The sensible waste-acid management solution

A complete and cost-effective waste-acid regeneration service for the South African steel manufacturing and processing industries.

Through a combination of world-class technology and proven, customer-focused services, Metsep SA saves you money, time, inconvenience and the risks associated with hazardous waste.


The complete, cost-effective waste-acid and waste water solutions


Today’s pickle plant operators in the steel manufacturing and processing fields have a complete solution to what is often considered to be their biggest problem: how best to manage their spent hydrochloric acid.

Metsep, through a series of dedicated, customer-focused services and processes, helps pickle plant operators to dispose of their waste acid simply, efficiently and cost-effectively without risking the well-being of their production personnel or the environment. Our core objective is to enable companies to manage, with optimum effectiveness, the waste acid generated from steel treatment processes. This is especially relevant for companies that have high standards for their quality and environmental management programmes.


Metsep operates either through plants dedicated to a single customer, or using a centralised acid regeneration servicing a number of localised customers.

Dedicated Acid Regeneration Plant

Metsep supplies an acid regeneration service to steel works or steel processing companies, whereby Metsep either builds or operates an acid regeneration plant designed to the customers exact requirements, or takes over and modernises an existing acid regeneration facility.

Various options exist for the customer, for example, Metsep build, own and operate the acid regeneration plant on site, or across the fence; Metsep manage, operate and maintain the acid regeneration plant with ownership residing with the steelworks; Metsep takes over or purchases an existing acid plant and thereafter modernises or builds a new facility. These out-sourcing options allow Metsep as an experienced operator to manage the acid plants enabling the steelworks resources to focus on its core business of steel manufacture.

Centralised Acid Regeneration Plant

Metsep owns and operates acid regeneration plants which provide a service to steel picklers and fabricators which either cannot economically justify an acid regeneration plant on site or do not want the problems associated with owning and operating an acid regeneration plant on a steel fabricating site.

It is standard Metsep practice to deliver a consignment of regenerated acid that is inhibited fully to customer requirement. All deliveries are timeous and to an agreed specification with an accompanying certificate of analysis.

Project Execution

In addition to its operating know how, Metsep is able to provide its clients with a range of project execution options that can be applied to either the refurbishment or modification of existing plants or the building of completely new plants. Metsep’s flexible approach to the design and construction of acid regeneration plants includes the following:

• Reimbursable project management, engineering and construction management of plans for and on behalf of clients (EPCM).

• The complete turnkey supply of acid regeneration plants (EPC) whereby Metsep assumes the full risk and responsibility for the manufacture, construction and commissioning of the plant.

• The provision of design and engineering services for the refurbishment and upgrade of existing plans.

• The design and installation of plant control and management systems specific to the needs of the client.

Metsep ensures that its extensive experience in plant operations and maintenance is employed by its project execution teams to provide optimum plant performance and reliability.

Technical Advice

Taking our customer’s commitment further, we provide a series of complimentary technical advisory and support services. For example, our technical advisory team can provide valuable information on acid-resistant materials and fittings, pickle bath construction and procurement, and plant layout and operation. Our facilities include laboratories with state-of-the-art analytical equipment to ensure all batches are analysed accurately, reliably and efficiently. All analytical data is supplied to customer’s confidentiality.

All-in-all, these services are customised to your needs to strengthen your competitive edge.

Services to large and small customers

There is a growing trend for large manufacturers such as steel works and steel processing companies to increase their focus on core products and production processes, and to outsource non-core services and operations. Metsep’s dedicated waste-acid regeneration facilities and services are ideal for manufacturers to outsource acid regeneration operations.

Metsep has access to the necessary technology and design facilities to be able to provide and operate custom built acid regeneration facilities which could be dedicated to the service of regenerated acid consumers.

In addition to acid regeneration, Metsep provides a further service to customers, in that it operates waste water effluent treatment plants. Metsep is well placed to provide this service by taking over existing plants or will own and operate new, custom, designed waste water effluent treatment plants for the customer.

As an independent company with a sound performance record, Metsep can provide the steel manufacturing and processing industries with proven economical, technological and environmental benefits.


Technological excellence worldwide


Metsep uses the internationally proven spray-roaster acid-regeneration process technology. Metsep has over 50 years’ experience in operating, maintaining and developing ARPs. The company has technology agreements with Amec-BKW (successors of Babcock International) being well placed to further develop the technology for the benefit of steel structures and processors. Dedicated hydrochloric acid recovery plants are used for economical, technological and environmental advantages to more than 200 major steelworks around the globe. The renowned spray-roaster process, applied successfully for more than 50 years, separates iron chloride and other metal chlorides from spent acid.

The Process…

When steel is pickled with hydrochloric acid a chloride solution is produced:
FeO + 2HCl = FeCl2 = H2O

In the regeneration system, the iron chloride (FeCI2) is converted into Hydrochloric acid and iron oxide by hydrolytic decomposition.
2 FeCI2 + 2H2O + 1/2O2 = Fe2O3 = 4HCl

This reaction takes place in the reactor at temperatures ranging from 600°C to 800°C.

The iron chloride containing waste pickling acid from the pickling system is conveyed to the evaporator, where it comes into direct contact with the hot waste gases from the reactor and concentrated. This concentrated iron chloride solution is sprayed into the spray roasting reactor.

At reaction temperatures between 600°C and 800°C, the iron chloride solution is converted into hydrogen chloride and iron oxide by means of water vapour and atmospheric oxygen.

Via the cyclone, the hydrogen chloride gas, water vapour and combustion gases are routed to the evaporator and on to the absorption column, where the HCI gas is absorbed adiabatically by adding rinse water from the pickling plant.

The resulting azeotropic acid (18% of weight) is recycled to the pickling process. The gas from the column is cleaned in a scrubber stage in accordance with environmental requirements and then discharged to the atmosphere.

A fan keeps the system under vacuum, preventing the HCI gas from escaping.

Iron oxide powder in the reactor is transported to the appropriate tanks and then filled into big bags.

The many strengths…

• highly economical
• closed acid loop between the pickling plant and the regeneration system
• Si-, Zn- and Pb- containing waste pickles can be treated
• rinse water can be used as absorption water in the regeneration plant, thus pickling plant can be operated without waste water
• consistently high pickling quality due to constant iron and acid concentrations
• reactors can be heated with any gaseous or liquid fuels.
• high–purity iron oxide produced

A cleaner environment

As the acid loop between the pickling plant and the regeneration system is closed, and the rinse water from the pickling plant is re-used in the regeneration system, the pickling system can be operated largely without producing waste water.

The off–gases from the HCl regeneration system consist of water vapour and the combustion gases from reactor heating. The Cl2 and dust emission values conform to legal requirements.

High value iron oxide

On account of its specific qualities, the iron oxide produced with the spray roasting process is highly valued as a raw material. There is an increasing worldwide demand for such an oxide.

In plants where silicon–kilned steel is pickled, the portion of silicic acid in the waste pickling acid can be chemically reduced by the incorporation of a pre-process treatment stage.

Major iron oxide uses:
• Production of hard and soft ferrites
• Foundry applications
• Binder materials for refractories
• Colouring pigments


The hydrochloric acid advantage

The Metsep technical team advocates the use of hydrochloric acid because it has numerous economic, technical and other advantages to steel manufacturers and processors when compared with sulphuric acid:

  • Layers of iron oxide scale are more soluble in hydrochloric acid. Suitable inhibitors eliminate the risk of overpickling.
  • Hydrochloric acid pickles steel more swiftly than sulphuric acid.
  • Hydrochloric acid produces a cleaner, smoother finished surface. This benefit occurs because of three advantages:
    1. the metal is attacked less by hydrochloric acid than sulphuric acid, resulting in greatly reduced pitting;
    2. rolled-in scale deposits are removed easily when using hydrochloric acid, whereas drastic overpickling of the rest of the part may occur when using sulphuric acid; and
    3. steel rinses better when pickled with hydrochloric acid.
  • Zinc consumption is reduced because of the pickled surface’s smoother finish. This also greatly decreases the chances of steel having to be regalvanised due to dross formation and the occurrence of voids in the zinc layer being reduced significantly.
  • Chloride salts, which may remain on the steel after rinsing, are more compatible with flux solutions than sulphates. This reduces the contamination of the flux baths, thereby providing further cost advantages.
  • In an age of increasing pro-environmental initiatives, there is the added comfort of knowing that spent hydrochloric acid can be recycled, thereby obviating any requirement for dumping hazardous or toxic wastes and posing other risks to the health of people and the environment.

Metsep at a glance

More than 50 years of world-class service

Metsep Background

Founded at Johannesburg, South Africa in 1973, Metsep’s engineering and operating staff have been involved in acid regeneration for more than 50 years.

Service Ethos

Committed to excellence in customer service, process technology and technical support, Metsep strives to add value to its customers’ business operations, thereby helping to sustain world-class manufacturing standards.

This is achieved through service options: installing and operating customised regeneration facilities in-house for steelworks; regenerating spent acid for smaller users at Metsep’s centralised regeneration facilities; or the design and installation of turnkey ARP projects.

As a signatory to the worldwide principles of Responsible Care®, Metsep is committed to sound safety, health and environmental management practices.

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