DESC:*** Complete Specification ***

“Method of processing shot blasting fines to obtain utilizable non-hazardous products”

Cross references to related applications: This complete specification is filed further to patent application No. 202331056634 filed on 23/02/2024 and the entire content of the provisional specification filed therewith is incorporated herein in its entirety by way of reference.

Field of the invention
This invention belongs to the smelting industry, and relates generally to methodologies for management of hazardous wastes generated during smelting operations. Specifically, the disclosures hereunder are directed to an inventive and systematic process for treating shot blasting fines for salvaging their ferrous, fluoride, and carbon content for advantageous applications.

Definitions and interpretations
Before undertaking the detailed description of the invention below, it may be advantageous to set forth definitions of certain words or phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect, with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and certain definitions are set forth for this document, as follows: -
(a) “SBF” shall refer to Shot Blasting Fines, as generated from the processing of used anode butts in aluminum smelter units.

Background of the invention & Description of related art
Used anode butts are a by-product of the aluminum smelting industry and present significant environmental challenges due to their hazardous nature. State and central pollution boards mandate the safe disposal of these by-products to mitigate their environmental impact. Current processes typically involve shot blasting to remove the outer contaminated layers of used anode butts, after which the treated anode butts are stored for further processing to produce electrode paste, green anodes, and other related materials. During the handling and storage of these treated materials, considerable amounts of hazardous dust or SBFs.

SBFs can present a number of issues, including:
(a) Airborne Dust: Shot blasting fines are often very fine particles that can become airborne, posing environmental hazards. These fines can contaminate the air and create health risks for workers who may inhale them.
(b) Disposal: Improper disposal of shot blasting fines can result in environmental contamination. These fines often contain metals or chemicals that are harmful to ecosystems.
(c) Respiratory Issues: Workers exposed to airborne fines can suffer from respiratory problems. Prolonged exposure may lead to chronic conditions like asthma, bronchitis, or even lung disease.
(d) Eye and Skin Irritation: Fine particles can also irritate the skin and eyes, leading to discomfort or injury.
(e) Equipment Wear: Shot blasting fines can cause additional wear and tear on the equipment used in the blasting process. The accumulation of fines can clog filters and reduce the efficiency of the system.
(f) Contamination of Blasting Media: Fines can mix with the reusable blasting media (such as steel shot or grit), causing contamination and necessitating frequent cleaning or replacement of the media.
(g) Handling: Handling the fines often requires additional measures like air filtration systems, dust collectors, and specialized storage to prevent contamination and maintain safety.

Specific to the aluminum industry, the issues pertaining to SBFs can be listed as under-
(a) Contamination of Aluminum Surfaces:
a. Fines Contaminating Parts: Shot blasting fines can contaminate the aluminum workpieces if they are not adequately removed. This contamination can affect the quality of finished aluminum products, especially when the parts need to meet strict surface finish standards or undergo processes like painting or anodizing. Contamination could lead to poor adhesion of coatings or discoloration.
b. Surface Defects: The fine particles left on aluminum surfaces can also create defects or rough textures that interfere with the final quality of the aluminum parts.
(b) Environmental Concerns:
a. Airborne Dust: As with other materials, shot blasting fines in the aluminum industry can become airborne. This presents health risks for workers and poses environmental pollution concerns. Aluminum dust, especially if it contains oils or other chemicals, can be hazardous.
b. Recycling Issues: Aluminum shot blasting fines often contain mixed debris, oils, or other residues that complicate recycling efforts. When the fines are not properly separated, they can reduce the value of the recyclable material.
(c) Health and Safety Risks:
a. Inhalation Hazards: Fine particles of aluminum and other materials used in shot blasting (like steel shot) can pose significant health risks when inhaled. Chronic exposure to aluminum dust can lead to respiratory problems and lung conditions. Protective measures such as dust collection systems and respirators are essential.
b. Explosion Hazard: Aluminum fines, if mixed with oil or certain chemicals, may pose a risk of combustion or explosion in certain environments. This makes it critical to ensure proper handling, storage, and disposal of aluminum fines.
(d) Equipment and Maintenance Issues:
a. Clogging and Wear: Shot blasting fines can accumulate in the system, clogging filters or affecting the performance of the equipment. The fines can also degrade the performance of the blasting media over time, increasing maintenance costs and operational downtime.
b. Impact on Shot Blasting Equipment: Excessive fines can result in increased wear on shot blasting machines, requiring more frequent maintenance and replacements of components.

Reducing the amount of fines produced and implementing recycling or reusing practices can help minimize environmental impact and reduce costs. Proper disposal of shot blasting fines is essential, especially if the fines contain hazardous residues (such as oils or coatings). It is desirable that these fines are collected and disposed of in compliance with environmental regulations.
State Pollution Board and Central Pollution Boards of India and equivalent authorities abroad have various mandates for the same, hence safe disposal of said used anode butts is a global acute regulatory need of the industry.

Various protocols have been proposed for addressing the aforementioned needs, all commonly using shot blasting to remove the outer contaminated layer of said used anode butts. Post shot blasting, the treated used anode butts are stored to be utilized in further processing to produce electrode paste/green anodes etcetera. In course of time during handling and storage of said treated used anode butts, copious amounts of hazardous dust / fines are generated which must be treated effectively in order to mitigate grave environmental concerns that are imminent otherwise.

The solutions seen in state of art can eb summarized as under-
(a) Dust Collection Systems: To prevent airborne fines, facilities often use industrial dust collectors or filtration systems to capture and contain the particles. Use of centralized dust collection systems equipped with high-efficiency filters (such as HEPA filters) can capture aluminum shot blasting fines before they become airborne. Cyclonic dust collectors can effectively separate larger particles from the air before it reaches the filtration stage, reducing the load on the system.
(b) Regulatory Compliance: Ensuring the operation complies with health and safety regulations, including proper ventilation and personal protective equipment (PPE) for workers.
(c) Regular maintenance: Frequent cleaning of shot blasting equipment, along with scheduled checks of the media, ensures the system runs smoothly and minimizes the build-up of fines that could contaminate aluminum parts.
(d) Recycling: Shot blasting media can often be cleaned and reused, minimizing waste and reducing the need for new media, which can also reduce the production of fines. Efficient systems can clean and recycle the blasting media, reducing the generation of fines and maintaining the quality of the blasting process. Media separation ensures that the fines are separated from reusable shot, thereby reducing contamination.
(e) Minimizing Fines Generation: Adjusting shot blasting parameters, such as pressure and shot size, can help reduce the generation of fines. Fine-tuning these parameters can help optimize the process to reduce the amount of fines created during blasting.
(f) Improved Blasting Techniques: Exploring alternative blasting methods or advanced techniques like shot peening or using different abrasive materials can help minimize the production of fines.

The reader can appreciate that it would be advantageous to explore methods to recycle aluminum shot blasting fines, which can reduce waste and recover valuable materials

Prior art, to the extent surveyed, lists no patents that are intended to address the issues mentioned hereinabove. State-of-art therefore, does not list a single effective solution embracing all considerations mentioned hereinabove, thus preserving an acute necessity-to-invent for the present inventor/s who, as result of focused research, has come up with novel solutions for resolving all needs once and for all.

None of the aforesaid solutions has been implemented ideally, which is why the need for further development still persists, which has been the focus of targeted research by the applicant named herein.

Work of the applicant/s hereof, specifically directed against the technical problems recited hereinabove and currently part of the public domain including earlier filed patent applications, is neither expressly nor impliedly admitted as prior art against the present disclosures.

A better understanding of the objects, advantages, features, properties and relationships of the present invention will be obtained from the following detailed description which sets forth an illustrative yet-preferred embodiment.

Objectives of the present invention
The present invention is identified in addressing at least all major deficiencies of art discussed in the foregoing section by effectively addressing the objectives stated under, of which:

It is a primary objective to provide a method for transformation of hazardous wastes generated during smelting operations into utilizable valuable products.

It is another objective further to the aforesaid objective(s) that said method is environmentally safe, commercially viable, sustainable, not unduly complex, expensive, nor dependent on highly skilled personnel or equipment to implement.

The manner in which the above objectives are achieved, together with other objects and advantages which will become subsequently apparent, reside in the detailed description set forth below in reference to the accompanying drawings and furthermore specifically outlined in the independent claims. Other advantageous embodiments of the invention are specified in the dependent claims.

Brief description of drawings
The present invention is explained herein under with reference to the following drawings, in which:

FIGURE 1 is a flowchart illustrating the process logic and flow of the present invention.

Attention of the reader is now requested to the detailed description to follow which narrates a preferred embodiment of the present invention and such other ways in which principles of the invention may be employed without parting from the essence of the invention claimed herein.

Statement / Summary of the invention
The present invention provides a method for processing shot blasting fines (SBFs) generated during the aluminum smelting process. The method is designed to recover and utilize the ferrous, fluoride, and carbon components of the SBFs in an environmentally safe and economically beneficial manner, though a process sequence identified as:
(a) Salvaging Ferrous Content.
(b) Salvaging Fluoride and Carbon Content
(c) Processing Fluoride Fraction to form a flux
(d) Processing Carbon Fraction which can be used as fuel or mineralizer

Additionally, a pulse jet bag filter is used to collect fine dust particles, which are subsequently reused during the process itself. By treating SBFs in this manner, the process recovers valuable materials that can be put to beneficial use, reducing environmental impact and providing industrial-grade products from a typically hazardous waste stream.

Detailed description
Principally, general purpose of the present invention is to assess disabilities and shortcomings inherent to known systems comprising state of the art and develop new systems incorporating all available advantages of known art and none of its disadvantages.

As stated in the background section of this document, existing methods do not offer an effective solution for the treatment of SBFs, thus posing environmental risks if not properly addressed. The current invention aims to resolve this problem by providing a systematic process that salvages the ferrous, fluoride, and carbon content of SBFs for advantageous applications, thus converting these hazardous by-products into economically viable and non-hazardous materials.

Accordingly, this invention is directed specifically addressing methods for managing hazardous wastes generated during smelting operations. More particularly, this invention relates to a process for treating SBFs produced during the processing of used anode butts in aluminum smelting units, for the recovery and utilization of valuable materials such as ferrous, fluoride, and carbon.

According to the preferred embodiment hereof, the present invention is identified in an implementation pathway comprising the following steps:

Step 1. Salvaging Ferrous Content:
Shot Blasting Fines (SBFs) are passed through a magnetic separation unit, which segregates the ferrous content from the fines. The ferrous material obtained from this step is then directed to appropriate applications, such as feeding the steel-making industry, where it serves as a valuable resource.

Physical separation is employed here by passing the SBFs past magnets, whereby the ferrous content of said SBFs is segregated out and can be put to advantageous end-applications, including routing as a feed to the steel-making industry.

Step 2. Density Separation for Fluoride and Carbon Fractions:
The remaining material (either the SBFs after the ferrous content has been removed or the original SBFs) is subjected to density separation using a closed air classifier. This step effectively separates the fluoride and carbon components into distinct fractions.

Step 3. Processing Fluoride Fraction:
The fluoride fraction is mixed with hydrated lime and left to react over a period of 24 hours. This reaction forms a flux material that can be used directly in the smelting industry, providing a valuable resource for industrial operations that require fluxing agents.

Step 4. Processing Carbon Fraction:
The carbon fraction is compacted and agglomerated into briquettes. These briquettes can serve as a source of fuel or as a mineralizer in industrial processes, further adding to the economic viability of the process.

The system also includes a pulse jet bag filter that collects fine dust particles generated during the processing. These fine particles are recycled and reused in the process, reducing waste and improving efficiency.

In conclusion, the present invention provides an innovative solution for the treatment of shot blasting fines generated during aluminum smelting operations. By recovering ferrous, fluoride, and carbon materials, the invention converts hazardous waste into valuable, non-hazardous products with significant industrial utility. This process contributes to the sustainability and efficiency of the smelting industry while addressing pressing environmental concerns.

Industrial applicability
As the reader shall realize, this invention provides a method that ensures the safe and effective recovery of ferrous, fluoride, and carbon components from shot blasting fines, enabling their beneficial use in industrial applications while minimizing environmental impact.

The method described in this patent has significant industrial applicability in the aluminum smelting and steel-making industries. The salvaged materials, including ferrous content, fluoride flux, and carbon briquettes, are of high economic value and can be utilized in a variety of industrial applications. This process not only resolves the environmental hazards posed by shot blasting fines but also recycles these materials into useful products, contributing to sustainable industrial practices.

As will be realized further, the present invention is capable of various other embodiments and that its several components and related details are capable of various alterations, all without departing from the basic concept of the present invention.

Accordingly, the foregoing description will be regarded as illustrative in nature and not as restrictive in any form whatsoever. Modifications and variations of the system and apparatus described herein will be obvious to those skilled in the art. Such modifications and variations are intended to come within ambit of the present invention, which is limited only by the appended claims. ,CLAIMS:1] A method for processing shot blasting fines (SBFs) generated during aluminum smelting operations, comprising the steps of:
(a) Passing the SBFs through a magnetic separator to salvage the ferrous content;
(b) Subjecting the remaining SBFs to density separation to obtain discrete fractions of fluoride and carbon;
(c) Mixing the fluoride fraction with hydrated lime and allowing the mixture to react for a period of 24 hours to form a flux; and
(d) Compacting and agglomerating the carbon fraction into briquettes for use as fuel or mineralizer.

2] The method for processing shot blasting fines (SBFs) generated during aluminum smelting operations as claimed in claim 1, further comprising the step of collecting fine dust particles using a pulse jet bag filter and recycling said particles in the process.

3] The method for processing shot blasting fines (SBFs) generated during aluminum smelting operations as claimed in claim 1, wherein the salvaged ferrous content is routed to the steel-making industry for use as a feedstock.

4] The method for processing shot blasting fines (SBFs) generated during aluminum smelting operations as claimed in claim 1, wherein the flux formed from the fluoride fraction is used in the smelting industry.

5] The method for processing shot blasting fines (SBFs) generated during aluminum smelting operations as claimed in claim 1, wherein the briquettes formed from the carbon fraction are used in industrial applications as fuel or mineralizer.