# Particle-Scale Magnetic Susceptibility and MLA Dataset – Norra Kärr Ore

## Overview

This folder contains particle-scale magnetic susceptibility and quantitative mineralogical data for the Norra Kärr ore. The data were generated to support geometallurgical analysis of magnetic separation behavior using particle-based characterization.

Two particle size fractions of the Norra Kärr ore are included:
- **NK1-3:** 500–1000 µm  
- **NK1-5:** 125–250 µm  

---

## Sample Material

The Norra Kärr ore is a peralkaline nepheline syenite-hosted mineral system characterized by complex mineral assemblages and predominantly paramagnetic mineral phases. The material exhibits significant mineralogical heterogeneity, making it suitable for particle-scale magnetic susceptibility analysis and geometallurgical studies.

---

## Experimental Methods Overview

**Magnetic classification:**  
- Frantz Isodynamic Separator

**Magnetic susceptibility measurements:**  
- Magnetic Susceptibility Balance (MSB)

**Mineralogical characterization:**  
- SEM-based Mineral Liberation Analysis (MLA)

Particles were separated into discrete magnetic susceptibility classes using the Frantz separator. Bulk magnetic susceptibility and mineralogical composition were determined for each class.

---

## Frantz Isodynamic Separator Settings and Magnetic Class Collection

Magnetic classes were collected by incrementally increasing the applied current of the Frantz Isodynamic Separator while maintaining fixed geometric and operational settings for each particle size fraction.

### Separator Operating Settings

- **Side slope angle: 14 degrees** fixed during separation  
- **Feed rate:** manually controlled to ensure stable particle flow  

---

### Magnetic Class Current Definition

Each magnetic susceptibility class corresponds to a specific Frantz current setting (Ampere), which defines the magnetic field strength at which particles were collected.

**Example:**
- `0.90 Amp.csv`  
  → Particles collected at a Frantz operating current of **0.90 A**.

---

### Unbounded Magnetic Classes

To ensure full coverage of the magnetic susceptibility spectrum:

- **`-HM` (High Magnetic / no lower limit):**  
  Lowest class; includes particles collected at the stated current and all particles with higher susceptibility.  

- **`-NM` (Non-Magnetic / no upper limit):**  
  Highest class; includes particles collected at the stated current and all particles with lower susceptibility.  

All current values used for class collection are reflected in the file and folder names within each sample directory.


## SEM-EDS (MLA) Measurement Conditions 

Automated mineralogical analysis of the WEEE slag sample was performed using SEM-based Mineral Liberation Analysis (MLA) under consistent and controlled SEM-EDS operating conditions.
However, the exact measurements conditions are not known.

---

## Folder Structure

/Norra_Karr
│── NK1-3/
│── NK1-5/
│── NK1-5_Feed/ (This folder contain particle data of feed sample - before separation)
│── README.md


Each sample folder contains the following structure:

/Sample_Folder
│── Magnetic susceptibility data/
│── MLA class-level data/
│── MLA particle-level data/
│── README.md

---

## Data Formats

- **Magnetic_Susceptibility:**  
  Class-average magnetic susceptibility measurements.

- **MLA_Class_Level:**  
  Modal mineralogical compositions per magnetic susceptibility class.

- **MLA_Particle_Level:**  
  Particle-by-particle MLA data provided as Excel files.

  - `*.csv` → mineral fractions in **weight percent (%)** (raw MLA output)  
  - `*_vol.csv` → mineral fractions converted to **volume percent (%)**

## Particle Size Units in MLA Particle-Level Data

All particle size–related parameters reported in the MLA particle-level Excel files are expressed in **micrometers (µm)**.

This includes, but is not limited to:
- Equivalent circle diameter (ECD)
- Feret diameters
- Particle length and width
- Area-derived size metrics reported by the MLA software

Particle sizes are derived from two-dimensional polished sections and represent projected particle dimensions in micrometers. Users should consider stereological effects when interpreting particle size distributions.

---

## Notes on Data Use

- Magnetic susceptibility values represent class-average measurements.
- MLA data are derived from two-dimensional polished sections and may be subject to stereological bias.
- Volume% data are provided for physically representative quantitative analysis.