Manganese
Cato Ridge Alloys
Cato Ridge Alloys (Pty) Ltd is a joint venture between Assmang, which holds a 50% interest, Mizushima Ferroalloys Company Limited, which holds a 40% interest and Sumitomo Corporation, which holds 10%. Assmang is responsible for the day-to-day management of the venture.
The company was formed during 1996 for the production of refined ferro-manganese utilising high carbon ferro-manganese from the Cato Ridge Works as the feedstock.
The construction of the plant started in 1997 and the first refined ferro-manganese for export was produced at the beginning of 1998.
the ladle into the convertor.
Production
Production of refined ferro-manganese is carried out in a top blown bottom stirred converter by preferential oxidation of carbon. Mizushima Ferroalloys of Japan supplied the technology utilised. The plant has a capacity to produce up to 60 000 tons of refined ferromanganese per annum. The hot metal (high carbon ferro-manganese) is supplied mainly from the Works' No.5 and 6 furnaces with No. 3 and 4 furnaces utilized as backup when required. The gasses and fluxes utilised are procured locally.
The process is controlled with a PLC based supervisory system to optimise the manganese yield. The metal is tapped into a ladle and cast into fine metal beds from where it is removed and allowed to cool. It is then crushed and sized to customer requirements. The slag generated is utilised as an ore feed to the furnaces due to the high manganese content. The dust from the off gas filtration unit is sold directly for use as pigment in the brick/ceramic industry or stockpiled for future use.
Refined ferro-manganese specification
Two grades of refined ferromanganese lumpy material are produced. The typical analyses are:
| Medium Carbon FeMn | Low carbon FeMn | ||
| Manganese | +80% | +80% | |
| Iron | 16.5 | 17.2 | |
| Silicon | 0.30 | 0.30 | |
| Phosphorous | 0.08 | 0.08 | |
| Sulphur | 0.005 | 0.005 | |
| Carbon | <1.5% | <1.0% |
The fine metal generated (-6mm product) is sold to a different manganese specification due to the nature of the product.
The metal is sized to the customer's specification in the crushing and screening plant. Typical standard sizes are:
| -100+25mm |
| -75+25mm |
| -50+10mm |
| -35+10mm |
| -25+5mm |
| -6mm |
The metal is loaded onto trains in bulk and railed to Richards Bay harbour where it is loaded onto vessels. A facility also exists to containerise ferromanganese, either in bulk or in one metric ton bags, for export through Durban's container terminal.
Safety, health, quality and the environment
Safety and health
The safety and health of the Cato Ridge Alloys personnel is of utmost importance. The company is currently working towards becoming OHSAS 18001 certified to minimise the possibilities of occupational injuries or diseases.
Environment
Cato Ridge Alloys is located at Cato Ridge and forms part of the Assmang Manganese Division's Cato Ridge Works. The company has a high public exposure due to the location of the plant midway between Pietermaritzburg and Durban adjacent to the routes of the annual Comrades Marathon and Duzi canoe race.
The converter is equipped with filtration equipment which minimises the exposure to the atmosphere of airborne pollution generated during the charging, blowing and tapping operations, the entire operation is 'interlocked' to the filtration equipment and as such cannot operate without it.
To minimise the impact of the company on the environment, slag is recirculated to the submerged arc furnaces and the dust is sold to be utilised as pigment in the brick and ceramic industry.
Cato Ridge Alloys demonstrates commitment to the environment by being ISO 14001 certified.
Quality
Cato Ridge Alloys' commitment to its customers is demonstrated in its ISO 9002 Quality Control program. Cato Ridge Alloys obtained its ISO 9002 Quality listing in 1998.
Direct interaction with customers or agents in Europe is carried out by Ore and Metal Company Ltd and in the Americas mainly by Sumitomo Corporation.
Every employee at Cato Ridge Alloys strives towards meeting the ever-increasing demand for quality products. Quality training programmes are run on a continuing basis.
Statistical Process Control is used to ensure that the product complies with the specification while still maximising the manganese yield. Analyses are done on every ladle of hot metal supplied and every ladle of refined metal cast.
Once sized, the metal is stored on concrete storage areas in stockpiles, which are demarcated according to grade and size. All orders are checked chemically and physically before being dispatched and a certified analysis is provided.