SN/T 5685-2024 in English
VALIDImport Metal Mineral Products and Their Main Solid Waste Mineral Phase Analysis Method Reflective Optical Microscopy
- Issued on:2024-12-31
- Implemented on:2025-07-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
$175.00
| Standard No: | SN/T 5685-2024 |
| Document status: | VALID |
| Title in English: | Import Metal Mineral Products and Their Main Solid Waste Mineral Phase Analysis Method Reflective Optical Microscopy |
| Title in Chinese: | 进口金属矿产品及其主要固体废物矿相分析方法 反射式光学显微镜法 |
| Language: | English |
| File Format: | Electronic (PDF) |
| Delivery: | Via email within 1~3 business days |
| Issued on: | 2024-12-31 |
| Implemented on: | 2025-07-01 |
| ICS Classification: | 73.060.01-Metalliferous minerals in general |
| Chinese Classification: | H24-Metallographic testing method |
| Professional Classification: | SN-Import&Export Inspection |
Introduction
Technical background and evolution of standards
As the latest technical specification released by the General Administration of Customs in 2024, this standard marks a major shift in the identification technology of imported metal mineral products in my country from traditional chemical analysis to microscopic morphological identification using a reflective optical microscope. Compared with the DZ/T0275 series of specifications, this document innovatively applies mineral phase analysis technology to the field of solid waste identification, and achieves non-destructive rapid screening by establishing a standardized optical sheet preparation process and a mineral feature database.
Core method principle
Based on the optical property differences of mineral reflection color (grayish white, light yellow, etc.) and internal reflection color (dark red, blue-green, etc.), observation was performed using a reflection optical microscope at 40-1000 times magnification:
| Observation parameters | Natural mineral characteristics | Solid waste characteristics |
|---|---|---|
| Crystal morphology | Automorphic/semiautomorphic crystals | Melt-like, rounded |
| Particle distribution | Regularly embedded | Disordered and uniformly dispersed |
| Surface structure | Complete cleavage surface | Honeycomb pores |
Key sample preparation technical specifications
The preparation of optical slices must strictly follow the four-level grinding system:
- Coarse grinding: 120# corundum for 3-5 minutes to remove cutting marks
- Medium and fine grinding: 150# corundum to obtain the basic plane
- Fine grinding: 600# corundum to achieve the prototype of the mirror surface
- Fine grinding and polishing: 1000# corundum + alumina polishing agent to eliminate micro scratches
A typical case shows that after the smelting dust sample was vacuum cold mounted, the light slice prepared with a 20mm diameter mold can clearly observe the hematite nodule structure of <5μm under a 40x objective lens.
Mineral identification index system
Establish a six-dimensional identification matrix:
| Indicator | Key technical points | Characteristic value of solid waste |
|---|---|---|
| Degree of crystallinity | Ratio of euhedral crystal | ≤30% |
| Reflectivity | Relative to standard mineral | Deviation＞15% |
| Particle size distribution | D90 value | ＜20μm |
| Structural type | GB/T30067 classification | Porous/melted |
Implementation recommendations and quality control points
Laboratory construction requirements: It is necessary to configure a vibration-proof platform (amplitude <2μm) and a constant temperature and humidity environment (23±1℃, RH45±5%). It is recommended to use a standard mineral light sheet for microscope calibration after every 200 tests.
Staff training points: It is necessary to master the reflectance spectral feature library of more than 300 common minerals, especially the differential diagnostic features of iron oxides (hematite, magnetite) and smelting by-products.
In the implementation of the standard, the high-temperature treatment characteristics listed in Appendix B should be focused on: such as typical solid waste morphological markers such as fish-back-shaped hematite and sponge-like metal balls.
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