Processing of Alumina Refinery Waste: Red Mud

Processing of Alumina Refinery Waste: Red Mud

Supply chain management

PREFACE

Red mud is a harmful waste to the environment generates during refining of bauxite to yield alumina.  As the percentage of alumina found in bauxite ore is generally between 30-50%, approximately one to two tons of red mud is generated for every ton of alumina produced. Being harmful and produced in large quantities, red mud poses a huge environmental challenge for disposal.

Conventionally, red mud produced is pumped into clay-lined dams or dykes, and allowed to dry naturally. Thus, for the conventional disposal of red mud requires large open land. It causes additional problems especially for refineries with limited land space. Now a days, it stacked by using red mud filter press. It is an expensive and medium term solution, may pose serious problem for long term sustainability.

Over the years, there have been several attempts are made to find alternate use of red mud and still no commercially viable route has been established to process the red mud in proportion to its bulk generation.  The most promising and widely tested process is neutralization of red mud and returning it to soil as a harmless material.

As part of one more attempt, experiments are carried out for neutralizing the red mud generated in one of the Refinery of Hindalco Industries Limited, situated in Odisha. In the said attempt, series of experiments were conducted by using industry effluent & indigenous resources and found that in some of the experimental runs pH of red mud lowered to the range 7.5 to 8.5 from 11.

Table of Contents

PREFACE        

BACKDROP        

ALUMINA MANUFACTURING PROCESS        

NARRATIVE INCIDENCE        

A GREENFIELD REFINERY        

HUMAN PROCESS INTERVENTIONS (External)        

STRATEGIC INTERVENTIONS (Internal)        

CONFRONTATION TO COLLABORATION        

ACHIEVEMENT & ACCOLADES        

REFERENCES        

BACKDROP

What is "Red Mud"?

"Red Mud" is called a by-product/waste that derives from the alumina producing industries. It is called "Red" because usually has a red color (due to iron oxides) and "Mud" because it is a slurry. It is often also named "Bauxite Residue" whereas proprietary names of processed Red Mud can be found, such as "Bauxsol"™ (Virotec), "Cajunite"™ (Kaiser Aluminium), "Bauxaline"® (Aluminium Pechiney), "Ferroalumina" (Aluminium de Grece) etc.