JPH0723208B2 - Method for producing WC powder using rotary furnace - Google Patents
Method for producing WC powder using rotary furnaceInfo
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- JPH0723208B2 JPH0723208B2 JP2003347A JP334790A JPH0723208B2 JP H0723208 B2 JPH0723208 B2 JP H0723208B2 JP 2003347 A JP2003347 A JP 2003347A JP 334790 A JP334790 A JP 334790A JP H0723208 B2 JPH0723208 B2 JP H0723208B2
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- powder
- furnace
- rotary
- rotary furnace
- gas
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Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は,WC粉の直接炭化法に関し，詳しくは回転炉を
用いた直接炭化法における品質の安定したWC粉の製造方
法に関する。Description: TECHNICAL FIELD The present invention relates to a direct carbonization method for WC powder, and more particularly to a method for producing WC powder with stable quality in the direct carbonization method using a rotary furnace.
［従来の技術］ 従来,W粉の炭化物の粉末を工業的規模で製造する方法に
は， （１）金属Ｗ粉末と炭素質粉末との均一混合物を黒鉛ボ
ートに充填して水素又は真空中で加熱する方法； （２）Ｗ酸化物と炭素質粉末との均一混合物を回転炉等
でN2，H2ガス中で連続して加熱する方法；の２通りの方
法がある。[Prior Art] Conventionally, a method for producing a carbide powder of W powder on an industrial scale includes (1) filling a graphite boat with a homogeneous mixture of metal W powder and carbonaceous powder, and then in hydrogen or vacuum. Method of heating; (2) Method of continuously heating a uniform mixture of W oxide and carbonaceous powder in N 2 and H 2 gas in a rotary furnace or the like;
各々の方法では，全炭素量，粒度を制御することが必要
がある。このため，（１）の方法では，配合する炭素質
粉末の量やＷの粒度，加熱温度によって制御する方法が
採用されており，他方，（２）の方法では，配合する炭
素質粉末の量や加熱温度により制御が行われている。Each method requires controlling the total carbon content and particle size. For this reason, the method of (1) employs a method of controlling the amount of carbonaceous powder to be blended, the particle size of W, and the heating temperature, while the method of (2) employs an amount of carbonaceous powder to be blended. It is controlled by the heating temperature.
［発明が解決しようとする課題］ 近年，超微粒超硬合金の生産は，増加の傾向にあり，こ
れらは高精度で高機能を有する製品として安定した品質
が要求される。[Problems to be Solved by the Invention] In recent years, the production of ultrafine-grained cemented carbide has been on the increase, and stable quality is required for these products with high accuracy and high functionality.
従って，これらの製品要求も自と厳しくなってきてお
り，原料のWC粉において全炭素量，粒度といった特性が
安定して製造出来ることが問題となっている。Therefore, the requirements for these products are becoming stricter, and it is a problem that the raw WC powder can be manufactured with stable characteristics such as total carbon content and particle size.
上述した（１）の金属タングステン粉末と炭素粉末との
均一混合物を水素又は真空中で加熱することにより,WC
粉末を得る方法においては，生成反応が発熱反応である
ため，ボート中心部で異常発熱を起こし，局部的に粒成
長が生じるので，微粒WC粉は製造することが困難であ
る。By heating the homogeneous mixture of the metallic tungsten powder and carbon powder of (1) above in hydrogen or vacuum, WC
In the method of obtaining powder, since the generation reaction is an exothermic reaction, abnormal heat generation occurs in the center of the boat, and grain growth locally occurs, so it is difficult to produce fine WC powder.
しかも，水素中では，浸炭作用を伴うため，ボートの上
下部で，結果的に残存する炭素量が異なり，品質の安定
性を欠く。Moreover, since the carburizing action is involved in hydrogen, the amount of carbon remaining in the upper and lower parts of the boat is different, and the quality is unstable.
更に，原料である微粒Ｗ粉を得るには工業的に限界があ
り，自と高付価価値の超微粒超硬合金製品使用範囲は狭
くならざるを得ない。Further, there is an industrial limit in obtaining the fine-grained W powder as a raw material, and the range of use of the ultrafine-grained cemented carbide products of high value is inevitably narrowed.
一方，上述した（２）の方法によるタングステン酸化物
と炭素質粉末との均一混合物を回転炉炭化炉で，N2，H2
ガス中で連続して加熱する直接炭化法においては，微粒
WC粉が得られるが，炉材のカーボン部材がH2及びO2等と
反応し（酸素と反応した場合はCO2に変化する。），損
耗し表面状態が変わることで，温度分布に変化をもたら
し，これにより全炭素含有量,WC粒度に経時的な変化を
もたらす。On the other hand, a homogeneous mixture of tungsten oxide and carbonaceous powder prepared by the above-mentioned method (2) was subjected to N 2 and H 2 in a rotary furnace carbonization furnace.
In the direct carbonization method of continuously heating in gas, fine particles
WC powder is obtained, but the carbon material of the furnace material reacts with H 2 and O 2 etc. (when it reacts with oxygen, it changes to CO 2 ), wears and changes the surface condition, and the temperature distribution changes. This causes changes in the total carbon content and WC grain size over time.
図２に示すように,CによるWO3の還元は，約700℃（970
K）で始まり,COとCO2が同時に発生することが標準生成
エネルギーから予想され，それより高温となるとCOが発
生することは予想される。As shown in Fig. 2, the reduction of WO 3 by C is about 700 ℃ (970
It is expected from the standard production energy that CO and CO 2 are simultaneously generated, starting at K), and CO is expected to be generated at higher temperatures.
そこで，本発明の技術的課題は，回転炉を用いた直接炭
化法において全炭素量及び粒度等の特性が安定して製造
できるWC粉の製造方法を提供することにある。Then, the technical subject of this invention is providing the manufacturing method of WC powder which can be manufactured by the direct carbonization method using a rotary furnace with stable characteristics, such as total carbon amount and particle size.
［課題を解決するための手段］ 本発明によれば，所定温度分布を有し，炉内に配され回
転することにより原料を移送しながら加熱する回転チュ
ーブを有する回転炉でWO3を直接炭化してWC粉を製造す
る方法において，前記炉内で発生するCO2のガス量を検
出し，当該検出したガス量の値に基いて，前記回転チュ
ーブの回転数を制御して，前記WC粉の炭素含有量及び粒
度を調節することを特徴とする回転炉を用いたWC粉の製
造方法が得られる。[Means for Solving the Problems] According to the present invention, WO 3 is directly carbonized in a rotary furnace having a predetermined temperature distribution and having a rotary tube arranged in the furnace to heat while transferring raw materials by rotating. In the method for producing WC powder, the amount of CO 2 gas generated in the furnace is detected, and the number of revolutions of the rotary tube is controlled based on the value of the detected gas amount. There is provided a method for producing WC powder using a rotary furnace, which is characterized by controlling the carbon content and particle size of
本発明のように，直接炭化法の反応は， 次式（ａ）に示す如く,CO以外に若干のCO2が発生する。As in the present invention, in the reaction of the direct carbonization method, as shown in the following formula (a), some CO 2 is generated in addition to CO.
WO3＋xC→WC＋yCO＋zCO2 …（ａ） （但し,x＝１＋ｙ＋ｚ） CO及びCO2の標準生成自由エネルギー，ΔＧを比較する
と，約700℃の近傍でその値が等しくなり，それによ
り，低温側では，CO2，高温側ではCOがそれぞれ安定に
なる。WO 3 + xC → WC + yCO + zCO 2 (a) (where x = 1 + y + z) Comparing the standard free energies of formation of CO and CO 2 , ΔG, the values become equal in the vicinity of about 700 ° C, so that on the low temperature side , CO 2 and CO become stable on the high temperature side.
従って，炉材の損耗度により，温度分布，滞留時間に差
が生じ，発生比率が変動し，全炭素含有量及び粒度に変
化をもたらすことがわかった。Therefore, it was found that the degree of wear of the furnace material caused differences in temperature distribution and residence time, and the generation ratio fluctuated, resulting in changes in the total carbon content and particle size.
そこで，本発明者らはガスの発生比率が一定になるよう
に（CO2）に注目し操炉条件を変化させる方法を完成し
たものである。Therefore, the present inventors have completed a method of changing the furnace operating conditions by paying attention to (CO 2 ) so that the gas generation rate becomes constant.
［作用］ 本発明において，回転炉内に配される回転チューブは，
所定温度分布を有し，回転することにより原料を移送し
ながら加熱する。[Operation] In the present invention, the rotary tube arranged in the rotary furnace is
It has a predetermined temperature distribution and rotates to rotate the raw material while heating it.
原料のWO3と,C粉とは，炉内にて反応し，直接炭化され
てWC粉となる。The raw material, WO 3 , and C powder react in the furnace and are directly carbonized into WC powder.
この際に，炉内で発生するCO2のガス量を検出し，当該
検出したガス量の値に基いて，回転チューブの回転数を
制御する。At this time, the amount of CO 2 gas generated in the furnace is detected, and the rotation speed of the rotary tube is controlled based on the detected amount of gas.
回転数を調節し制御することとにより，炉内での原料の
通過時間，即ち，加熱時間が制御され，これにより製造
されたWC粉の炭素含有量及び粒度が一定に保たれる。By adjusting and controlling the rotation speed, the passage time of the raw material in the furnace, that is, the heating time is controlled, and the carbon content and particle size of the produced WC powder are kept constant.
［実施例］ 以下に，本発明の実施例を図面を参照して説明する。Embodiments Embodiments of the present invention will be described below with reference to the drawings.
第１図は本発明の実施例に係る回転炉の制御システムを
示すブロック図である。FIG. 1 is a block diagram showing a rotary furnace control system according to an embodiment of the present invention.
第１図において，第１の回転炉１及び第２の回転炉２
が，上下２段に従い連結されている。In FIG. 1, a first rotary furnace 1 and a second rotary furnace 2 are shown.
Are connected according to the two upper and lower stages.
第１の回転炉１は，炉内に貫通して収容された黒鉛又は
炭素表面を有し，外部の断熱材が，その周囲に形成され
た回転チューブ３を有し，このチューブ３を加熱するよ
うに回転チューブ３の中心部に貫通して黒鉛発熱体から
なるヒータ４が配されている。The first rotary furnace 1 has a graphite or carbon surface which is penetrated and contained in the furnace, and an external heat insulating material has a rotary tube 3 formed around the surface, and heats this tube 3. Thus, the heater 4 made of a graphite heating element is arranged so as to penetrate through the center of the rotary tube 3.
第１の回転炉１の一端上方には，原料のWO3とＣとの混
合粉を供給するスクリュー５を内部に備えたホッパー６
が設けられている。Above one end of the first rotary furnace 1, a hopper 6 having a screw 5 for supplying a mixed powder of raw materials WO 3 and C therein is provided.
Is provided.
加熱された原料は，窒素気流中にて炉の一端に対向する
他端から第１の原料排出部７を経て，第２の回転炉２に
供給される。The heated raw material is supplied to the second rotary furnace 2 through the first raw material discharge part 7 from the other end facing the one end of the furnace in a nitrogen stream.
第２の回転炉２は，第１の回転炉１と同様な形状及び材
料の回転チューブ８と，ヒータ９とを備えている。The second rotary furnace 2 includes a rotary tube 8 having the same shape and material as the first rotary furnace 1 and a heater 9.
第２の回転炉２に供給された原料は水素気流中にて加熱
され，炭化されて排出部10から排出される。The raw material supplied to the second rotary furnace 2 is heated in a hydrogen stream, carbonized, and discharged from the discharge part 10.
次に，回転炉の制御システムについて説明する。Next, the control system of the rotary furnace will be described.
第１の回転炉１のヒータ４は，ヒータ制御部13により制
御される。回転チューブ３は，チューブ回転部12によ
り，その回転を調節される。The heater 4 of the first rotary furnace 1 is controlled by the heater controller 13. The rotation of the rotating tube 3 is adjusted by the tube rotating unit 12.
第２の回転炉２も第１の回転炉１と同様に，ヒータ９に
接続されたヒータ制御部16と，回転チューブ８を回転さ
せるチューブ回転部14とを有し，回転チューブ８の回転
は，チューブ回転部により調節される。Similarly to the first rotary furnace 1, the second rotary furnace 2 also has a heater control unit 16 connected to the heater 9 and a tube rotating unit 14 for rotating the rotary tube 8. , Adjusted by the tube rotating part.
これら，第１の回転炉１のチューブ回転部12及びヒータ
制御部13と，第２の回転炉２のチューブ回転部14及びヒ
ータ制御部16は,CPUを内蔵した制御回路17に夫々接続さ
れている。The tube rotating unit 12 and the heater control unit 13 of the first rotary furnace 1 and the tube rotating unit 14 and the heater control unit 16 of the second rotary furnace 2 are connected to a control circuit 17 containing a CPU, respectively. There is.
一方，第１の回転炉１には，炉内に発生したCO2のガス
を取り入れるガス流出管18が設けられている。On the other hand, the first rotary furnace 1 is provided with a gas outflow pipe 18 for taking in CO 2 gas generated in the furnace.
WC粉に含有される全炭素量を測定するには，炉内のCO濃
度，CO2濃度，若しくはCOとCO2の濃度比を測定すれば良
いわけであるが,COの場合は，雰囲気の大部分を占める
ために感度の良い分析計においては，その濃度変化を測
定することは難しい。To measure the total amount of carbon contained in WC powder, CO concentration in the furnace, CO 2 concentration, or the concentration ratio of CO and CO 2 should be measured. Since it occupies the most part, it is difficult to measure the concentration change in an analyzer with high sensitivity.
一方，CO2は雰囲気中の微量濃度であるので，ガスクロ
マトグラフィ，赤外線吸収等の分析計によって，その変
化の測定が容易である。このことから，CO2濃度変化を
測定することが，最も適当な方法であるといえる。On the other hand, since CO 2 has a very small concentration in the atmosphere, its change can be easily measured by an analyzer such as gas chromatography or infrared absorption. From this, it can be said that measuring the change in CO 2 concentration is the most appropriate method.
測定されるガスがCO2ガスの場合は，この流出管18はフ
ィルタ19を介してCO2ガス分析計20に至る。When the gas to be measured is CO 2 gas, this outflow pipe 18 reaches the CO 2 gas analyzer 20 via the filter 19.
CO2ガス分析計20は，CO2のガス濃度を検出し，その検出
値を記録部21に送出する。The CO 2 gas analyzer 20 detects the gas concentration of CO 2 and sends the detected value to the recording unit 21.
記録部21は，CO2ガス分析値を，この記録部21に接続し
た表示装置22で表示する。接続されている制御回路17に
送出する。The recording unit 21 displays the CO 2 gas analysis value on the display device 22 connected to the recording unit 21. It is sent to the connected control circuit 17.
一方，制御回路17は，ガス分析計からのCO2ガス分析値
を予め定められてたデータに基づいて第１の回転炉１の
チューブ回転部12及びヒータ制御部を制御するととも
に，第２の回転炉２のチューブ回転部14及びヒータ制御
部16を制御する。On the other hand, the control circuit 17 controls the tube rotating part 12 and the heater control part of the first rotary furnace 1 based on the predetermined data of the CO 2 gas analysis value from the gas analyzer, and the second The tube rotating unit 14 and the heater control unit 16 of the rotary furnace 2 are controlled.
第１及び第２の回転炉の温度及び回転数は，各チューブ
回転部12,14及びヒータ制御部13,16によりフィードバッ
ク制御され，所定の値になるまで保持される。The temperature and the number of revolutions of the first and second rotary furnaces are feedback-controlled by the tube rotating units 12 and 14 and the heater control units 13 and 16, and are held until they reach predetermined values.
本制御システムにおいては，CO2及びCOの発生比率を変
化させないで，全炭素含有量及び粒度を安定するよう
に，炭化炉の回転チューブ3,8の回転数及びヒータによ
る温度条件を変化させて品質を制御する。In this control system, the rotation conditions of the rotating tubes 3 and 8 of the carbonization furnace and the temperature condition by the heater are changed so as to stabilize the total carbon content and particle size without changing the CO 2 and CO generation ratios. Control quality.
各回転チューブ3,8の回転速度（rpm）を変化させること
で，各回転チューブの通過時間即ち，炉内の通過時間が
変化する。By changing the rotational speed (rpm) of each rotary tube 3, 8, the transit time of each rotary tube, that is, the transit time in the furnace is changed.
通過時間を変化させることで,CO,CO2ガスの発生比を変
化させて，原料中の全炭素量を任意に変動させることが
できる。温度に関しても同様な効果が得られる。By changing the passage time, the generation ratio of CO and CO 2 gas can be changed, and the total amount of carbon in the raw material can be changed arbitrarily. Similar effects can be obtained with respect to temperature.
次に，本発明の回転炉を用いたWC粉の製造方法を実施例
を用いて具体的に説明する。Next, the method for producing WC powder using the rotary furnace of the present invention will be specifically described with reference to examples.
＜実施例１＞ WO3粉と炭素粉とを均一に混合して,2φmmのペレット状
とした。第１の回転炉内のN2気流中1200℃で，次に，第
２の回転炉内のH2気流中で1500℃で炭化を行った。得ら
れたWC粉は第１表に示すような全炭素量粒度の分布及び
反応ガス中のCO2濃度を呈した。<Example 1> WO 3 powder and uniformly mixed with carbon powder, was 2φmm of pellets. Carbonization was carried out at 1200 ° C in a N 2 stream in the first rotary furnace, and then at 1500 ° C in a H 2 stream in the second rotary furnace. The obtained WC powder exhibited the distribution of total carbon content particle size and the CO 2 concentration in the reaction gas as shown in Table 1.
第１表は，炭素粉とWO3粉との配合は固定し，炭化炉の
回転チューブの回転数のみを変化させた場合のWC粉の全
炭素量粒度の経時変化が示されている。表に示すよう
に，CO2ガスは,5.2％〜5.6％の範囲で安定している。Table 1 shows the change with time in the total carbon content particle size of the WC powder when the blending ratio of the carbon powder and WO 3 powder was fixed and only the rotational speed of the rotary tube of the carbonization furnace was changed. As shown in the table, CO 2 gas is stable in the range of 5.2% to 5.6%.
＜比較例２＞ WO3と炭素粉とを均一混合して,2φmmのペレットとした
のち第１の回転炉内のN2気流中1200℃で，次に第２の炉
内のH2気流中で1500℃で炭化した。<Comparative Example 2> WO 3 and carbon powder were uniformly mixed to form pellets having a diameter of 2 mm, and the pellets were then heated in a N 2 gas stream in a first rotary furnace at 1200 ° C and then in a H 2 gas stream in a second furnace. Carbonized at 1500 ° C.
WO3と炭素粉との配合率は変化させ，炭化炉回転チュー
ブの回転数は1.0rpmに回転した時のWC粉の全炭素量，反
応ガス中のCO2ガス量，及び粒度の経時変化を第２表に
示す。表に示すように，CO2ガス量は,3.7〜5.6％の範囲
内に変化し，全炭素量及び粒度のばらつきが実施例より
も大きいことは判明した。The compounding ratio of WO 3 and carbon powder was changed, and the total carbon content of WC powder, CO 2 gas content in the reaction gas, and particle size change with time when the rotation speed of the carbonization furnace rotary tube was rotated at 1.0 rpm. It is shown in Table 2. As shown in the table, the amount of CO 2 gas changed within the range of 3.7 to 5.6%, and it was found that the variation in the total carbon amount and the particle size was larger than that in the example.
第１表の実施例および第２表の比較例の結果から，本発
明の実施例に係る回転数をCO2量が一定になるように制
御する方法は，回転数を一定にして，炭素量を制御する
方法に比べて著しく全炭素量が安定化され，粒度のバラ
ツキが小さいことが判明した。 From the results of the examples of Table 1 and the comparative example of Table 2 , the method of controlling the rotation speed according to the embodiment of the present invention so that the CO 2 amount becomes constant makes the rotation number constant and the carbon amount. It was found that the total carbon content was significantly stabilized and the variation in particle size was small compared to the method of controlling.
［発明の効果］ 以上説明したように，本発明によれば，回転炉による直
接炭化法でCO2ガス分析を行いながら操炉を制御する方
法によって，超微粒超硬合金の原料として用いられる超
微粒WC粉末を安定した品質で供給することができる。[Effects of the Invention] As described above, according to the present invention, a method of controlling a furnace while performing CO 2 gas analysis by a direct carbonization method using a rotary furnace is used as a raw material for ultrafine cemented carbide. Fine WC powder can be supplied with stable quality.
第１図は本発明の実施例に係る回転炉による直接炭化法
の制御装置を模式的に示す図である。第２図はWO3,CO,
及びCO2の温度と標準生成自由エネルギーとの関係を示
す図である。 図中,1……第１の回転炉,2……第２の回転炉,3……第１
の回転チューブ,4……ヒータ,5……スクリュー,6……ホ
ッパー,7……原料排出部,8……第２の回転チューブ,9…
…ヒータ,10……原料排出部,12……第１のチューブ回転
部,13……第１のヒータ制御部,14……第２のチューブ回
転部,16……第２のヒータ制御部,17……制御回路,18…
…流出管,19……フィルタ,20……ガス分析計,21……記
録部,22……表示装置。FIG. 1 is a diagram schematically showing a controller for a direct carbonization method using a rotary furnace according to an embodiment of the present invention. Figure 2 shows WO 3 , CO,
FIG. 3 is a diagram showing the relationship between the temperature of CO 2 and CO 2 and standard free energy of formation. In the figure, 1 ... first rotary furnace, 2 ... second rotary furnace, 3 ... first
Rotating tube, 4 …… Heater, 5 …… Screw, 6 …… Hopper, 7 …… Raw material discharge part, 8 …… Second rotating tube, 9…
… Heater, 10 …… Material discharge part, 12 …… First tube rotating part, 13 …… First heater control part, 14 …… Second tube rotating part, 16 …… Second heater control part, 17 ... Control circuit, 18 ...
Outflow pipe, 19 ... Filter, 20 ... Gas analyzer, 21 ... Recording unit, 22 ... Display device.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 丸山 正男 兵庫県伊丹市昆陽北１丁目１番１号 住友 電気工業株式会社伊丹製作所内 (72)発明者 森 茂芳 兵庫県伊丹市昆陽北１丁目１番１号 住友 電気工業株式会社伊丹製作所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masao Maruyama 1-1-1 Kunyokita, Itami City, Hyogo Prefecture Sumitomo Electric Industries, Ltd. Itami Works (72) Inventor Shigeyoshi Mori 1-1 Kunyokita, Itami City, Hyogo Prefecture No. 1 Itami Works, Sumitomo Electric Industries, Ltd.
Claims (1)
ることにより原料を移送しながら加熱する回転チューブ
を有する回転炉でWO3を直接炭化してWC粉を製造する方
法において，前記炉内で発生するCO2のガス量を検出
し，当該検出したガス量の値に基づいて，前記回転チュ
ーブの回転数を制御して，前記WC粉の炭素含有量及び粒
度を調節することを特徴とする回転炉を用いたWC粉の製
造方法。1. A method for producing WC powder by directly carbonizing WO 3 in a rotary furnace having a predetermined temperature distribution and having a rotary tube arranged in the furnace to heat while transferring a raw material by rotating. Detecting the amount of CO 2 gas generated in the furnace, controlling the rotation speed of the rotating tube based on the value of the detected amount of gas, and adjusting the carbon content and particle size of the WC powder. A method for producing WC powder using a rotary furnace.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003347A JPH0723208B2 (en) | 1990-01-12 | 1990-01-12 | Method for producing WC powder using rotary furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003347A JPH0723208B2 (en) | 1990-01-12 | 1990-01-12 | Method for producing WC powder using rotary furnace |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03252306A JPH03252306A (en) | 1991-11-11 |
| JPH0723208B2 true JPH0723208B2 (en) | 1995-03-15 |
Family
ID=11554825
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2003347A Expired - Lifetime JPH0723208B2 (en) | 1990-01-12 | 1990-01-12 | Method for producing WC powder using rotary furnace |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0723208B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT3064U1 (en) * | 1998-12-28 | 1999-09-27 | Plansee Tizit Gmbh | GAS CARBURETOR METHOD FOR PRODUCING PURE WC POWDER |
| AT410939B (en) * | 2000-12-20 | 2003-08-25 | Treibacher Ind Ag | METHOD FOR THE PRODUCTION OF TUNGSTEN CARBIDE |
| JP5108547B2 (en) * | 2008-02-06 | 2012-12-26 | 住友重機械工業株式会社 | Combustion device and method of operating combustion device |
-
1990
- 1990-01-12 JP JP2003347A patent/JPH0723208B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03252306A (en) | 1991-11-11 |
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