The standard delineates the criteria and evaluation techniques for by-product gypsum utilized in the production of plaster, blocks, and boards. It specifies chemical composition thresholds, sampling methods, packaging, and labeling guidelines concerning phosphogypsum, fluorogypsum, and marine gypsum variants. This specification is crucial for professionals controlling quality and manufacturing construction materials to guarantee the safe and efficient use of by-product gypsum in building projects.
Overview
The standard delineates the criteria and evaluation techniques for by-product gypsum utilized in the production of plaster, blocks, and boards. It specifies chemical composition thresholds, sampling methods, packaging, and labeling guidelines concerning phosphogypsum, fluorogypsum, and marine gypsum variants. This specification is crucial for professionals controlling quality and manufacturing construction materials to guarantee the safe and efficient use of by-product gypsum in building projects.
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Frequently Asked
Per the standard’s Clause 3.1 Table 1, the following impurity limits apply to by-product gypsum types:
| Impurity | Phosphogypsum | Fluorogypsum | Marine Gypsum |
|---|---|---|---|
| P₂O₅ (%) Max | 0.40 | Not Applicable | Not Applicable |
| Fluoride (F) (%) Max | 0.40 | 1.0 | Not Applicable |
| Sodium Oxide (Na₂O) (%) Max | 0.10 | Not Applicable | Not Applicable |
| Potassium Oxide (K₂O) (%) Max | 0.20 | Not Applicable | Not Applicable |
| Organic Matter (%) Max | 0.15 | Not Applicable | Not Applicable |
| Chloride as NaCl (%) Max | 0.10 | Not Applicable | 0.10 |
| Calcium Sulfate Dihydrate (CaSO₄·2H₂O) (%) Min | 85.0 | 90.0 | 85.0 |
| pH (10% aqueous suspension) Min | 5.0 | 5.0 | 6.0 |
If impurity levels exceed these limits, the gypsum must undergo processing to reduce contaminants before use in plaster, blocks, or boards manufacturing.
According to the standard, sampling and testing for conformity involve the following steps:
This methodology ensures unbiased, statistically sound quality verification.
The standard mandates that by-product gypsum must be securely packed in appropriate bags or containers. Each package should be clearly marked with:
Furthermore, if the product bears the BIS Standard Mark, it signifies adherence to BIS’s inspection, testing, and quality standards, enhancing traceability and assurance during storage and distribution.
The standard covers three varieties of by-product gypsum:
Their chemical criteria differ as follows:
| Parameter | Phosphogypsum | Fluorogypsum | Marine Gypsum |
|---|---|---|---|
| P₂O₅ (%) Max | 0.40 | Not Specified | Not Specified |
| Fluoride (F) (%) Max | 0.40 | 1.0 | Not Specified |
| Na₂O (%) Max | 0.10 | Not Specified | Not Specified |
| K₂O (%) Max | 0.20 | Not Specified | Not Specified |
| Organic Matter (%) Max | 0.15 | Not Specified | Not Specified |
| CaSO₄·2H₂O (%) Min | 85.0 | 90.0 | 85.0 |
| Chloride as NaCl (%) Max | 0.10 | Not Specified | 0.10 |
| pH (10% suspension) Min | 5.0 | 5.0 | 6.0 |
Impurities exceeding these limits necessitate processing to achieve the standard’s quality benchmarks.
Phosphogypsum, a by-product from wet-process phosphoric acid production, presents significant environmental challenges primarily due to its potential to pollute water bodies. Improper disposal can introduce phosphates, fluorides, alkalies, and organic contaminants into soil and water, adversely affecting potable water, animal habitats, and agriculture.
The standard sets strict chemical thresholds for phosphogypsum to mitigate these risks, including limits on phosphorus pentoxide (≤0.40%), fluoride (≤0.40%), organic content (≤0.15%), minimum calcium sulfate dihydrate content (≥85%), and a pH not below 5.0 (10% aqueous suspension).
If these impurity levels are surpassed, phosphogypsum must be treated to reduce harmful substances before being utilized in construction or soil reclamation applications, ensuring environmental safety and material performance.
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