Recovery of Synthetic Diamonds from Fines of Natural Stones Processing
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2024-06-26 |
| Journal | Revista de GestĂŁo Social e Ambiental |
| Authors | Victor Moza Ponciano, Alexandre Vianna Bahiense, Phillipe Fernandes de Almeida, Mateus Valentim Simmer Sopeletto, Viviana Possamai Della Sagrillo |
| Citations | 1 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis study successfully validates an innovative flotation methodology for recovering high-value synthetic diamonds from âFibroââthe fine waste generated by the ornamental natural stone processing industry.
- Value Proposition: Transforms millions of tons of inert industrial waste (Fibro) into a reusable, high-cost input (synthetic diamond powder), significantly advancing circular economy goals.
- Technical Feasibility: Demonstrated the technical viability of recovering synthetic diamonds (0.15-0.40 mm) using a bench-scale flotation process.
- Optimal Parameters: The most efficient operational condition was identified as Group 1: 35% solids during conditioning and 25% solids during the flotation stage.
- Recovery Achievement: Group 1 achieved an average concentrate recovery rate of 2.62%, showing a relative efficiency increase of > 13% compared to the higher solids concentration group (Group 2).
- Reagent Influence: Statistical analysis confirmed that the percentage of solids and the frothing agent (MIBC) were the most significant variables influencing recovery.
- Diamond Hydrophobicity: The collector reagent (kerosene) showed minimal influence on the process, which is attributed to the natural hydrophobicity of the synthetic diamond particles.
- Commercial Impact: Provides a pathway for the ornamental rock sector to enter a new market by reinserting recovered diamond grains back into the abrasive tool manufacturing supply chain.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Optimal Solids (Conditioning) | 35 | % | Group 1 (Highest efficiency) |
| Optimal Solids (Flotation) | 25 | % | Group 1 (Highest efficiency) |
| Average Recovery Rate (Group 1) | 2.62 | % | Recovery of diamond concentrate |
| Recovery Rate Standard Deviation (Group 1) | 0.24 | % | Measure of process stability |
| Efficiency Improvement (G1 vs G2) | > 13 | % | Relative efficiency increase of Group 1 |
| Diamond Grain Size Range | 0.15 to 0.40 | mm | Target particle size for recovery |
| Feed Material Mass (per test) | 400 (G1) / 500 (G2) | g | Mass of Fibro used per flotation run |
| Total Samples Tested | 18 | N/A | 32 factorial design across two solids groups |
| Flotation Cell Volume | 2 | L | Bench-scale equipment volume |
| Flotation Equipment Model | CFB 1000N | N/A | Engendrar bench flotation unit |
| Waste Classification (Fibro) | Class II B | NBR 10.004/2004 | Non-dangerous and inert waste |
Key Methodologies
Section titled âKey MethodologiesâThe research employed a structured experimental design (Design of Experiments - DOE) combined with Response Surface Methodology (MSR) to optimize the flotation process for synthetic diamond recovery.
-
Feedstock Sourcing and Preparation:
- Material: Fibro fines collected from the effluent treatment box of a granite processing plant (100% granite feedstock).
- Quantity: Over 500 kg of wet material collected, dried, and homogenized.
- Homogenization: Samples prepared using a Jones type quartet method.
-
Granulometric Classification:
- Material was wet-sieved according to NBR 7181/2:2018 standards.
- The target fraction for flotation was collected between the 28 mesh and 65 mesh screens (Tyler scale), corresponding to the size range of diamonds typically used in rock cutting tools.
-
Experimental Design (32 Factorial):
- Two primary variables were tested at three levels (-1, 0, 1): Collector quantity and Frother quantity.
- These tests were run across two distinct groups defined by solid percentage:
- Group 1 (Optimal): 35% solids (conditioning) / 25% solids (flotation).
- Group 2: 40% solids (conditioning) / 30% solids (flotation).
-
Reagent System:
- Collector: Kerosene (used to enhance hydrophobicity).
- Frother (Foaming Agent): Methyl Isobutyl Carbinol (MIBC) (used for efficient bubble generation and stability).
-
Flotation Procedure:
- Tests conducted in a 2 L bench flotation cell (Engendrar CFB 1000N).
- The process involved sequential stages: feeding of solids, addition of reagents, conditioning, aeration (bubble generation), and collection of the floated concentrate (foam).
-
Modeling and Analysis:
- Statistical analysis (Statistica 10.1) was used to model the data, determine the influence of variables (Pareto graph), and generate response surfaces to identify optimal reagent interaction levels.
Commercial Applications
Section titled âCommercial ApplicationsâThe successful recovery of synthetic diamond powder from industrial waste opens several high-value commercial avenues, primarily focused on resource circularity and industrial sustainability.
- Abrasive Tool Manufacturing:
- Direct reinsertion of the recovered diamond grains (0.15-0.40 mm) as a raw material for producing new diamond-impregnated cutting blades, wires, and polishing tools used in the ornamental rock sector.
- Industrial Sustainability and Circular Economy:
- Establishes a proven, scalable methodology for industrial waste valorization, reducing the environmental footprint associated with Fibro disposal.
- Mining and Mineral Processing:
- Provides a new, profitable mineral concentrate stream for companies operating in the ornamental stone industry, diversifying their product portfolio beyond finished rock slabs.
- Specialty Materials Market:
- The recovered synthetic diamond, characterized by its intact octahedral cube shape, can be marketed for other high-performance industrial applications requiring super-hard materials.
- Waste Management Cost Reduction:
- By converting a waste product into a co-product, companies can significantly reduce costs associated with landfill disposal and environmental compliance for Fibro.
View Original Abstract
Objective: The objective of this study is to investigate the flotation process of the fines from the processing of natural stones - Fibro, and to propose a methodology to recovery synthetic diamonds present in it. For this, this research analyzes the influence of the amount of solid mass in the pulp and the amount of reagents used in the process. Theoretical Framework: The productive chain of natural stones generates millions of tons of Fibro annually, which can cause environmental damage if not disposed of or treated properly. Considering that the principles of circular economy are relevant in the pursuit of sustainable development of the sector, it is emphasized that Fibro contains several mineral resources that can be used in other productive chains. In addition to the rock powders resulting from processing, there are other particles of interest such as synthetic diamond. The synthetic diamonds present in Fibro come from the diamond tools used in rock sawing and polishing. These diamond particles have a high added value, and some recovery methods have been implemented to capture these grains for reuse. Among the methods used for this purpose, flotation has obtained the best results in previous studies. Method: The methodology adopted for this research begins with the collection and sampling of the Fibro in the natural stone production industries. Then, this material was classified granulometrically through sieving, and the samples were then subjected to the flotation process. In flotation, the percentage of solids in the pulp and the amounts of collector and frother used in the process were tested. All untested parameters were kept constant, and only the variables under investigation were modified at different levels. The methodology followed an experimental design and it was applied regression models and response surfaces for data modeling. Results and Discussion: The results show that the most efficient solid percentage was 35% in conditioning and 25% in flotation. Regarding the quantities of reagents tested, the model generated by the response surface indicates which levels obtained the best results in terms of concentrate recovery rate. It was also noted that the amount of collector had little influence on the process, which can be inferred by the natural hydrophobicity of the diamond. Implications of the Research: The implications of this research include economic benefits for the natural stones industry from the possibility of entering a new market in the sector. As well as advances in circular economy by reusing industrial waste and developing new technologies for the use of these materials. These results have the potential to impact industrial sustainability and can expand the mining and metallurgy sector. Originality/Value: This study contributes to the mining industry by proposing an innovative flotation methodology to recover synthetic diamonds from the fines of processing of natural stones. The relevance and value of this research are evidenced by its ability to provide a practical and efficient solution, with potential positive impact on circular economy and industrial sustainability.