of Alumina in Aqueous Hydrofluoric Acid ...

A variety of alumina-based ceramics were evaluated for dissolution in an azeotropic aqueous hydrofluoric acid test protocol at temperatures up to 200°C.[...]

separation of silica sand from minerals

1. . hydrofluoric acid, and electrostatic separation) and "7" (silica sand production utilizing processing. Physical separation for upgradation of valuable minerals: a study on . mineral quartz to remove iron coating could be use as glasssands either the light mineral quartz or …[...]

Solved: Silicon Dioxide, SiO2, Reacts With Hydrofluoric Ac ...

Silicon dioxide, SiO2, reacts with hydrofluoric acid, HF, as shown in the equation: SiO2(s) + 4 HF(aq) SiF4(aq) + 2 H2O(l) a. How many grams of SiF4 can be produced by …[...]

Analysis of Nitric Acid in the presence of Hydrofluoric Acid

Analysis of Nitric Acid in the presence of Hydrofluoric Acid. A discussion started in 2002 but continuing through 2017. 2002. Q. I am trying to find methods of analysis of two Nitric Acid-Hydrofluoric Acid etching solutions (one of low HF consistency, i.e ~1 g/l HF in 200~g/l HNO3 and one of high HF consistency, i.e.~40 g/l HF in ~400 g/l HNO3).[...]

Hydrofluoric acid | HF - PubChem

Hydrofluoric acid is an irritant to the mucosa of the upper and lower portions of the respiratory tract. As in ocular tissues, concentrations as low as 5 mg/L (5 ppm) may produce irritation to the nasal mucosa. When hydrofluoric acid is present in concentrations greater than 48%, the solution fumes, adding to the volatile airborne fraction.[...]

IOS Press Effect of hydrofluoric acid (HF) concentration ...

Effect of hydrofluoric acid (HF) concentration to pores size diameter of silicon membrane Norhafizah Burham a,b,*, Azrul Azlan Hamzaha and Burhanuddin Yeop Majlis a a Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia 43600[...]

Rapid, Micro‐Methods to Estimate Plant Silicon Content by ...

By treating 0.5 g DW of a plant sample directly with 10 ml of a dilute hydrofluoric acid solution (HF solution, 1.5 M HF—0.6 M HCl), all the silica in plant (as much as 150 mg SiO 2) was dissolved within 1 h.After dilution of the extract with 40 mL of distilled water, the silica in the extract was measured by the spectrometric molybdenum yellow method.[...]

Wet etching of silicon dioxide: hydrofluoric acid etching

In microelectronic assembly fabrication applications, wet etching of silicon dioxide is typically carried out using a hydrofluoric acid solution. The silicon dioxide can react with room temperature hydrofluoric acid solution, but does not etch silicon substrate and complex silicon.[...]

emDOCs.net – Emergency Medicine EducationHydrofluoric Acid ...

Hydrofluoric acid (HF) is one of the most dangerous corrosive inorganic acids due to its ability to destroy body tissue. 1 It is well known for its ability to dissolve silica and glass and is used in numerous industrial processes (e.g. glass etching, brick cleaning, microchip etching, electroplating, ...[...]