CALDUR® Silicate – Photometric
Silicate determination in water using a photometer (0.1-30 mg/l SiO₂)
Private customers can also find our range in our partner store Ampha-Analyse.
Reagent for CALDUR® Silicate – Photometric:
See also:
CALDUR® Silicate Test Set – Photometric
What is silicate measured for?
Silicate (SiO₂) is a naturally occurring water constituent that comes from the dissolution of rocks and minerals. Silicate is particularly critical in boiler water technology, as it can form glass-like deposits (silicate scale) at high temperatures and pressures, which are extremely difficult to remove.
In high-pressure boilers, the silicate content must be kept particularly low, as even low concentrations can lead to deposits on turbine blades. Typical limit values are 0.02-0.5 mg/l SiO₂ depending on the operating pressure.
Silicate control is also important in drinking water treatment and in the production of ultrapure water (e.g. for the semiconductor industry).
How does the test set work?
The CALDUR® Silicate Test Set – Photometric is based on the molybdate method. After adding three reagents to the water sample, a yellow silicomolybdate complex is formed within 8 minutes, the concentration of which is precisely determined using the WINLAB Data Line photometer.
Advantages of the CALDUR® test set
- Wide measuring range 0.1 – 30 mg/l SiO₂
Covers the range from boiler water to raw water
- 100 provisions per set
Economical for regular checks
- High precision due to photometric evaluation
Objective, reproducible measurement results with the WINLAB Data Line
- Proven molybdate method
Specific for dissolved silicate
Areas of application
Carrying out the measurement:
- Fill the round cuvette with sample up to the 10 ml mark
- Add 5 drops of reagent A and mix
- Add 3 drops of reagent B and mix
- Add 5 drops of reagent C and mix
- Wait for 8 minutes reaction time
- Insert the cuvette into the WINLAB Data Line photometer
- Start measurement – result is displayed directly in mg/l SiO₂
Tip for best results
Samples must be collected in plastic vessels – glass releases silicate and falsifies the measurement. Allow boiler water samples to cool down to room temperature before measuring.
Important notes
- Do not use glass jars – only plastic!
- Adhere exactly to the response time of 8 minutes
- Allow sample to cool to room temperature before measuring
- Wipe the cuvette with a lint-free cloth before measuring
- Phosphate in high concentrations can influence the result
- Requires WINLAB Data Line photometer (Art. 37-000100)
Measuring range
| Property | Value |
|---|---|
| Measuring range | 0.1 to 30 mg/l SiO₂ |
| Resolution | 0.1 mg/l |
| Method | Molybdate method, photometric evaluation |
In contrast to the colorimetric method (color chart), the photometer provides exact numerical values with a higher resolution. Intermediate values are calculated automatically – ideal for documentation and quality assurance.
Number of possible destinations
You can carry out 100 measurements with one CALDUR® Silicate Photometric Test Set.
This refers to the quantity of reagents contained.
Recommended limit values
| Application | Recommended silicate content |
|---|---|
| Low pressure boiler (< 20 bar) | < 5 mg/l SiO₂ |
| Medium pressure vessel (20-60 bar) | < 1 mg/l SiO₂ |
| High pressure boiler (> 60 bar) | < 0.5 mg/l SiO₂ |
| Feed water | < 0.02 mg/l SiO₂ |
Silicate deposits are particularly dangerous as they can hardly be removed using conventional cleaning methods. Regular inspection is therefore essential.
What to do if measured values are out of range?
Measured value > 30 mg/l
| Verduction | Execution | Calculation of the measured value |
|---|---|---|
| 1:1 | 5 ml sample + 5 ml silicate-free water | Measured value × 2 |
Measured value < 0.1 mg/l
Measured value is below the detection limit. For more sensitive measurements, please contact our technical support.
Specifications at a glance
| Property | Value |
|---|---|
| Parameters | Silicate (SiO₂) |
| Item number | 31-073522 |
| Method | Photometric (molybdate) |
| Measuring principle | Photometric evaluation with WINLAB Data Line |
| Measuring range | 0.1 to 30 mg/l SiO₂ |
| Resolution | 0.1 mg/l |
| Duration of analysis | 8 minutes |
| Number of provisions | 100 |
| Number of reagents | 3 |
| Packaging | Plastic bag |
| Scope of delivery |
|---|
| 3 reagent bottles (reagent A, reagent B, reagent C) with detailed labeling |
| 1 round cuvette (10 ml) |
| Detailed operating instructions (DE/EN) |
| Safety data sheets for all reagents |
| Resealable plastic bag |
Reagent details
| Reagent | Volume | Shelf life | Notes |
|---|---|---|---|
| Reagent A (molybdate) | 30 ml | 24 months (24M) | Molybdate reagent, shake before use |
| Reagent B (acid) | 10 ml | 24 months (24M) | Acid reagent, dose carefully |
| Reagent C (reducing agent) | 10 ml | 24 months (24M) | Shake before use |
Shelf life: The shelf life starts from the date of manufacture (printed on the bottle).
After opening, the reagents should be used within 12 months.
Store the test kit in a dry, cool place (10-25°C) and protected from direct sunlight.
Required accessories
The photometer is not included in the test set and is available separately.
Additional information
| Packaging | Plastic bag, Refill pack |
|---|---|
| Product category | Testset |
Flyer
Operating instructions
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