Optical Glass Production
Potassium nitrate is used as a special glass strengthening agent
Product properties: Crystalline powder or white granules, with a pungent and salty taste and a cool sensation, slightly hygroscopic, readily soluble in water, absorbs heat when dissolved in water, and the aqueous solution is neutral; insoluble in anhydrous ethanol and ether; relative density 2.11, melting point 334℃.
Product application: It is used as a special glass strengthening agent for mobile phones, tablet computer touch screens, optical glass, watch glass, etc.
Product packaging: 25/50KG plastic woven bags. Customized packaging is also available upon customer request.
| Project | Indicator | ||||
| IClass | Ⅱ Class | ⅢClass | |||
| IType | Ⅱ Type | ||||
| Potassium Nitrate (KNO₃) (on a dry basis) w/% ≥ | 99.8 | 99.6 | 99.4 | 98.5 | |
| Water Content w / % ≤ | 0.10 | 0.10 | 0.15 | 0.10 | |
| Water-insoluble Matter w/% ≤ | 0.01 | 0.01 | 0.03 | 0.02 | |
| Chloride (as Cl) w/% ≤ | 0.01 | 0.02 | 0.02 | 0.02 | |
| Sulfate (in SO₄) w/% ≤ | 0.005 | 0.005 | 0.01 | 0.01 | |
| Carbonate (as CO₃) w/% ≤ | 0.01 | 0.01 | 0.01 | 0.45 | |
| Ammonium Salt (measured in NH₄) w% ≤ | 0.02 | 0.07 | 一 | 一 | |
| Moisture Absorption Rate w/% ≤ | 一 | 0.20 | 0.25 | 一 | |
| Looseness (through a 4.75mm test sieve) w/% ≥ | 一 | 一 | 一 | 95 | |
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Optical glass strengthening involves the exchange of sodium ions on the glass surface with potassium ions in molten potassium nitrate salt. Since the radius of potassium ions is larger than that of sodium ions, potassium ions replace sodium ions in the glass, causing the surface to “squeeze” and expand, forming a compressive stress layer, thereby achieving the purpose of increasing the strength of the glass surface. During the glass strengthening process, the purity of potassium nitrate has a very significant impact on ion exchange. If the purity of potassium nitrate is insufficient, there will be more impurities such as sodium, calcium and magnesium, which will interfere with the exchange of potassium and sodium ions and affect the strengthening effect of glass. Therefore, the purity requirement for potassium nitrate used in optical glass is extremely high.
Our company adopts a new technology for potassium nitrate production independently developed to produce high-quality chemically tempered potassium nitrate, with a main content of over 99.9%, extremely low impurities, and sodium, calcium and magnesium ions all below 40ppm. Outstanding quality and powerful performance can enhance salt bath activity, increase strengthening depth, shorten strengthening time, extend service life, and improve flexural strength, surface hardness and other properties. With high-purity quality, it is superior to other similar products.
We can offer glass strengthening technology solutions. Based on the brand, composition and thickness of the glass, we recommend the usage temperature, time and different accelerators and protectants. We provide corresponding composite strengthening solutions for different brands of glass to ensure good quality and long furnace life.
