hydrofluoric acid leaching for silica

hydrofluoric acid leaching for silica

Silica recovery from waste obtained in hydrofluoric acid ...

1996-6-1  Introduction of refined waste silica, obtained from synthesis of hydrofluoric acid into urethan elastomers brought about a regular increase in tensile strength parameters, such as, stress at 100% elongation (Module-100), tensile strength, relative elongation, hardness, etc. [27]. 48 A. Krysztafkiewicz et al. /Journal of Hazardous Materials 48 ...

Read More
A hydrofluoric acid-free method to dissolve and quantify ...

2019-5-28  An often-insurmountable obstacle for SiO2-NP fate and hazard research is the challenging analytics of solid particulate silica species, which involves toxic and corrosive hydrofluoric acid (HF).

Read More
Re-generation of hydrofluoric acid and selective ...

2004-11-25  The HF spent leaching solution is mixed with an aqueous solution containing Al(NO 3) 3.The Al 3+ ions combine with all free fluoride (F −), fluoride present as excess HF, and fluoride which is bound to Si(IV).This is due to the high-stability constants of AlF 2+ and AlF 2 +.The Si precipitates from solution as silica gel, which is filtered from solution.

Read More
Improvement of Impurities Removal from Silica Sand by ...

2011-4-5  The hydrofluoric acid (HF) was chosen for its chemical compatibility with silica (highly hydrophobic). It removes the most possible impurities, while leaving the molecular structure of silica intact. The second acid attack by hydrochloric acid (HCl) or sulfuric acid (H2SO4) is intended to remove the residual impurities (Fe, Al, and Ti) in solution.

Read More
Acid leaching of silica sand - Laboratory Testing ...

2021-11-18  Acid leaching of silica sand (4 replies) P. mallap. 5 years ago. ... If no results, you may need to look at hydrofluoric acid leaching, which is essentially a health, safety and environmental concern, potential liability. Try avoiding. In all scenarios, you will need to test at 2

Read More
Influence of Hydrofluoric Acid Leaching and Roasting on ...

In acid leached specimen (Figure 6c), the concentration of iron and sulfur are higher over the rest of the elements , implicating the ineffectiveness of hydrofluoric acid leaching on pyrite. The concentration of silicon (Si), aluminum (Al), fluorine (F), and oxygen elements in acid leached specimen presents the newly formed minerals and ...

Read More
Silica and Iron Recovery from a Residue of Iron Ore

2017-6-9  [6], purification of silica from flotation residue may be performed by acid leach-ing with percolation using a mixture of hydrofluoric acid (HF) and hydrochloric acid (HCl) followed by an alkaline washing with sodium hydroxide (NaOH). Santos et al. [7] evaluated the performance of leaching for purification of metal-

Read More
The Precipitation of Silica from Acidic Zinc Leach Liquors

It was found that a maximum zinc extraction (95% Zn) was obtained at a 4.5 M concentration of sulphuric acid in 3 h leaching at 70°C, keeping the solid:liquid weight ratio at 1:5 Iron and ...

Read More
The Precipitation of Silica from Acidic Zinc Leach Liquors ...

A solution of monosilicic acid (Si (OH) 4) was produced by leaching willemite (Zn 2 SiO 4) in sulphuric acid. Precipitation was monitored by measuring the turbidity and silica concentration in solution at regular intervals. Transmission Electron Microscopy (TEM) was used to examine the precipitate morphology. Variables known to influence silica ...

Read More
Solubility of SiO2. What should I do for getting a clear ...

2021-11-26  18th May, 2017. Yuri Mirgorod. Southwest State University (Russia) Silicon oxide is an acid oxide. Therefore, it dissolves in alkaline solutions. NaOH + SiO2 = Na2SiO3 +

Read More
Experiment ResearchStudy on Removing of Silica

According to the difficulty in removing silicic impurity for microcrystalline graphite, research of purification through alkali roasting binding with hydrofluoric acid was carried out. The amount of hydrofluoric acid and alkali contribute most to the effect of purification. Temperature and time of alkali roasting and acid leaching were all found the prominent factors to the effect of ...

Read More
EVALUATION OF WASTE SILICA PRECIPITATED IN THE

The leaching of the mentioned ions from silica gel waste to the liquid medium was achieved by the application of different techniques: (1) leaching under static conditions; (2) leaching under ...

Read More
Improvement of Impurities Removal from Silica Sand by ...

2011-4-5  The hydrofluoric acid (HF) was chosen for its chemical compatibility with silica (highly hydrophobic). It removes the most possible impurities, while leaving the molecular structure of silica intact. The second acid attack by hydrochloric acid (HCl) or sulfuric acid (H2SO4) is intended to remove the residual impurities (Fe, Al, and Ti) in solution.

Read More
hydroflouric acid and silica Gold Refining Metal ...

2009-4-21  ok, I have this ore containing 63% Sio2. I learned from wiki that chemical reaction is as following. Sio2 + 4HF ----> SiF4 + 2H2o Sio2 + 6HF ----> H(SiF4) + 2H2o Now all the chemist here, what does above means in grams of silica and grams or litre of hydroflouric acid mixture? does this means...

Read More
Acid leaching of silica sand - Laboratory Testing ...

2021-11-18  Acid leaching of silica sand (4 replies) P. mallap. 5 years ago. ... If no results, you may need to look at hydrofluoric acid leaching, which is essentially a health, safety and environmental concern, potential liability. Try avoiding. In all scenarios, you will need to test at 2

Read More
Influence of Hydrofluoric Acid Leaching and Roasting on ...

In acid leached specimen (Figure 6c), the concentration of iron and sulfur are higher over the rest of the elements , implicating the ineffectiveness of hydrofluoric acid leaching on pyrite. The concentration of silicon (Si), aluminum (Al), fluorine (F), and oxygen elements in acid leached specimen presents the newly formed minerals and ...

Read More
METHOD 3052 MICROWAVE ASSISTED ACID DIGESTION

2021-6-25  2.1 A representative sample of up to 0.5 g is digested in 9 mL of concentrated nitric acid and usually 3 mL hydrofluoric acid for 15 minutes using mi crowave heating with a suitable laboratory microwa ve system. The method has several additional alternative acid and reagent combinations including hydrochloric acid and hydrogen peroxide.

Read More
The Precipitation of Silica from Acidic Zinc Leach Liquors ...

A solution of monosilicic acid (Si (OH) 4) was produced by leaching willemite (Zn 2 SiO 4) in sulphuric acid. Precipitation was monitored by measuring the turbidity and silica concentration in solution at regular intervals. Transmission Electron Microscopy (TEM) was used to examine the precipitate morphology. Variables known to influence silica ...

Read More
Additive-Driven Dissolution Enhancement of Colloidal ...

2012-2-22  (a) Colloidal silica is an amorphous solid (in contrast to the well-known and recognized mineral scales).7 (b) Colloidal silica is a random, three-dimensional polymer formed by Si−O bonds.8 (c) Silica forms not by cation−anion association, but by polycondensation of silicic acid.9 (d) Silica deposits in real systems (e.g., heat exchange tube

Read More
High-Silica Glass - an overview ScienceDirect Topics

High silica fiber and quartz fiber have similar chemical properties, and they can resist variety of halide, acid and weak base except for hydrofluoric acid and hot phosphoric acid. High silica and quartz fiber both have exceptional heat resistance properties and they do not melt and evaporate at 1649 °C.

Read More
Experiment ResearchStudy on Removing of Silica

According to the difficulty in removing silicic impurity for microcrystalline graphite, research of purification through alkali roasting binding with hydrofluoric acid was carried out. The amount of hydrofluoric acid and alkali contribute most to the effect of purification. Temperature and time of alkali roasting and acid leaching were all found the prominent factors to the effect of ...

Read More
Acid leaching of silica sand - Laboratory Testing ...

2021-11-18  Acid leaching of silica sand (4 replies) P. mallap. 5 years ago. ... If no results, you may need to look at hydrofluoric acid leaching, which is essentially a health, safety and environmental concern, potential liability. Try avoiding. In all scenarios, you will need to test at 2

Read More
A hydrofluoric acid-free method to dissolve and quantify ...

2019-5-28  As the commercial use of synthetic amorphous silica nanomaterials (SiO 2-NPs) increases, their effects on the environment and human health have still not been explored in detail.An often-insurmountable obstacle for SiO 2-NP fate and hazard research is the challenging analytics of solid particulate silica species, which involves toxic and corrosive hydrofluoric acid (HF).

Read More
METHOD 3052 MICROWAVE ASSISTED ACID DIGESTION

2021-6-25  2.1 A representative sample of up to 0.5 g is digested in 9 mL of concentrated nitric acid and usually 3 mL hydrofluoric acid for 15 minutes using mi crowave heating with a suitable laboratory microwa ve system. The method has several additional alternative acid and reagent combinations including hydrochloric acid and hydrogen peroxide.

Read More
Study on the Preparation of Silica Using Residues of Oil

2021-3-18  resistance to acids, and is insoluble in water and acids (ex-cept for hydrofluoric acid). It is a kind of promising fine chemical widely used in rubbers, plastics, agrochemicals, paintings, medicines, and so on.4–6 Reports on the use of oil shale residue to make silica are prevalent in recent years. However, the experimental re-

Read More
Comparison of three wet-alkaline methods of digestion

2021-8-1  infra-red analysis, alkaline fusion and hydrofluoric acid/nitric acid methods. Introduction the assimilated silica in frustules as an amorphous polymorph of silica (Werner. 1977), Silica occurs in water in the soluble, colloidal and Recent studies of silica dynamics point to the particulate forms.

Read More
EVALUATION OF WASTE SILICA PRECIPITATED IN THE

2005-10-20  the course of hydrofluoric acid production, and its possible use as an elastomer filler. The process underwent in the fluosilicic acid-sulphuric acid system. The silica surface-occluded water soluble fluoride compounds were washed off in hot water, on vacuum filters. The obtained product manifested much better physicochemical parameters (i.e., more

Read More
Preparation of Porous Silicon from Porous Silica Glass via ...

2017-7-2  The powdered porous silica glass was reduced to silicon and magnesium silicide at temperatures higher than 600 °C. The silicon was isolated by the hydrochloric acid treatment and the subsequent hydrofluoric acid treatment for the reduction products. The SEM observation revealed that the prepared silicon had a porous structure.

Read More
Additive-Driven Dissolution Enhancement of Colloidal ...

2012-2-22  (a) Colloidal silica is an amorphous solid (in contrast to the well-known and recognized mineral scales).7 (b) Colloidal silica is a random, three-dimensional polymer formed by Si−O bonds.8 (c) Silica forms not by cation−anion association, but by polycondensation of silicic acid.9 (d) Silica deposits in real systems (e.g., heat exchange tube

Read More
Development and evaluation of an IgY based silica matrix ...

Silica surface functionalization was carried out with hydrofluoric acid (HF), ammonia, 3-aminopropyl triethoxysilane (APTES) and glutaraldehyde (GA). The RSM optimized matrix functionalization parameters for HF, ammonia, APTES and GA were

Read More