science

Hunter process

Hunter process 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 Hunter process rather than just read about it. In short: The Hunter process was the first industrial process to produce pure metallic titanium. It was invented in 1910 by Matthew A.

Key takeaways

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

Reference excerpt

The Hunter process was the first industrial process to produce pure metallic titanium. It was invented in 1910 by Matthew A. Hunter, a chemist born in New Zealand who worked in the United States. The process involves reducing titanium tetrachloride (TiCl4) with sodium (Na) in a batch reactor with an inert atmosphere at a temperature of 1,000 °C. Diluted hydrochloric acid is then used to leach the salt from the product.

TiCl4(g) + 4 Na(l) → 4 NaCl(l) + Ti(s) Prior to the Hunter process, all efforts to produce Ti metal afforded highly impure material, often titanium nitride (which resembles a metal). The Hunter process was used until 1993, when it was replaced by the more economical Kroll process, which was developed in the 1940s. In the Kroll process, TiCl4 is reduced by magnesium instead of sodium. Both methods share the same initial step, obtaining TiCl4 from ore by chlorination and carbothermic reduction of the oxygen. The Kroll process is now the most commonly used titanium smelting process. The Hunter process was conducted in either one or two steps. If a single step was used the reaction equation is as above. Because of the large amount of heat generated by the reduction using sodium compared to using magnesium, and the difficulty in controlling the vapor pressure of liquid sodium, a two step process may instead be used. The two step processes consisted of reducing TiCl4 to TiCl2 with half the stoichiometric amount of sodium required to reduce TiCl4 to Ti. Next, the TiCl2 in molten sodium chloride is transferred to a different container with the additional sodium required to form Ti. The two step processes proceeded according to the following two reactions:

TiCl4(g) + 2Na(l) → TiCl2(l, in NaCl) + 2NaCl(l) TiCl2(l, in NaCl) + 2Na(l) → Ti(s) + 2NaCl(l) The titanium produced by the Hunter process is less contaminated by iron and other elements and adheres to the reduction container walls less than in the Kroll process. The titanium produced by the Hunter process is in the form of powder called sponge fines. This form is useful as a raw material in powder metallurgy. The main limiting factor for the usefulness of the Hunter process is the difficulty of separating the produced NaCl from the titanium. The vapor pressure of NaCl produced in the Hunter process is lower than the vapor pressure of MgCl2 produced by the Kroll process. Thus it is difficult to separate the NaCl from the titanium using distillation in an efficient manner. Therefore, the NaCl is removed by leaching in an aqueous solution. Recovering the byproduct (NaCl) from this aqueous solution is a process that requires additional energy. These issues motivated the discontinuation of the Hunter process in industry in 1993. Research into sodium reduction continues to this day due to the superior form and purity of the metal deposit produced when compared with the Kroll process.

References

Worked examples

Example 1 — a first encounter with Hunter process

Start with the simplest possible case. Write down what Hunter process 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 Hunter process 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 Hunter process 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 Hunter process

In research: Hunter process 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 Hunter process 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: Hunter process is common in secondary-school and first-year university syllabi. It links to neighbouring topics Industrial processes, Titanium processes, so understanding it makes those chapters shorter.
In everyday life: Look for Hunter process 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 Hunter process in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Hunter process 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 Hunter process out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hunter process in simple terms?

The Hunter process was the first industrial process to produce pure metallic titanium. It was invented in 1910 by Matthew A.

Why does Hunter process 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 Hunter process?

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 Hunter process.