This site might provide another source while waiting.
http://www.staff.hum.ku.dk/dbwagner/KoreanFe/KoreanFe.html
"I have found it necessary to question one important conclusion of the Chinese metallurgists: this concerns the process by which iron was smelted from ore in early China. A group of Chinese metallurgists, writing under the pseudonym Li Zhong (1975), have proposed a method for distinguishing artefacts made from bloomery iron from those made from fined iron. The bloomery process, which produces wrought iron directly from ore, was the only process used in the ancient West for the smelting of iron. In late Medieval times the process of producing cast iron in a blast furnace and fining this to produce wrought iron was introduced and in time replaced the bloomery process. In China actual blast furnaces and fineries have been excavated from as early as the first century B.C. (e.g. Gongxian 1962; Zhao Qingyun et al. 1985; WW 1978.2: 28ff), but these are the earliest iron-production furnaces so far known in China, and we have no direct evidence concerning what processes may have been used for iron production in China before this time.
In the fining process cast iron is heated to a pasty state (a temperature well over 1000deg.C) and stirred about with an iron rod under an oxidizing blast of air. This removes most or all of the carbon from the iron, so that the result is steel or wrought iron. The process has been used in China almost up to the present; see the descriptions of the traditional process translated in Wagner 1985: 22-25, 60-69, esp. 66. A useful textbook on most aspects of pre-industrial iron-production technology is Rostoker & Bronson 1990.
The Li Zhong group propose that microscopic examination of sl*g inclusions in wrought iron artefacts can be used to determine whether the raw material used by the smith in making the artefacts was bloomery iron or fined iron. Using this method they find that the wrought iron and steel artefacts from the Yan grave described above were all made from bloomery iron. I have argued in my forthcoming book (Wagner 1993, chapter 6, section 6.4) that the proposed method is inadequate, and that the question of whether the bloomery was ever used in ancient China remains unanswered. In renewed study of the question it will be important to consider Jerzy Piaskowski's very recent proposal (1992) of a method along similar lines.
In my own discussion of the question of bloomeries in ancient China I emphasize the great sophistication of early Chinese copper-smelting and bronze-casting techniques. Careful and highly technical consideration of these suggests that an iron technology which grew out of this bronze technology would most probably be one based on the production of cast iron in blast furnaces rather than the production of wrought iron in bloomery furnaces. Thus it is quite possible, as Joseph Needham suggested long ago (1958: 15; 1980: 520), that the bloomery was never known in China.
A question of terminology must be mentioned briefly here. The traditional Chinese word for the process I call "fining" is chao
, whose basic meaning is "stir-frying", a process in Chinese cooking which the iron-production process resembles . The word has unfortunately been translated into English in numerous different ways, e.g. "roasting", "parching", "puddling", "refining", "fining". "Fining", the word I have chosen here, is a nineteenth-century English word for a broad range of iron-production processes which work in the same general way. Readers of the available literature in English on ancient East Asian iron-production processes are hereby warned to be aware of the different terms used for the same process. Similarly they should be aware that bloomery iron is often called "sponge" iron.
Another means of producing wrought iron raw material from cast iron was used in the Han and somewhat later times. Whereas in the fining process the iron is heated so hot that it is in a pasty state and can be stirred about, it is also possible to use a lower temperature and decarburize the iron in the solid state. Cast iron from the blast furnace is cast into thin plates, typically on the order of 10 x 20 cm and 0.4 cm thick (e.g. KGXB 1978.1: 21, pl. 2.4). These are heat-treated, presumably in a kiln, in an oxidizing atmosphere, perhaps at a temperature of 750-850deg.C for a period of days. This process removes the carbon and results in wrought-iron plates which can be easily formed by the smith by either hot or cold hammering. This process was probably less fuel-efficient than fining, but may have been more labour-efficient and, perhaps most important, lent itself to large-scale production by unskilled labourers with quality control by sampling rather than piece-by-piece testing. We shall see below certain artefacts found in Korea and Japan which resemble these Chinese artefacts and may be imports from the large-scale iron industry of Han China. "