This term occurred frequently during the 27 years I was monitoring Radio Moscow at BBC Monitoring, and we had to translate it as "bulk chemistry".

If I understand the sentence in question correctly, it should be large (grand/big) scale chemical production (большая химия vs. бытовая химия) or something of this sort.
Bulk Chemistry is a term referring to the percentage of each element that makes up a particular composition or a material.

большая химия = химия технологических процессов
или возможно
Chemistry for Industrial Applications

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Note added at 2002-04-23 21:53:02 (GMT)
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Работаю в академии наук (российской). Задала этот вопрос местным учёным-химикам (нескольким). Единственное, что могу сказать с уверенностью, что сами учёные этот «термин» не употребляют и даже не понимают, т.е. в научном смысле химия не подразделяется на большую и малую. И это ни в коем случае не научный и не технический термин. Это газетный штамп, пришедший к нам из советской эпохи пятилетних планов, когда всё должно было быть «большим». «Я планов наших люблю громадьё…» отсюда и химия большая.

"Big" is often used to describe large-scale industries - Big Oil, Big Agriculture, etc., and such usage has been around for years. Example:
Edward Rossel on industrial conversion
Heavy industry enterprises of Urals were to produce weapons. Not only weapons for enemy destruction in all the spheres, but also for "fight for a harvest", for "black gold" of oil fields, for "big chemistry", for "bread of industry" (coal - ed.) ... And what is the most important thing for any weapon? Not a striking force, not an armour, not a precision. No. The main thing is uniformity, compatibility, mass-production. One tank is gone - two twins come. For many years enterprises of Urals has been cultivated in the way to produce weapons that were not to be regretted in battles: simple, reliable and uniform.

Industrial conversion is frequently shown as just making tractors instead of tanks. This is an easy way, and tractors will be as tanks: simple, reliable and uniform. But today we need definitely another machines: multi-functional and resource-saving, adjusted for the specific needs of a future user. Consumers became really specific when a new market economy gave them a chance of choice. And this is what Russian industry has to study yet. Look at the AutoVAZ (biggest Russian automobile plant - ed.). It's never produced tanks. It has the most up-to-date technology. But if you knew their product, you will agree it's a subject of conversion also. Conversion is not just knives instead of swords, not just kitchen-pots made of strategic titanium. Conversion is the struggle against pathologic uniformity, for making both technological lines and directors' brains more flexible.

We have a good example in Yekaterinburg too. The UralTransMach plant is preparing to make electric trams. "Why are those guys so slow, when would they start at last? The models had been tested in the city long ago!" - This is what citizens ask me. But there is a long road from test-models to mass production; the new plant is to be built under the old roof. This is a real conversion - a long road and a big price for the uniformity of socialism.


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Note added at 2002-04-23 13:32:18 (GMT)
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For similar examples check Big Oil, Big Agriculture in Google

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Note added at 2002-04-23 20:48:13 (GMT)
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Idiomatic or not, it is being used. E.g., September, 1999 No. 9 - Table of Contents
... Big Chemistry - Queen of Economy International Exhibition \"Chemistry
- 99\", Russia, Moscow, ZAO Expocentre, September 6-10, 1999. ...
archive.expert.ru/oborud/99/09-99/e9ogl.htm - 8k - Cached - Similar pages

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