Method for reducing and controlling hexafluorosilicate concentration during the polishing of glass objects in a polishing bath containing sulphuric acid and hydrofluoric acid

A hydrofluoric acid and sulfuric acid technology, applied in the field of hexafluorosilicate ions, can solve the problems of reducing the polishing speed and the ratio of fluoride ions, and achieve the effect of reducing the ratio of fluoride, reducing evaporation, and shortening the entire process.

Inactive Publication Date: 2005-08-31
埃里希・扎尔茨勒 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This results in a decrease in the fluoride io

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Example 1: H 2 SiF 6 Precipitation / neutralization with potassium fluoride or potassium sulfate

[0039] The average weight of glass measuring cups is between 300-400g. During the polishing process, the average amount of glass removed is between 5% and 6%. If the glass weighs 300g, the glass removes 15-18g / cup, and for a glass weighing 400g, the glass removes 20-25g / cup. Since the average loading of each batch is about 200 pieces of glass, 3000-4800g of glass will be removed for each batch of 200 pieces of glass loaded. SiO in lead crystal glass 2 The ratio is generally between 50% and 55%. That is, about 1500-2640g SiO is removed per batch 2 . 1500g SiO to be removed for dissolution 2 , requires 3000gHF, while dissolving 2640gSiO to be removed 2 Then 5280 g HF is required, which is equivalent to acid consumption of about 3.5 L-7 L of HF (75%). This also means that a combined initial formation of 3600-5900 g H per batch in the polishing and rinse baths 2 SiF ...

Embodiment 2

[0043] Example 2: H 2 SiF 6 Precipitation / neutralization with aluminum sulfate

[0044] h 2 SiF 6 The precipitation can also utilize Al 2 (SO 4 )accomplish. Thanks Al 2 SiF 6 The solubility is significantly lower than that of K 2 SiF 6 , so Al 2 (SiF 6 ) 3 Form precipitation is preferred. However, since AlF 3 The solubility of is very low compared with KF, so when using Al 2 (SO 4 ) 3 Precipitation should accurately determine H before precipitation 2 SiF 6 ratio to avoid simultaneous precipitation of free HF required for polishing. However, precipitation of H using KF 2 SiF 6 Although not very effective, there is no problem of co-precipitation of fluoride.

Embodiment 3

[0045] Embodiment 3: the precipitation of zinc and oxalic acid

[0046] The ratio of zinc oxide in known glass compositions is generally 1.0% to 2.5%. Glass removal averages between 5% and 6% during polishing operations. Thus, if the glass weighs 300g, the glass removal is between 15-18g / cup, whereas if the glass weighs 400g, the glass removal is 20-25g / cup. Thus, for an average load of about 200 glasses per batch, between 3000-4800 g of glass is removed per batch of 200 glasses. The ratio of ZnO in lead crystal glass is generally between 1.0% and 2.5%. That is, about 30-120 g of ZnO was removed per batch. In order to precipitate 45g of ZnO present in polishing acid and sulfuric acid rinse baths to 114g of ZnSiF 6 , need 92g potassium oxalate (K 2 C 2 o 2 ), and in order to precipitate the existing 120gZnO into 305gZnSiF 6 , need 245g potassium oxalate. If potassium oxalate is unavailable, about 50 g oxalic acid (or 133 g oxalic acid for 120 g ZnO) can also be used to...

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PUM

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Abstract

The invention relates to a method for reducing and controlling the concentration of hexafluorosilicate ions arising when glass objects are polished in a polishing bath containing sulphuric acid and hydrofluoric acid. Potassium floride, potassium sulphate, sodium fluoride, sodium sulphate or aluminium sulphate is added to the polishing bath or sulphuric acid rinsing bath in quantities such that a drop in the concentration of fluoride ions below the optimum working range is avoided.

Description

technical field [0001] The present invention relates to a method for reducing and controlling the formation of hexafluorosilicate ions when polishing glassware in a polishing bath containing sulfuric acid and hydrofluoric acid, wherein a certain amount of potassium fluoride, potassium sulfate, sodium fluoride , sodium sulfate, or aluminum sulfate is added to the polishing bath or sulfuric acid rinse bath, so as to avoid the fluoride ion concentration falling below the optimum working range. Background technique [0002] It is known to polish glass articles chemically using polishing baths containing sulfuric and hydrofluoric acids. Due to the reaction with the glass components that occurs during acid polishing, a layer of salt is formed on the surface of the glass, which consists essentially of sulfate, fluoride, and fluorosilicate of cations contained in these glasses. composition. This salt layer must then be removed by a rinsing process so that it does not interfere wit...

Claims

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Application Information

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IPC IPC(8): C03C15/00C03C15/02
CPCC03C15/02
Inventor 埃里希·扎尔茨勒马库斯·扎尔茨勒
Owner 埃里希・扎尔茨勒
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