science

Kaldo converter

Kaldo converter is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Kaldo converter rather than just read about it. In short: A Kaldo converter (using the Kaldo process or Stora-Kaldo process) is a rotary vessel oxygen based metal refining method. Originally applied to the refining of iron into steel, with most installations in the 1960s, the process is (2014) used primarily to refine non ferrous metals, typically copper.

Key takeaways

Kaldo converter belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Kaldo converter to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Kaldo converter from memory before moving on to harder problems.

Reference excerpt

A Kaldo converter (using the Kaldo process or Stora-Kaldo process) is a rotary vessel oxygen based metal refining method. Originally applied to the refining of iron into steel, with most installations in the 1960s, the process is (2014) used primarily to refine non ferrous metals, typically copper. In that field, it is often named TBRC, or Top Blown Rotary Converter.

History and description

Steel production

The name "Kaldo" is derived from Prof. Bo Kalling, and from the Domnarvets Jernverk (Stora Kopparbergs Bergslag subsidiary) both key in the development of the process. Research into the use of a stirring to promote mixing, and therefore rate of conversion was investigated from the 1940s, and investigations into the use of oxygen began c.1948. The feedstock at the Domnarvet works had a phosphorus content of 1.8-2.0% and so the process was developed with one aim being dephosphorisation. The first production unit was installed in 1954 at Domnarvet Jernverk. The converter was a top blow oxygen converter, similar to Linz-Donawitz (LD) type, using a cylindrical vessel; the vessel was tilted whilst conversion took place, with typical rotation speeds of around 30 revolutions per minute; the oxygen was injected via a lance, with slag forming materials added separately. Kaldo converters were relatively common in the 1960s in the United Kingdom, during the transition from predominately open hearth process steelmaking to oxygen based steelmaking techniques. Converters were installed at Consett steelworks, Park Gate, Rotherham, Shelton works, Stoke-on-Trent; and Stanton Iron Works. Before the advent of the basic-LD process the Kaldo method was a preferred one in the UK for converting high phosphorus iron. The first unit in the UK was at Park Gate Works, Rotherham. In the USA, the process was installed at the Sharon Steel Corporation (c.1962). A plant in Japan was installed for Sanyo Special Steel Co. (Himejii) in c.1965. A combined type of converter (LD-Kaldo), using elements of the Linz-Donawitz (LD) and Kaldo processes was installed 1965 in Belgium at Cockerill-Ougrée-Providence's plant in Marchienne-au-Pont as a multicompany research venture. In France, one Kaldo furnace was also installed (one 160t unit, 1960) at Sollac's Florange steelworks. It was followed in 1969 by two huge 240t units, the biggest Kaldo converters ever built (two times bigger than the previous bigger ones : 1000t rotating at 30 r.p.m. !), at de Wendel-Sidelor's (later Usinor-Sacilor) Gandrage-Rombas steelworks (Lorraine, France); these two converters did not meet expectations and the third additional planned Kaldo unit was not installed, instead two OLP (oxygène-lance-poudre) 240t units were used. Disadvantages of the process, compared to non-rotating oxygen furnaces (e.g. LD type) were the higher capital cost, more difficult to upscale to higher outputs, and additional complexity (i.e. rotating parts and loading thereof). Advantages included the ability to use a high proportion of scrap metal, and good controllability of final steel specification. At the Park Gate works conversion time was 90 minutes, with up to 45% scrap loading, with a capacity of 75t in a 500t total, 16 feet (4.9 m) diameter converter, with a rotation speed of 40 revs per minute. Due to high maintenance costs the Kaldo converter did not gain widespread usage in the steel industry, with non-rotating converters being preferred.

Non-ferrous production Nickel matte was converted by Inco (Canada) in a pilot Kaldo converter in 1959, and Metallo-Chimique (Belgium) developed secondary copper smelting using the Kaldo type converters in the late 1960s. The Kaldo type converted is commonly known as a Top-Blown Rotary Converter (TBRC) in non-ferrous metal smelting terminology. By the 1970s, the Kaldo furnace was in common use for copper and nickel smelting. A Kaldo converter for the smelting of lead was constructed by Boliden AB in Sweden in 1976. Kaldo secondary copper units were still in use worldwide at the beginning of the 21st century, but as of 2011 no new units had been commissioned for around 10 years, suggesting that the process had been superseded.

Illustrations

Worked examples

Example 1 — a first encounter with Kaldo converter

Start with the simplest possible case. Write down what Kaldo converter claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Kaldo converter before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Kaldo converter ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Kaldo converter

In research: Kaldo converter appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Kaldo converter in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Kaldo converter is common in secondary-school and first-year university syllabi. It links to neighbouring topics Copper processes, Smelting, Steelmaking, so understanding it makes those chapters shorter.
In everyday life: Look for Kaldo converter outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Kaldo converter in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Kaldo converter means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Kaldo converter out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Kaldo converter in simple terms?

Why does Kaldo converter matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Kaldo converter?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Kaldo converter.