1231805 (1) 玖、發明說明 【發明所屬之技術領域】 本發明係關於自含有稀土類元素之廢液回收稀土類氧 化物之方法，尤其係自含有稀土類元素之硏磨廢液，得再 利用爲高精度硏磨加工用之硏磨材回收高品質之稀土類氧 化物之方法。 【先前技術】 近年，含有稀土類元素之硏磨材被用於各種領域。尤 以鈽系之硏磨材多用於玻璃材料或水晶之硏磨。例如用於 光碟或磁碟用玻璃基板、薄膜電晶體（TFT )型液晶顯示 器（LCD )或扭轉向列型（TN )液晶顯示器（LCD )等液 晶顯示器用玻璃基板、液晶電視（TV )用彩色濾器、電 視用等陰極射線管（CRT )、眼鏡鏡片、光學鏡片、大規 模集成（LSI )光罩用玻璃基板、嵌網平板玻璃、水晶振 動器用基板等之硏磨。 在此稱之含有稀土類元素之硏磨材，係指含有铈 (Ce )、鑭（La )、鐯（Pr )、鈸（Nd )等稀土類元素 氧化物之微粉未之硏磨材。 爲含有稀土類元素硏磨材原料之礦石，如氟碳铈礦或 磷鈽鑭礦產於中國、美國等。 自氟碳鈽礦或磷鈽鑭礦等礦石製造稀土類氧化物，通 常依序施以下列1 )〜9 )之處理。 1)於旋轉窖爐中，於礦石慢慢地加入硫酸以混和、乾燥。 -5- (2) 1231805 2 )加溫至5 0 0 °C〜6 0 0 t焙燒。 3) 將焙燒礦用水瀝濾，使稀土類含有物溶解析出於水。 4) 用增稠器濃縮，濾出BaS04、CaS04、S102等雜質，得 到R 2 ( S Ο 4 ) 3。式中之R係稀土類元素。 5) 於R2 ( S04 ) 3加入硫酸鈉以分離鐵、鈣、磷酸等、得 到稀土類元素之硫酸複鹽。 6) 於稀土類元素之硫酸複鹽加入氫氫化鈉，以析出稀土類 元素之氫氧化物。 7) 於稀土類元素之氫氧化物加入鹽酸爲稀土類元素之氯化 物。 8) 於稀土類元素之氯化物加入碳酸氫銨成稀土類碳酸鹽。 9) 燒焙稀土類碳酸鹽成稀土類氧化物。 但含有稀土類元素之硏磨材原料之礦石的蘊藏量有 限’又最近隨著含有稀土類元素之硏磨材料之需求增大， 其問題爲原料之礦石不足。因此，期望自含有稀土類元素 之硏磨廢液，用以再利用爲硏磨材料回收高稀土類氧化 物。 且以稀土類氧化物微粉未爲主體之硏磨材料的使用領 域’對加工物高精度化之要求提高，該硏磨材料應具備之 品質，高度要求降低粗大粒子及降低異物。但自含有稀土 _元素之硏磨廢液，得再利用爲高精度硏磨加工用之硏磨 材料回收高稀土類氧化物實有困難。 尤以多含鈽之鈽系稀土類氧化物，係將與水、分散 劑、表面活性劑等混合成漿料化之調製物用於玻璃或水晶 -6- (3) 1231805 等之硏磨。其因爲含有稀土類元素之硏磨廢液，至少含有 硏磨材、水、分散劑、表面活性劑、玻璃等之硏磨屑、硏 磨墊屑等。且含有稀土類元素之硏磨廢液，與含有稀土類 元素之礦石較之，稀土類元素之含量，各自稀土類元素之 含有比率，稀土類元素以外之含有物，此類含有物之含有 比率等多有差異。爲此，自含有姉以外之稀土類元素之硏 磨廢液，回收得再利用爲硏磨材料之高品質的高稀土類氧 化物，其處理成本極高不實用。 自使用含有稀土類元素之硏磨材料硏磨時副產之硏磨 廢液回收含有稀土類氧化物微粉未之硏磨材料的方法，已 有許多建議。如將鹼洗硏磨廢液後，篩分塵埃等雜質與硏 磨材料之方法（如參照特許文獻1 )，用硫酸溶解硏磨廢 液後成草酸鹽，之後用鹼中和成稀土類氧化物之回收方法 (如參照特許文獻2 )，用氫氟酸溶解硏磨廢液中之玻璃 屑回收稀土類元素之方法（如參照特許文獻3 )，將硏磨 廢液凝結處理後，固液分離以回收稀土類元素之方法（如 參照特許文獻4 )等建議。 [特許文獻1] 特開平1 1 -9082 5 8號公報（第2-5頁） [特許文獻2] 特開2000-87 1 54號公報（第3-5頁） [特許文獻3] 特開平1 1 -3 1 97 5 5號公報（第2-3頁、第1圖） (4) 1231805 特開平1 0-2 8 0 06 0號公報（第3-5頁） 但，以往所建議之稀土類氧化物之回收方法，去除 異物不足，無法得到有助於工業性得再利用爲高精度硏磨 加工用之硏磨材料之高品質的稀土類氧化物。 【發明內容】 〔本發明所欲解決之課題〕 有鑑於上述狀況，本發明之目的係提供可自含有稀土 類元素之液，可將高品質之稀土類氧化物以高效率且完全 高純度回收之方法，尤自含有稀土類元素之廢液回收有助 於工業性得再利用爲高精度硏磨加工用之硏磨材料之高品 質的稀土類氧化物。 〔用以解決課題之手段〕 本發明者們，發現經由組合特定之精製方法（如 (1 )將含有稀土類元素之液與酸混合及加熱以溶解液中 之稀土類元素，（2)自（1)所得之稀土類元素之溶液去 除未溶解物，（3 )於（2 )所得之稀土類元素之溶液加入 可溶性之碳酸鹽或碳酸氫鹽或草酸之該溶液中之稀土類元 素成碳酸稀土或草酸稀土， （4)自（3)所得含碳酸稀土 或草酸稀土之漿料分離碳酸稀土或草酸稀土， （ 5 )燒焙 經分離之碳酸稀土或草酸稀土成稀土類氧化物，再（6) 回收所產生之稀土類氧化物。），自含有稀土類元素之硏 磨廢液，將得再利用爲高精度硏磨加工用之稀土類氧化物 -8- (5) 1231805 之高品質之稀土類氧化物得回收有利於工業性，基於此知 識以至完成本發明。 I根據本:發明係提供下述稀土類氧化物之回收方法， 硏磨材料之製造方法及再利用方法並硏磨方法。 1. 一種自含有稀土類元素之液回收稀土類氧化物之方 法’其特徵爲包含以下步驟（1 )〜（6 )步驟； (1 )將含有稀土類元素之液與酸混合及加熱以溶解 液中之稀土類元素， (2 )自步驟（1 )所得之稀土類元素之溶液去除未溶 解物， (3 )於步驟（2 )所得之稀土類元素之溶液加入可溶 性之碳酸鹽或碳酸氫鹽或草酸之該溶液中之稀土類元素成 碳酸稀土或草酸稀土， (4)自步驟（3)所得含碳酸稀土或草酸稀土之漿料 分離碳酸稀土或草酸稀土， (5 )燒焙經分離之碳酸稀土或草酸稀土成稀土類氧 化物，再 (6 )回收所產生之稀土類氧化物。 2. 如第1項之方法，其中步驟（1 )係將含有稀土類 元素之液與酸與過氧化氫混合及加熱以溶解廢液中之稀土 類元素之步驟。 3. 如第1或第2項之方法，其中於步驟（1 )之酸係 鹽酸。 4. 如第1或第2項之方法，其中於步驟（1 )之酸係 -9 - (6) 1231805 硝酸。 5. 如第1至4項中任一項之方法，其中步驟（1 )係 將混合酸所得之混合液回流下加熱再濃縮，使該混合液所 含之未溶解固體浮起於液面。 6. 如第5項之方法，係產生氣泡同時進行濃縮。 7. 如第6項之方法，係於防沸石下存在下加熱混合液 使其產生氣泡。 8. 如第1項之方法，其中於步驟（2 )係經由過濾去 除未溶解物。 9. 如第1項之方法，其中於步驟（3 )係將稀土類元 素溶液之pH値調整爲1〜7後，於該液加可溶性之碳酸 鹽或碳酸氫鹽或草酸之該溶液中稀土類元素成碳酸稀土或 草酸稀土。 1 0 ·如第9項之方法，其中於步驟（3 )係用氨將pH 値調整爲1〜7。 1 1 ·如第1或第9項之方法，其中於步驟（3 )之可溶 性之碳酸鹽或碳酸氫鹽，係鹼金屬鹽、鹼土類金屬鹽或銨 鹽。 12·如第1項之方法，其中於步驟（4)碳酸稀土或草 酸稀土經由濾過分離。 1 3 · —種自含有稀土類元素之液回收稀土類氧化物之 方法’其特徵爲包含以下步驟（i )〜（vi)步驟； (i )將含有稀土類元素之液與硫酸混合及加熱以溶 解液中之稀土類元素爲硫酸稀土， -10- (7) 1231805 (ii )將該硫酸稀土與水混合溶解硫酸稀土’ (Hi)自所得之硫酸稀土溶液去除未溶解物’ (iv )於所得之溶液加硫酸鈉形成稀土類元素之複 鹽，再將複鹽自溶液分離， (v )將該複鹽懸浮於水，PH値爲8〜1 3之稀土類元 素之複鹽成氫氧化稀土，再 (vi)分離氫氧化稀土，回收。 14·如第13項之方法，其中於步驟（iii )係經由濾過 去除未溶解物。 1 5 ·如第1 3項之方法，其中於步驟（v )係經由加入 鹼、氨水或氨氣，將懸浮液之pH値爲8〜1 3。 1 6 ·如申請專利範圍第1 3項之方法，其中於步驟 (i )係於含有稀土類元素之液，加硫酸鋁、多氯化鋁或 高分子凝結劑以沉澱含有稀土類元素之固體成分，分離回 收該沉澱物，再於回收物加入硫酸。 1 7 _如第1 3或1 6項之方法，其中步驟（i )係於含有 稀土類元素之液混合硫酸後，再加入過氧化氫水。 18·—種回收稀土類氧化物之方法，其特徵爲自含有 稀土類元素之液使用第1 3〜1 7項中任一項之方法回收氫 氧化稀土，將此燒焙。 19.一種回收稀土類氧化物之方法，其特徵爲自含有 稀土類元素之液使用第1 3〜1 7項中任一項之方法回收氫 氧化稀土，將此懸浮於水，自此懸浮液使用如第1〜1 2中 任一項之方法。 -11 - (8) 1231805 20.如第1〜19項中任一項之方法，其中含有稀土類 元素之液係硏磨硏磨材產生之廢液。 2 1 · —種使用稀土類氧化物之硏磨材之製造方法，其 特徵爲包含利用第1〜2 0項中任一項之方法回收者。 22·—種硏磨材之再利用方法，其特徵爲自硏磨硏磨 材產生之廢液使用第1〜2 0項中任一項之方法回收稀土類 氧化物，包含得到硏磨材者。 23 · —種硏磨方法，其特徵爲自硏磨硏磨材產生之廢 液使用第1〜2 0項中任一項之方法回收稀土類氧化物，使 用所得之硏磨材再硏磨者。 〔實施發明之形態〕 以下根據本發明以例示再加上步驟說明自含有稀土類 元素之硏磨廢液回收高品質之稀土類氧化物之方法。 又，本發明之回收方法，通常係自含有複數種稀土類 元素之硏磨廢液回收複數種之稀土類氧化物。但亦得自含 有極高相對比率之特定的稀土類元素（如鈽）之硏磨廢液 回收含有極高相對比率之該稀土類元素之稀土類氧化物， 啓始原料及所得氧化物，各自所含之稀土類元素之組成並 無特別限定。 步驟（1 )(溶解廢液中之稀土類元素，得到稀土溶液步 驟） 首先，將含有稀土類元素之硏磨廢液貯存於反應容 -12- (9) 1231805 器’於此硏磨廢液加入酸或加入酸與過氧化氫，加熱。 在此所用之酸，可爲可溶解所含稀土類元素之酸，以 自鹽酸、硝酸及硫酸中選擇爲宜。較佳爲鹽酸及硝酸，最 佳爲鹽酸。 加熱係至少可完全溶解廢液中之稀土類元素（通常爲 氧化稀土之形態）進行加熱。如使用之酸爲鹽酸時，加熱 溫度以90°C〜120 °C爲宜。較佳爲於90 °C〜120 °C之 範圍內同時攪拌5小時〜72小時，回流下加熱再濃縮。 於硏磨廢液添加鹽酸之濃度不拘，一般爲15〜45質 量％，以20〜35質量％者爲宜，可使用濃度35質量％之 濃鹽酸。鹽酸之添加量以對硏磨廢液中固體成分1 00質量 部換算35質量％之200〜5 0 0質量部之範圍爲宜。 於硏磨廢液添加硝酸之濃度亦不拘，一般以使用62 〜9 8質量％者爲宜。硝酸之添加量以對硏磨廢液中固體成 分1〇〇質量部之112〜177質量部之範圍爲宜。 若添加硝酸或硫酸等無還原性之酸時，抑制稀土類之 氧化，儘量降低產生之硝酸稀土或硫酸稀土之酸値，爲改 善其溶解性倂用具有過氧化氫等還原性之物質爲宜。經由 倂用過氧化氫等，亦可得分解去除存在於硏磨廢液中之有 機物之效果。過氧化氫之使用量以對硝酸1 〇〇質量部之9 〜2 7質量部之範圍爲宜。若添加鹽酸時，用以分解有機 物時，依所期可倂用過氧化氫。 將酸或加入酸與過氧化氫加熱，稀土類之氧化物被溶 解，如可得含有氯化稀土或硝酸稀土等稀土類元素之酸性 -13- (10) 1231805 水溶液。此時硏磨廢液中所含玻璃磨損粉成爲矽溶膠，其 後進展成凝膠化，最後成爲矽膠。 在此，此矽膠、硏磨墊屑等未溶解物，可原樣過濾分 離，但爲包入稀土類元素之酸性水溶性，用以高效率回收 稀土類元素之酸性水溶液，進行以下說明之濃縮爲宜。 若再將該稀土類元素之酸性水溶液加熱，濃縮，該酸 性水溶液之比重（濃度）提高，因而此水溶液中所含之矽 膠相對地變輕，與未溶解物同時浮起於液面上，易於以下 步驟（2 )之該酸性水溶液之分離。 若再將該稀土類元素之酸性水溶液加熱濃縮，因液面 降低，浮起於此液面上之矽膠及未溶解物，黏著於反應容 器之內壁。矽膠及未溶解物多於反應容器內壁之面積時， 可於反應容器內部設置用以擴大內壁面積之隔板等。已黏 著固定之矽膠及未溶解物若再加溫，該體積收縮，排出包 入矽膠與未溶解物之稀土類元素之酸性水溶液。爲此，內 壁及隔板等之溫度爲易引起體積收縮以保持液溫以上爲 宜，約40〜60%最佳。經由加熱濃縮，進行矽膠及未溶解 物與稀土類元素之酸性水溶液之分離，以提高其下步驟 (2 )之稀土類元素之酸性水溶液之回收率。 濃縮稀土類元素之酸性水溶液時，產生氣泡同時濃縮 爲宜。較佳爲產生細微且均勻之氣泡。若將防沸石浸没於 此水溶液，經由加熱以防沸石爲起點產生許多氣泡，同時 使產生之氣泡細微且均勻。矽膠及未溶解物與此氣泡同時 浮起於液面上。爲此，可促進於步驟（2 )之矽膠及未溶 -14- (11) 1231805 解物與稀土類元素之酸性水溶液之分離。 又，使用防沸石，得選擇不溶解於此熱溶解之玻璃等 之陶瓷、或塑膠等，具有爲氣泡起點之許多突起部分之形 狀物爲宜。 步驟（2 )(稀土類元素之酸性水溶液之分離步驟） 再自反應容器選出稀土類元素之酸性水溶液，以分離 去除殘留於液中之矽膠及硏磨墊屑等之未溶解物。分離去 除之方法無特別限定，得適用過濾或離心分離等。以操作 簡易之過濾爲宜。且去除未溶解物取出稀土類元素之酸性 水溶液。 步驟（3)(自稀土類元素之溶液產生碳酸稀土或草酸稀 土之步驟） 接著，於稀土類元素之酸性水溶液加入可溶性之碳酸 鹽或碳酸氫鹽或草酸，將該溶液中之稀土類元素成碳酸稀 土或草酸稀土。 可溶性之碳酸鹽或碳酸氫鹽，可爲步驟（3 )溶液 (酸性溶液）之可溶性鹽。以鹼金屬鹽、鹼土類金屬鹽或 銨鹽爲宜。鹼金屬鹽係用鈉、鉀、鋰等，以鈉及鉀爲宜。 鹼土類金屬鹽係用鈣、緦、鋇等。鹼金屬鹽、鹼土類金屬 鹽及銨之碳酸鹽及碳酸氫鹽中，以碳酸氫化鈉及碳酸氫化 鉀爲宜。最佳爲碳酸氫銨。 依所期預先加入此類碳酸鹽、碳酸氫鹽或草酸，以抑 -15- (12) 1231805 制粒徑爲目的，得以水稀釋稀土類元素之酸性水溶液。通 常愈稀釋所得粒子之粒子變大。 又，將稀土類元素之酸性水溶液之PH値調整爲1〜 7，較佳爲1〜3後，加入碳酸氫銨或草酸爲宜。P Η値之 調整得經由加入氨水、氫氧化鈉、氫氧化鉀、氫氧化鈣等 鹼成分進行，以使用易去除鹼成分之氨水爲宜。若使用氨 水其濃度並無特別限定通常於5〜28質量％之範圍選擇。 鹼金屬、鹼土類金屬及銨之碳酸鹽及碳酸氫鹽得以固 體或水溶液之形態加入，但以水溶液形態爲宜。此類碳酸 鹽及碳酸氫鹽之水溶液及草酸之濃度並無特別限定，得於 5質量％〜97質量％之範圍適當選定。 鹼金屬、鹼土類金屬及銨之碳酸鹽及碳酸氫鹽及草酸 之添加量，以對稀土類元素1〇〇質量部之193〜5 40質量 部之範圍爲宜。 經由加入該碳酸鹽或碳酸氫鹽、草酸，含有稀土類元 素之酸性水溶液，成爲含有碳酸稀土或草酸稀土之漿料。 步驟（4)(分離碳酸稀土或草酸稀土之步驟） 再將含有碳酸稀土或草酸稀土之漿料，經由如過濾分 離碳酸稀土或草酸稀土。依所期經分離之碳酸稀土或草酸 稀土水洗再次過濾。 步驟（5 )(碳酸稀土或草酸稀土之燒焙步驟） 再燒焙經分離之碳酸稀土或草酸稀土成稀土類氧化 -16- (13) 1231805 物。燒焙係將碳酸稀土或草酸稀土於大氣中6 0 0〜1 2 0 0 。(：，於8 0 〇〜1 1 〇 〇 °C爲宜進行0 · 5〜3小時左右，以〇 · 5 〜2小時左右爲宜。 燒焙裝置得使用箱型爐、旋轉爐、風道爐等，通常使 用燒焙爐。 步驟（6 )(稀土類氧化物之回收步驟） 燒焙所得之稀土類氧化物回收，調整粉碎之粒度（粒 徑及其分布），再利用爲精密硏磨用之硏磨材料。一般可 同於原來的硏磨材料粒子之粒徑，亦可改變。如平均粒徑 得於0.1〜2 μ m之範圍。 根據該稀土類氧化物之回收方法，可得可再利用爲精 密硏磨用之硏磨材料之高品質之稀土類氧化物，在步驟 (1 )進行含以下步驟（i )〜（iv )之前處理，再將所得 含有氫氧化稀土漿料作爲含有步驟（1)之稀土類元素之 用’經由進行步驟（1 )〜（6 )，可得較高純度之高品質 稀土類氧化物。 (i )將含有稀土類元素之液與硫酸混合及加熱將液 中之稀土類元素成硫酸稀土， (Π )將含該硫酸稀土之液與水混合以溶解硫酸稀 土， ()自所得之硫酸稀土溶液去除未溶解物， (iv )於所得溶液加入硫酸鈉形成稀土類元素之複 鹽，再分離複鹽， -17- (14) 1231805 (v )將該複鹽懸浮於水，將pH値爲8〜1 3之稀土 類元素之複鹽成氫氧化稀土，再 (vi)分離氫氧化稀土，回收。 以下說明含該步驟（i )〜（vi )之前處理。 步驟（i )(將廢液中之稀土類成硫酸稀土之步驟） 於含有稀土類元素之硏磨廢液加入硫酸加熱。 硫酸之濃度並無特別限定，如使用濃度95質量％〜 9 9質量％之濃硫酸。硫酸的量，以加入對硏磨廢液中之固 體成分1〇〇質量部之80質量部〜450質量部爲宜。 加熱係以90 °C〜120 °C加熱1〇分〜1小時。 於加入硫酸之液加入過氧化氫，可去除有機物成分如 將硏磨墊分解之單體碳爲碳氣。添加過氧化氫後，將該液 以200 °C〜600 °C再加熱1分〜1小時，將液中之稀土 類元素成硫酸稀土。用傾析或過濾等方法分離硫酸稀土爲 宜。 步驟（i i )(於硫酸稀土加水以溶解硫酸稀土之步驟） 再於經分離之硫酸稀土或硫酸稀土含有液加水，溶解 或稀釋硫酸稀土。藉此於下一過濾步驟（i i i )得高效率去 除玻璃屑或硏磨墊屑。 溶解或稀釋所用之水量，以對硫酸稀土固體成分1 〇〇 質量部之5 25質量部〜1 900質量部之範圍選擇。 (15) 1231805 步驟（iii )(自經稀釋之硫酸稀土溶液去除未溶解物之步 驟） 將經稀釋之硫酸稀土溶液利用過濾等方法，去除玻璃 屑或硏磨墊屑等。 步驟（iv )(於爐液加入硫酸鈉形成稀土類元素之複鹽之 步驟） 過濾經稀釋之硫酸稀土溶液後’於濾液加入硫酸鈉形 成稀土類元素之複鹽。 硫酸鈉以固體狀態原樣或水溶液加入。即將濃度5質 量％〜100質量％之硫酸鈉或其水溶液加入1.25〜95質量 部，以加入12.5〜80質量部爲宜’可得稀土類元素之複 鹽如 R2(S04) 3.Na2S04.2H20(R係稀土類元素）之漿 料。經由過濾漿料等方法附加分離操作’分離去除溶 '液得 到複鹽。 步驟（v)(複鹽加入鹼之稀土類元素之複鹽成氫氧化稀 土之步驟） 將於前步驟（iv )所得之複鹽加水’將pH値爲8〜 13之稀土類元素之複鹽成氫氧化稀土。pH調整以加入 鹼、氨水或氨氣將PH値爲8〜1 3爲宜。較佳爲1 2〜1 3 ° 將pH値調整爲此範圍內，可改善以下步驟之溶解性’改 善稀土類元素之回收率。 鹼以使用氫氧化鈉、氫氧化鉀等。鹼以固體形態原樣 -19- (16) 1231805 或水溶液加入。通常，將濃度1 〇〜9 5質量％之鹼水溶液 對複鹽100質量部之溶液加入33〜3 22質量部。氨水或氨 氣之添加量以氨（NH3)換算，一般爲3〜30質量部之範 圍。 步驟（vi)(回收氫氧化稀土之步驟） 將含有稀土類元素之液，如過濾回收氫氧化稀土之沉 源。此回收氫氧化稀土懸濁於水，以供步驟（1 )以下之 處理步驟。 又變更態樣，將於步驟（W)經回收之氫氧化稀土不 供步驟（1 )以下之處理步驟，得將於大氣中以600 °C〜 1 4 0 0 °C燒焙之氫氧化稀土成氧化稀土類。經由此變更態 樣所得之稀土類元素可再利用爲硏磨材，但若與經步驟 (1 )〜步驟（6 )所得之氧化稀土類較之，其品質稍差。 又，於本發明之步驟（i )，加入硫酸之前，於含有 稀土類元素之廢液，加入硫酸鋁、多氯化鋁或高分子凝結 劑使含有稀土類元素之固體成分沉澱，得進行分離回收該 沉澱物之預處理。預處理後於回收物加入硫酸。 硫酸鋁及多氯化鋁可爲固體或水溶液（通常爲濃度 1 0質量％以上）。得用於本發明之高分子凝結劑得例示如 Kuflock (栗田工業（股）製）、Orflock ( Organo (股） 製）等市售品。 經上述步驟（1 )〜步驟（6 )被回收之稀土類氧化 物，整理粉碎之粒度（粒徑及其分布）後，得再利用爲精 -20- (17) 1231805 密硏用硏磨材。該硏磨材之利用同於自當初之原礦石製造 由铈（Ce )、鑭（La )、鐯（Pr )、钕（Nd )等稀土類 元素氧化物之微粉未之硏磨材。 硏磨材之利用領域，如光碟或磁碟用之玻璃基板、薄 膜電晶體（TFT )型液晶顯示器（LCD )或扭轉向列 (TN )型液晶顯示器（LCD )等液晶顯示器用玻璃基板、 液晶電視（TV )用彩色濾器、電視用等陰極射線管 (CRT )、眼鏡鏡片、光學鏡片、LSI光罩用玻璃基板、 嵌網平板玻璃、水晶振動器用基板等之硏磨。 【實施方式】 〔實施例〕 以下根據實施例具體說明本發明，但本發明非限定於 此。 實施例1 (自硏磨廢液回收稀土類氧化物） 經由玻璃碟硏磨產生之硏磨廢液爲自表1所示之固體 成分組成之硏磨廢液回收稀土類。 於硏磨廢液1升添加濃度2 0質量％之硫酸鋁3 8 g與 高分子凝結劑（Kuflock ;栗田工業（股）製）〇.2g，混 合之固體成分使其凝結沉澱以分離回收。 將回收之固體成分100g放入已加入濃度95質量％之 濃硫酸2 6 2 g之燒杯，攪拌5分鐘。將燒杯以1 〇 〇 °C加 熱，以熱硫酸之脫水作用分解有機物呈黑色之液狀。再將 -21 - (18) 1231805 過氧化氫水滴液20g之單體碳成碳酸氣體去除。經此處理 可去除於含稀土類元素之硏磨廢液所含之有機物。 將燒杯再以3 0 0 °C加熱成黃色固體物之硫酸稀土。 將此硫酸稀土於5 °C冷水溶解成褐色透明之硫酸酸性 水溶液。 過濾此硫酸稀土之硫酸酸性水溶液’去除玻璃屑等未溶 解物。經此處理，未溶解物除玻璃以外，碳化物等亦去 除。 濾液加入濃度10質量％之Na2S〇4水溶液413g攪拌 產生複鹽。 過濾回收此複鹽後，加入純水1 500g成漿料化後，添 加濃度2 0質量％之氫氧化鈉水溶液8 5 1 g，攪拌成鹼性之 氫氧化稀土漿料。過濾此氫氧化稀土漿料，回收氫氧化稀 土固體物約1 1 〇g。此處理時之pH値係1 1 .7。 將回收之固體物與純水1 5 00g混合成漿料化後，以 95 t加熱，溶解加入濃度35質量％之鹽酸182g之固體 物成氯化稀土水溶液。此時之氯化稀土水溶液係黃色透明 液或綠色透明液。 過濾此氯化稀土水溶液去除未溶解物。 •於濾液氯化稀土水溶液添加濃度1 0質量％之碳酸氫 銨水溶液1 6 5 3 g攪拌，得到碳酸稀土之白色沉澱。 將過濾此沉澱物，洗淨得到之固體物放入磁製容器， 以1 000 °C燒焙1小時得到氧化稀土類93 g。 爲氧化稀土類所得之回收物之組成示於表1。 -22- (19) 1231805 實施例2 (自硏磨廢液回收稀土類氧化物） 經由玻璃過濾器之硏磨產生之硏磨廢液爲自表1所示 之固體成分組成之硏磨廢液回收稀土類。 於加入濃度98質量％之硫酸245g之不鏽鋼（SUS) 燒杯，加入1 〇 0 g回收粉，用不鏽鋼刮勺攪拌’用表面玻 璃覆蓋。將此燒杯置於加熱器上，以600W加熱30分鐘 後放置冷卻。 將所得之黃色固體物移至硏鉢，用杵破碎。於冰水包 圍的燒杯加入1升的冷水攪拌，此冷水慢慢地加入該破碎 物混合成硫酸稀土之硫酸酸性水溶液（褐色透明液）。 用濾紙（No. 5 C、東洋濾紙（股））過濾此硫酸稀土 之硫酸酸性水溶液，回收濾液。 於濾液添加濃度15質量％之硫酸鈉水溶液276g攪 拌。再添加濃度20質量％之氫氧化鈉水溶液約76 9g攪 拌，pH値爲6以產生複鹽。 用濾紙（N〇.5C、東洋濾紙（股））過濾此複鹽，回 收固體成分約2 1 7g於燒杯。於回收之固體成分加水攪拌 成約1 . 5升之漿料。再於此漿料添加濃度2 0質量％之氫氧 化鈉水溶液攪拌，pH値爲1 2成氫氧化稀土之漿料。用濾 紙（No · 5 C、東洋濾紙（股））過濾氫氧化稀土之漿料， 回收固體成分約120g。 於回收之固體成分加水1升後，邊攪拌邊以95 °C之 液溫加熱。於此液加入濃度35質量％之鹽酸182g，再添 (20) 1231805 加濃度30質量％之過氧化氫水21g以溶解固體成分，得 到黃色透明或綠色透明之氯化稀土水溶液。 用濾紙（N 〇. 5 C、東洋濾紙（股））過濾此液，將濾 液回收於燒杯。邊攪拌回收之濾液，邊滴液濃度5質量％ 之氨水，將pH値調整爲1〜2。於此液添加攪拌濃度20 質量％之碳酸氫銨水溶液8 3 3 g，成碳酸稀土漿料。 用濾紙（No.5C、東洋濾紙（股））過濾此碳酸稀土 漿料回收固體成分約1 97g。於回收之固體成分加入純水 1.5升攪拌後，用濾紙（No· 5C、東洋濾紙（股））過濾 回收固體成分。此作業反覆至pH値爲6〜8之中性漿料 止。 將回收之固體成分以1 000°C燒焙1小時得到氧化稀 土類約9 5 g。 爲氧化稀土類所得之回收物之組成示於表1。 實施例3 (稀土類氧化物之回收） 自硬碟用玻璃基板之硏磨步驟經排出具有表1所示之 固體成分組成之硏磨廢液依下述順序回收稀土類氧化物。 將含有相當於100g固體成分之硏磨廢液0.5升，與 濃度35質量％之鹽酸25 0g收容於附冷水管之燒瓶，之後 加熱，將此燒瓶內溶液之溫度保持於103 °C。此時，經 由加熱產生之蒸氣於冷水管液化返回燒瓶內，防止液面降 低。加熱4 8小時後，硏磨廢液成綠色含有稀土類氯化物 酸性水溶液，與白色矽膠，與硏磨墊屑等未溶解物之混合 -24- (21) 1231805 液。 再自燒瓶取下冷水管，之後加熱濃縮該混合液使容量 成一半。經由加熱濃縮，矽膠及未溶解物浮起於含有稀土 類氯化物酸性水溶液。 之後，自燒瓶取樣此濃縮液’用濾紙（No.5C、 Adbanteck東洋濾紙（股））過濾，自含有稀土類氯化物 酸性水溶液分離·去除未溶解物。 經由加熱濃縮操作，自含有稀土類氯化物酸性水溶液 爲去除大部份之矽膠，利用濾紙過濾分離時間自約1小時 大幅被縮短至約1 〇分鐘。又經由加熱濃縮操作，幾乎無 被包入於矽膠之含有稀土類氯化物酸性水溶液，較之無加 熱濃縮操作，含有稀土類氯化物酸性水溶液之收率最後以 稀土類氧化物換算自82%提高爲98%。 又將加熱濃縮時產生之蒸氣引進附冷水管之燒瓶使其 液化，以鹽酸回收。此鹽酸得再利用爲原料。 再將經由過濾回收之含有稀土類氯化物酸性水溶液用 水稀釋成總量1升，於此液添加濃度質量1 0%之碳酸氫銨 水溶液1 65 3 g，之後攪拌得到稀土類碳酸鹽之白色沉澱 物。 用濾紙（No.5C、Adbanteck東洋濾紙（股））過濾 含此沉澱物之水溶液之後洗淨。 將所得之固體物收容於磁製容器，於大氣中以1〇〇〇 °C燒焙1小時得到稀土類氧化物9 8 g。 所得稀土類氧化物之組成示於表1。 -25- (22) 1231805 實施例4 (稀土類氧化物之回收） 自液晶顯示器（LCD )用玻璃基板之硏磨步驟經排出 具有表1所示之固體成分組成之硏磨廢液依下述順序回收 稀土類氧化物。 將含有相當於l〇〇g固體成分之硏磨廢液〇.5升，與 濃度35質量％之鹽酸25 0g收容於附冷水管之燒瓶後，加 熱並保持於10 3 °C。加熱4 8小時後，此硏磨廢液成綠色 之含有稀土類氯化物酸性水溶液，與白色矽膠，與硏磨墊 屑等未溶解物之混合液。 再自燒瓶取下冷水管，之後於該混合液浸沉沸石後加 熱濃縮使容量成一半。經由加熱此混合液中以沸石爲起點 產生細微氣泡，隨之矽膠、硏磨屑等未溶解物同時浮起溶 液之液面上。再此已浮起之矽膠及未溶解，經由氣泡移動 燒杯之內壁側，或經由蒸發使液面降低黏著於燒杯內壁。 黏著於燒杯內壁之矽膠因經由燒杯內壁再使其發熱引起體 積收縮，釋放包入之含有稀土類氯化物酸性水溶液。無此 加熱濃縮操作時之含有稀土類氯化物酸性水溶液之收率最 後以稀土類氧化物換算爲73 %。經由此加熱濃縮操作，含 有稀土類氯化物酸性水溶液之收率提高爲95%。 之後用濾紙（No.5C、Adbanteck東洋濾紙（股） 製）過濾此濃縮液，將殘留之未溶解物自含有稀土類氯化 物酸性水溶液分離去除。利用該加熱濃縮操作，爲自含有 稀土類氯化物酸性水溶液去大部份之矽膠，利用濾紙過濾 -26- (23) 1231805 分離時間自約3小時大幅被縮短至約1 0分鐘。 再將此含有稀土類氯化物酸性水溶液用水稀釋成2升 之水溶液。之後於此液添加濃度1 0質量％之草酸水溶液 4 5 0g，攪拌得到稀土類草酸鹽之白色沉澱物。 用濾紙（No.5C、Adbanteck東洋濾紙（股））過濾 含此沉澱物之水溶液，之後洗淨得到沉澱物。 將所得之沉澱物收容於磁製容器，於大氣中以1 〇〇〇 °C燒焙1小時得到稀土類氧化物9 5 g。 所得稀土類氧化物之組成示於表1。 實施例5 (稀土類氧化物之回收） 將同於實施例3所得之含有稀土類氯化物酸性水溶液 用水稀釋成總量1升之水溶液，於此液添加濃度1 0質量 %之碳酸氫化鈉水溶液l〇98g，之後攪拌得到稀土類碳酸 鹽之白色沉澱物。 用濾紙（No.5C、Adbanteck東洋濾紙（股））過濾 含此沉澱物之水溶液，之後洗淨將所得之固體物收容於磁 製容器，於大氣中以1 000 °C燒焙1小時得到稀土類氧化 物 92g。 所得稀土類氧化物之組成示於表1。 實施例6 (經回收之稀土類氧化物硏磨材之再利用） 反覆實施例5所載之方法，使用經回收之稀土類氧化 物，經由下述之操作成硏磨材再利用，評估該硏磨性能。 -27- (24) 1231805 (i )於反覆實施例5所得之稀土類氧化物5 kg加水 成濃度50質量％之漿料後，再加入150g之分散劑（聚丙 烯酸鈉），經高分散處理機（ULTRA-TURRAXtm、 T50basic、IKA-WERKE 公司）成漿料。 (ii )再經介質型破碎機（球磨機）濕式破碎，再濕 式淘汰管分級得到硏磨用之漿料。分級之結果，分別得到 少量之含不作硏磨用漿料之粗粒之漿料及含微粒之漿料。 下次處理時對於含粗粒之漿料返回破碎步驟，於硏磨材混 合含微粒之漿料，再利用。 (iii )使用此硏磨用漿料實施玻璃碟之硏磨加工，提 取當時之硏磨材。用於硏磨加工時用洗淨水，硏磨材之固 體成分濃度爲1 〇質量％。 (i v )將此硏磨材用裝入聚乙烯槽之攪拌機攪拌，同 時加入濃度3 5質量％之鹽酸pH値爲5後停止攬拌機，靜 置懸濁漿料使其沉澱後去除澄淸液體得到濃度2 8質量°/〇 之漿料。 (v)將此漿料3.5kg放入10升之玻璃製可拆式燒 瓶。再加入8.4kg之濃度20質量％之鹽酸。 (vi )於可拆式燒瓶附冷水管及棒溫度計、二方型栓 成三口可拆式燒瓶蓋後，放入覆套式電阻加熱器加熱。此 時產生之蒸氣於冷水管冷卻後返回可拆式燒瓶內。 (vii )於液溫120 °C加熱3小時後，將附二方型栓與 冷水管之6升燒瓶用管連接，關閉1 0升可拆式燒瓶之冷 水管後，打開二方型栓，將蒸氣引入附冷水管之6升燒瓶 -28- (25) 1231805 冷卻回收殘留之鹽酸。此鹽酸於下次溶解時再使用。 (viii )經由此操作濃縮10升可拆式燒瓶內之氯化稀 土水溶液，浮起未溶解物及矽膠黏著於容器內壁。 (i X )停止覆套式電阻加熱器之加熱後，取下棒溫度 計將玻璃管插入可拆式燒瓶底部，吸入回收氯化稀土水溶 液。 (X )將反覆上述（v )至（ix )操作所得之氯化稀土 水溶液用過濾器過濾後，加入碳酸氫銨得到碳酸稀土漿 料。再用離心脫水機分離固體液，得到碳酸稀土之固體 物。接著燒焙得到稀土類氧化物。所得稀土類氧化物之組 成示於表1。 (26)12318051231805 (1) 发明. Description of the invention [Technical field to which the invention belongs] The present invention relates to a method for recovering rare earth oxides from a waste liquid containing rare earth elements, and particularly relates to a method for recovering rare earth oxides from a honing waste liquid containing rare earth elements. A method for recovering high-quality rare earth oxides by using honing materials for high-precision honing processing. [Previous Technology] In recent years, honing materials containing rare earth elements have been used in various fields. In particular, honing materials are mostly used for honing glass materials or crystals. For example, glass substrates for optical discs or magnetic disks, thin-film transistor (TFT) type liquid crystal displays (LCDs) or twisted nematic (TN) liquid crystal displays (LCDs), glass substrates for liquid crystal displays, and color for liquid crystal televisions (TVs) Hoses for cathode ray tubes (CRT) for filters, televisions, spectacle lenses, optical lenses, glass substrates for large-scale integration (LSI) photomasks, inlaid flat glass, and substrates for crystal vibrators. The honing material containing rare-earth elements referred to herein refers to a fine-grained honing material containing rare-earth element oxides such as cerium (Ce), lanthanum (La), praseodymium (Pr), and praseodymium (Nd). Ores containing rare earth element honing materials, such as fluorite cerium or phosprosite lanthanum are produced in China and the United States. The rare earth oxides produced from ores such as fluorocarbon osmium ore or phosphatite lanthanum ore are usually subjected to the following treatments 1) to 9) in order. 1) In a rotary kiln, slowly add sulfuric acid to the ore to mix and dry. -5- (2) 1231805 2) Baking by heating to 5 0 ° C ~ 6 0 t. 3) The roasted ore is leached with water, so that the rare earth-containing substances are dissolved and dissolved out of water. 4) Concentrate with thickener, filter out impurities such as BaS04, CaS04, S102, and get R 2 (S Ο 4) 3. R is a rare earth element in the formula. 5) Add sodium sulfate to R2 (S04) 3 to separate iron, calcium, phosphoric acid, etc., to obtain the double salt of sulfuric acid of rare earth elements. 6) Add sodium hydride to the double salt of sulfuric acid of rare earth element to precipitate the hydroxide of rare earth element. 7) Add hydrochloric acid to the hydroxide of rare earth element as the chloride of rare earth element. 8) Add ammonium bicarbonate to the rare earth element chloride to form a rare earth carbonate. 9) Roasting rare earth carbonates into rare earth oxides. However, the ore reserves of honing materials containing rare earth elements are limited. Recently, as the demand for honing materials containing rare earth elements has increased, the problem is that the raw materials have insufficient ore. Therefore, it is desirable to recover the rare earth oxides from the honing waste liquid containing rare earth elements for reuse as a honing material. In addition, the field of use of honing materials that are not mainly composed of rare earth oxide powders has increased requirements for high-precision processed materials. The quality of the honing materials is required to reduce coarse particles and foreign materials. However, it is difficult to recover high rare earth oxides from the honing waste liquid containing rare earth elements, which can be reused as a honing material for high precision honing processing. In particular, rhenium-containing rare earth oxides containing rhenium are used to grind glass or crystal -6- (3) 1231805, etc., by mixing them with water, dispersant, and surfactant to form a slurry. This is because the honing waste liquid containing rare earth elements contains at least honing materials, honing pads, etc. of honing materials, water, dispersant, surfactant, glass and the like. And honing waste liquid containing rare earth elements, compared with ore containing rare earth elements, the content of rare earth elements, the respective ratio of rare earth elements, the content of other than rare earth elements, the content ratio of such contents There are many differences. For this reason, the high-quality high rare-earth oxides that are used as honing materials are recovered and reused from honing waste liquids containing rare earth elements other than sisters, which is extremely costly and impractical. Many methods have been proposed for recovering honing materials containing rare earth oxide fine powders by using honing wastes produced by honing when honing materials containing rare earth elements are used. For example, after washing the honing waste liquid with alkali, screening the impurities such as dust and honing materials (such as refer to Patent Document 1), the honing waste liquid is dissolved with sulfuric acid to form oxalate, and then neutralized with alkali to form rare earths. A method for recovering oxides (see, for example, Patent Document 2), a method for recovering rare earth elements by dissolving glass shavings in a honing waste solution with hydrofluoric acid (for example, see Patent Document 3), and condensing the honing waste solution, The method of liquid separation to recover rare earth elements (for example, refer to Patent Document 4) is suggested. [Patent Document 1] Japanese Patent Application Laid-Open No. 1 1-9082 5 (Page 2-5) [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-87 1 54 (Page 3-5) [Japanese Patent Application Laid-Open No. 3] 1 1 -3 1 97 5 Publication No. 5 (page 2-3, Fig. 1) (4) 1231805 JP-A 1 0-2 8 0 06 0 Publication (page 3-5) The method of recovering rare earth oxides is insufficient to remove foreign substances, and it is impossible to obtain high quality rare earth oxides which are industrially useful as a honing material for high precision honing processing. [Summary of the Invention] [Problems to be Solved by the Present Invention] In view of the above circumstances, the object of the present invention is to provide a liquid containing rare earth elements, which can recover high-quality rare earth oxides with high efficiency and complete high purity. The method, especially the recovery of waste liquid containing rare earth elements, is helpful for industrial reuse of high quality rare earth oxides as a honing material for high precision honing processing. [Means to Solve the Problem] The inventors discovered that by combining a specific purification method (such as (1) mixing and heating a liquid containing a rare earth element with an acid to dissolve the rare earth element in the liquid, (2) from (1) Remove the undissolved matter from the obtained rare earth element solution, (3) Add the soluble rare earth element or bicarbonate or oxalic acid to the solution of rare earth element obtained in (2) to form carbonic acid Rare earth or rare earth oxalate, (4) separating rare earth carbonate or rare earth oxalate from the slurry containing rare earth carbonate or rare earth oxalate obtained in (3), (5) roasting the separated rare earth carbonate or rare earth oxalate into rare earth oxides, and then ( 6) Recover the rare earth oxide produced.) From the honing waste liquid containing rare earth elements, it can be reused as the high quality honing rare earth oxide-8- (5) 1231805 The recovery of rare earth oxides is advantageous for industrial purposes, and based on this knowledge, the present invention has been completed. According to the present invention, the invention provides the following recovery method of rare earth oxides, a manufacturing method of honing materials, a recycling method, and a honing method. 1. A method for recovering rare earth oxides from a liquid containing rare earth elements, which is characterized by including the following steps (1) to (6); (1) mixing and heating a liquid containing rare earth elements with an acid to dissolve the solution (2) removing undissolved matter from the solution of the rare earth element obtained in step (1), (3) adding a soluble carbonate or bicarbonate or a solution of the rare earth element obtained in step (2) The rare earth elements in the solution of oxalic acid become rare earth carbonate or rare earth oxalate, (4) separating the rare earth carbonate or rare earth oxalate from the slurry containing rare earth carbonate or rare earth oxalate obtained in step (3), (5) roasting the separated carbonate Rare earth or rare earth oxalate becomes rare earth oxide, and (6) the produced rare earth oxide is recovered. 2. The method according to item 1, wherein step (1) is a step of mixing and heating a liquid containing a rare earth element with an acid and hydrogen peroxide to dissolve the rare earth element in the waste liquid. 3. The method according to item 1 or 2, wherein the acid in step (1) is hydrochloric acid. 4. The method according to item 1 or 2, wherein the acid in step (1) is -9-(6) 1231805 nitric acid. 5. The method according to any one of items 1 to 4, wherein step (1) is heating and concentrating the mixed liquid obtained by mixing the acid under reflux, so that the undissolved solid contained in the mixed liquid floats on the liquid surface. 6. The method of item 5 is to generate bubbles while condensing. 7. The method of item 6 is to heat the mixed solution in the presence of anti-zeolite to cause bubbles. 8. The method according to item 1, wherein in step (2), undissolved matter is removed by filtration. 9. The method according to item 1, wherein in step (3), the pH of the rare earth element solution is adjusted to 1 to 7, and then the solution is added with a soluble carbonate or bicarbonate or oxalic acid to the solution. Rare earth carbonate or rare earth oxalate. 1 0. The method according to item 9, wherein in step (3), the pH is adjusted to 1 to 7 with ammonia. 1 1. The method according to item 1 or 9, wherein the soluble carbonate or bicarbonate in step (3) is an alkali metal salt, alkaline earth metal salt or ammonium salt. 12. The method according to item 1, wherein the rare earth carbonate or rare earth oxalate is separated by filtration in step (4). 1 3 · —A method for recovering rare earth oxides from a liquid containing rare earth elements', which is characterized by including the following steps (i) to (vi); (i) mixing and heating a liquid containing rare earth elements with sulfuric acid Taking the rare earth element in the dissolving solution as rare earth sulfate, -10- (7) 1231805 (ii) mixing the rare earth sulfate with water to dissolve the rare earth sulfate '(Hi) removing undissolved matter from the obtained rare earth sulfate solution' (iv) Sodium sulfate is added to the obtained solution to form a double salt of a rare earth element, and the double salt is separated from the solution. (V) The double salt is suspended in water, and the double salt of a rare earth element having a pH of 8 to 13 is hydrogen. The rare earth is oxidized, and (vi) the rare earth hydroxide is separated and recovered. 14. The method according to item 13, wherein in step (iii), undissolved matter is removed by filtration. 15. The method according to item 13, wherein in step (v), the pH of the suspension is adjusted to 8 to 13 by adding alkali, ammonia water or ammonia gas. 16 · The method according to item 13 of the scope of patent application, wherein in step (i) is a solution containing rare earth elements, adding aluminum sulfate, polyaluminum chloride or a polymer coagulant to precipitate a solid containing rare earth elements Components, the precipitate was separated and recovered, and sulfuric acid was added to the recovered material. 1 7 _ The method according to item 13 or 16, wherein step (i) comprises mixing sulfuric acid in a liquid containing a rare earth element, and then adding hydrogen peroxide water. 18. A method for recovering rare earth oxides, which is characterized by recovering rare earth hydroxide from a liquid containing rare earth elements using the method of any one of items 13 to 17 and baking the same. 19. A method for recovering rare-earth oxides, which is characterized by recovering rare-earth hydroxide from a solution containing rare-earth elements using the method of any one of items 13 to 17, and suspending this in water. The method according to any one of 1 to 12. -11-(8) 1231805 20. The method according to any one of items 1 to 19, wherein the liquid containing rare-earth elements is a waste liquid generated by honing and honing materials. 2 1 · A manufacturing method of a honing material using a rare earth oxide, characterized in that it includes a recycler using any one of the methods 1 to 20. 22 · —Recycling method of honing materials, characterized in that the waste liquid generated from the honing materials is used to recover rare earth oxides by using the method of any one of items 1 to 20, including those who obtain honing materials . 23 · A honing method, characterized in that the waste liquid generated from the honing honing material is recovered by the method of any one of items 1 to 20, and the honing material obtained is used for honing . [Mode for Carrying Out the Invention] A method for recovering a high-quality rare earth oxide from a honing waste liquid containing a rare earth element will be described below with examples and steps according to the present invention. In addition, the recovery method of the present invention generally recovers a plurality of rare earth oxides from a honing waste liquid containing a plurality of rare earth elements. However, it can also be obtained from the honing waste liquid containing a specific rare earth element (such as thorium) with an extremely high relative ratio, and the rare earth oxide containing the rare earth element with an extremely high relative ratio is recovered. The composition of the rare earth element contained is not particularly limited. Step (1) (dissolving the rare earth elements in the waste liquid to obtain a rare earth solution step) First, the honing waste liquid containing the rare earth elements is stored in the reaction capacity -12- (9) 1231805 Add acid or add acid and hydrogen peroxide and heat. The acid used herein may be an acid which can dissolve the rare earth elements contained therein, and is preferably selected from hydrochloric acid, nitric acid and sulfuric acid. Preferred are hydrochloric acid and nitric acid, and most preferred is hydrochloric acid. The heating system can at least completely dissolve the rare earth elements (usually in the form of rare earth oxide) in the waste liquid for heating. If the acid used is hydrochloric acid, the heating temperature is preferably 90 ° C ~ 120 ° C. Preferably, it is stirred in the range of 90 ° C to 120 ° C for 5 hours to 72 hours, heated under reflux and concentrated. The concentration of hydrochloric acid added to the honing waste liquid is not limited, but is generally 15 to 45 mass%, preferably 20 to 35 mass%, and concentrated hydrochloric acid having a concentration of 35 mass% may be used. The amount of hydrochloric acid to be added is preferably in the range of 200 to 5000 parts by mass, which is 35% by mass based on 100 parts by mass of the solid content in the honing waste liquid. The concentration of nitric acid added to the honing waste liquid is not limited, and generally it is suitable to use 62 to 98% by mass. The amount of nitric acid added is preferably in the range of 112 to 177 parts by mass of 100 parts by mass of the solid component in the honing waste liquid. If non-reducing acids such as nitric acid or sulfuric acid are added, the oxidation of rare earths is suppressed, and the acid and rare earths of rare earth nitrate or sulfuric acid are reduced as much as possible. To improve the solubility, it is advisable to use reducing substances such as hydrogen peroxide . Through the use of hydrogen peroxide, etc., the effect of decomposing and removing organic substances present in the honing waste liquid can also be obtained. The amount of hydrogen peroxide used is preferably in the range of 9 to 27 parts by mass of 100 parts by mass of nitric acid. If hydrochloric acid is added, it can be used as desired when decomposing organic matter. Heat the acid or add acid and hydrogen peroxide to dissolve the rare earth oxides. For example, an acidic -13- (10) 1231805 aqueous solution containing rare earth elements such as rare earth chloride or rare earth nitrate can be obtained. At this time, the glass abrasion powder contained in the honing waste liquid becomes a silica sol, then progresses to gelation, and finally becomes a silica gel. Here, the undissolved materials such as silicone rubber and honing pads can be separated by filtration as it is, but it is an acidic water-soluble solution that contains rare earth elements. It is used to recover the acidic aqueous solution of rare earth elements with high efficiency. should. If the acidic aqueous solution of rare earth elements is heated and concentrated again, the specific gravity (concentration) of the acidic aqueous solution is increased, so the silicone contained in the aqueous solution becomes relatively light, and the undissolved matter floats on the liquid surface at the same time, which is easy. Isolation of the acidic aqueous solution in the following step (2). If the acidic aqueous solution of rare earth elements is heated and concentrated again, the silicon surface and undissolved substances floating on the liquid surface will stick to the inner wall of the reaction vessel because the liquid surface is lowered. When there is more silicone and undissolved matter than the area of the inner wall of the reaction container, a partition plate or the like can be provided inside the reaction container to increase the area of the inner wall. If the adhered and fixed silica gel and undissolved matter are heated again, the volume shrinks, and an acidic aqueous solution of rare earth elements containing silica gel and undissolved matter is discharged. For this reason, it is preferable that the temperature of the inner wall, the partition plate, and the like is likely to cause volume shrinkage to maintain the liquid temperature above, and is preferably about 40 to 60%. After heating and concentrating, the silica gel and the undissolved matter are separated from the acidic aqueous solution of the rare earth element to improve the recovery rate of the acidic aqueous solution of the rare earth element in the next step (2). When concentrating an acidic aqueous solution of rare earth elements, it is preferable to generate bubbles while concentrating. It is preferable to generate fine and uniform bubbles. If the zeolite is immersed in this aqueous solution, a lot of air bubbles are generated from the zeolite as a starting point through heating, and the generated air bubbles are fine and uniform. Silicone and undissolved matter float with the bubbles at the same time. For this reason, the separation of the silicon gel and the insoluble -14- (11) 1231805 in step (2) and the acidic aqueous solution of rare earth elements can be promoted. In addition, it is preferable to use ceramics, plastics, or the like which are insoluble in the heat-dissolved glass or the like using the antizeolite, and it is preferable to have a shape having a plurality of protruding portions which are the starting points of bubbles. Step (2) (Separation step of an acidic aqueous solution of rare earth elements) Then, an acidic aqueous solution of rare earth elements is selected from the reaction container to separate and remove undissolved matters such as silicon gel and honing pads remaining in the liquid. The method of separation and removal is not particularly limited, and filtration or centrifugation may be applied. It is better to filter easily. And remove the undissolved matter and take out the acidic aqueous solution of rare earth elements. Step (3) (Step of generating rare earth carbonate or rare earth oxalate from solution of rare earth element) Next, add soluble carbonate or bicarbonate or oxalic acid to the acidic aqueous solution of the rare earth element to form the rare earth element in the solution into Rare earth carbonate or rare earth oxalate. Soluble carbonate or bicarbonate can be the soluble salt of the solution (acidic solution) in step (3). The alkali metal salt, alkaline earth metal salt or ammonium salt is suitable. The alkali metal salt is sodium, potassium, lithium, etc., and sodium and potassium are suitable. Alkaline earth metal salts are used for calcium, rubidium, barium, etc. Among alkali metal salts, alkaline earth metal salts and ammonium carbonates and bicarbonates, sodium bicarbonate and potassium bicarbonate are preferred. Most preferred is ammonium bicarbonate. Add such carbonate, bicarbonate or oxalic acid in advance according to the schedule, in order to suppress the particle size of -15- (12) 1231805, the acidic aqueous solution of rare earth elements can be diluted with water. The particles that are usually diluted become larger. In addition, after adjusting the pH of the acidic aqueous solution of the rare earth elements to 1 to 7, preferably 1 to 3, it is preferable to add ammonium bicarbonate or oxalic acid. PΗ 値 is adjusted by adding alkaline components such as ammonia water, sodium hydroxide, potassium hydroxide, and calcium hydroxide, and it is preferable to use ammonia water which is easy to remove the alkaline components. If ammonia water is used, the concentration is not particularly limited and is usually selected in the range of 5 to 28% by mass. The carbonates and bicarbonates of alkali metals, alkaline earth metals, and ammonium can be added in the form of a solid or an aqueous solution, but an aqueous solution is preferred. The concentration of such an aqueous solution of carbonates and bicarbonates and the concentration of oxalic acid are not particularly limited, and they may be appropriately selected in the range of 5 to 97% by mass. The alkali metal, alkaline earth metal, ammonium carbonate, bicarbonate, and oxalic acid are preferably added in a range of 193 to 540 mass parts for 100 parts by mass of rare earth elements. The carbonate or bicarbonate, oxalic acid, and an acidic aqueous solution containing a rare earth element are added to form a slurry containing a rare earth carbonate or a rare earth oxalate. Step (4) (a step of separating rare earth carbonate or rare earth oxalate) The slurry containing rare earth carbonate or rare earth oxalate is further separated by, for example, filtration to separate rare earth carbonate or rare earth oxalate. The separated rare earth carbonate or rare earth oxalate was washed with water and filtered again as expected. Step (5) (Roasting step of rare earth carbonate or rare earth oxalate) Then roast the separated rare earth carbonate or rare earth oxalate to form rare earth oxide -16- (13) 1231805. The baking system uses rare earth carbonate or rare earth oxalate in the atmosphere from 600 to 12 00. (: It is suitable to carry out at about 800 to 1 1 0 ° C for about 0.5 to 3 hours, and preferably about 0.5 to 2 hours. A baking furnace may use a box furnace, a rotary furnace, and an air duct. Furnace, etc., usually use a roaster. Step (6) (recycling step of rare earth oxides) Recovery of rare earth oxides obtained by roasting, adjusting the size (granularity and distribution) of pulverization, and then using them for precision honing The honing material used. Generally the particle size of the original honing material particles can also be changed. For example, the average particle size can be obtained from 0. The range is 1 ~ 2 μm. According to the method for recovering rare earth oxides, high-quality rare earth oxides that can be reused as honing materials for precision honing can be obtained. Before step (1), the following steps (i) to (iv) are performed. After processing, the obtained rare-earth hydroxide-containing slurry is used as the rare-earth element containing step (1). By performing steps (1) to (6), a high-quality rare-earth oxide with higher purity can be obtained. (i) mixing the liquid containing rare earth elements with sulfuric acid and heating to convert the rare earth elements in the liquid into rare earth sulfate, (Π) mixing the liquid containing the rare earth sulfate with water to dissolve the rare earth sulfate, () from the obtained sulfuric acid Rare earth solution to remove undissolved matter, (iv) adding sodium sulfate to the resulting solution to form a double salt of rare earth elements, and then separating the double salt, -17- (14) 1231805 (v) suspending the double salt in water, and pH 値It is a double salt of a rare earth element of 8 to 13 to a rare earth hydroxide, and (vi) the rare earth hydroxide is separated and recovered. The following description includes processing before the steps (i) to (vi). Step (i) (the step of turning the rare earths in the waste liquid into rare-earth sulfate) Add sulfuric acid to the honing waste liquid containing rare-earth elements and heat. The concentration of sulfuric acid is not particularly limited. For example, concentrated sulfuric acid having a concentration of 95% to 99% by mass is used. The amount of sulfuric acid is preferably 80 to 450 parts by mass of 100 parts by mass of solid components in the honing waste liquid. The heating system is heated at 90 ° C to 120 ° C for 10 minutes to 1 hour. Hydrogen peroxide is added to the sulfuric acid-added solution to remove organic components such as the monomer carbon that decomposes the honing pad into carbon gas. After adding hydrogen peroxide, the solution was heated at 200 ° C to 600 ° C for another 1 minute to 1 hour, and the rare earth elements in the solution were turned into rare earth sulfate. It is appropriate to separate the rare earth sulfate by decantation or filtration. Step (i i) (the step of adding water to the rare earth sulfate to dissolve the rare earth sulfate) and then adding water to the separated rare earth sulfate or rare earth sulfate containing liquid to dissolve or dilute the rare earth sulfate. Thereby, in the next filtering step (i i i), glass dust or honing pads can be efficiently removed. The amount of water used for dissolving or diluting is selected from the range of 5-25 mass parts to 1 900 mass parts for the 100 mass parts of rare earth sulfate solid content. (15) 1231805 Step (iii) (the step of removing undissolved matter from the diluted rare earth sulfate solution) The diluted rare earth sulfate solution is used to remove glass shavings or honing pads by filtering and other methods. Step (iv) (the step of adding a sodium sulfate to the furnace liquid to form a double salt of a rare earth element) After filtering the diluted rare earth sulfate solution ', adding sodium sulfate to the filtrate to form a double salt of a rare earth element. Sodium sulfate is added as a solid or as an aqueous solution. That is, sodium sulfate or an aqueous solution thereof having a concentration of 5 mass% to 100 mass% is added to 1. 25 ~ 95 quality parts to add 12. 5 ~ 80 mass part is suitable. 'Rare earth elements such as R2 (S04) 3. Na2S04. 2H20 (R series rare earth element) slurry. An additional separation operation, such as filtering the slurry, is used to separate and remove the solution to obtain a double salt. Step (v) (the step of adding a double salt of a rare earth element containing alkali to a double salt to form a rare earth hydroxide) The double salt obtained in the previous step (iv) is added with water, and the double salt of a rare earth element having a pH of 8 to 13 is added. Into rare earth hydroxide. It is advisable to adjust the pH to pH 8 to 13 by adding alkali, ammonia or ammonia gas. It is preferably 1 2 to 1 3 °. Adjusting pH 値 to this range can improve the solubility of the following steps' and improve the recovery of rare earth elements. As a base, sodium hydroxide, potassium hydroxide, etc. are used. The base is added as a solid form -19- (16) 1231805 or an aqueous solution. Usually, an alkali aqueous solution having a concentration of 10 to 95% by mass is added to a solution of 100 parts by mass of the double salt to 33 to 32 parts by mass. The amount of ammonia water or ammonia gas is converted into ammonia (NH3), and it is usually in the range of 3 to 30 parts by mass. Step (vi) (the step of recovering the rare earth hydroxide) The solution containing the rare earth elements, such as filtration, is used to recover the source of the rare earth hydroxide. This recovered rare earth hydroxide is suspended in water for the processing steps following step (1). In another aspect, the rare earth hydroxide recovered in step (W) will not be used for the processing steps below step (1), and the rare earth hydroxide will be roasted in the atmosphere at 600 ° C ~ 14 0 ° C. Into rare earth oxides. The rare earth element obtained by changing the state can be reused as a honing material, but its quality is slightly inferior to that of the rare earth oxide obtained through steps (1) to (6). In addition, before step (i) of the present invention, before adding sulfuric acid, add aluminum sulfate, polychlorinated aluminum or polymer coagulant to the waste liquid containing rare earth elements to precipitate solid components containing rare earth elements to separate them. Pre-treatment to recover the precipitate. After the pretreatment, sulfuric acid was added to the recovered product. Aluminum sulfate and polyaluminum chloride can be solid or aqueous solutions (usually at a concentration of 10% by mass or more). Examples of the polymer coagulant that can be used in the present invention include commercially available products such as Kuflock (made by Kurita Industry Co., Ltd.) and Orflock (made by Organo Company). After the rare earth oxides recovered in the above steps (1) to (6), the pulverized particle size (particle size and distribution) is sorted, and then it can be reused as refined -20- (17) 1231805 Honing material for dense concrete . The use of this honing material is the same as that of the original ore. It is made of fine powder of rare earth oxides such as cerium (Ce), lanthanum (La), praseodymium (Pr), and neodymium (Nd). Fields of use of honing materials, such as glass substrates for optical discs or magnetic disks, thin-film transistor (TFT) type liquid crystal displays (LCD) or twisted nematic (TN) type liquid crystal displays (LCD), and other glass substrates for liquid crystal displays, liquid crystal Honing of color filters for televisions, cathode ray tubes (CRTs) for televisions, spectacle lenses, optical lenses, glass substrates for LSI masks, inlay flat glass, substrates for crystal vibrators, etc. [Embodiments] [Examples] The present invention will be specifically described below based on examples, but the present invention is not limited thereto. Example 1 (recycling of rare earth oxides from honing waste liquid) The honing waste liquid produced by the honing of a glass dish was to recover rare earths from a honing waste liquid having a solid composition shown in Table 1. To 1 liter of honing waste liquid, 38 g of aluminum sulfate with a concentration of 20% by mass and a polymer coagulant (Kuflock; manufactured by Kurita Industry Co., Ltd.) were added. 2g, the mixed solids were allowed to coagulate and precipitate for separation and recovery. 100 g of the recovered solid content was placed in a beaker to which 95% by mass of concentrated sulfuric acid was added, and stirred for 5 minutes. The beaker was heated at 1000 ° C, and the organic matter was decomposed into a black liquid by the dehydration effect of hot sulfuric acid. Then, -21-(18) 1231805 20 g of the hydrogen peroxide water droplets as a carbon dioxide gas are removed. After this treatment, organic matter contained in honing waste liquid containing rare earth elements can be removed. The beaker was heated at 300 ° C to a rare earth sulfate in the form of a yellow solid. This rare earth sulfate was dissolved in 5 ° C cold water to form a brown transparent sulfuric acid aqueous solution. This acidic aqueous solution of sulfuric acid containing rare earth sulfate was filtered to remove undissolved matters such as glass dust. After this treatment, in addition to glass, carbides and the like are also removed. The filtrate was added with 413 g of a Na2S04 aqueous solution having a concentration of 10% by mass and stirred to give a double salt. After recovering this double salt by filtration, 1,500 g of pure water was added to form a slurry, and 85.1 g of a sodium hydroxide aqueous solution having a concentration of 20% by mass was added, followed by stirring to form an alkaline rare earth hydroxide slurry. This rare earth hydroxide slurry was filtered, and about 110 g of a rare earth hydroxide solid was recovered. The pH during this treatment is 1 1. 7. The recovered solid was mixed with 1,500 g of pure water to form a slurry, and then heated at 95 t to dissolve and add 182 g of a 35 mass% hydrochloric acid solid to a rare earth chloride aqueous solution. The rare earth chloride aqueous solution at this time is a yellow transparent liquid or a green transparent liquid. This rare earth chloride aqueous solution was filtered to remove undissolved matter. • Add 163 g of a 10% by mass ammonium bicarbonate aqueous solution to the filtrate to a rare earth chloride aqueous solution and stir to obtain a white precipitate of rare earth carbonate. This precipitate was filtered, and the solid matter obtained after washing was put into a magnetic container, and baked at 1 000 ° C for 1 hour to obtain 93 g of rare earth oxides. Table 1 shows the composition of the recovered materials obtained by oxidizing rare earths. -22- (19) 1231805 Example 2 (recovering rare earth oxides from the honing waste liquid) The honing waste liquid produced by the honing of the glass filter is a honing waste liquid composed of the solid components shown in Table 1. Recycling rare earths. In a stainless steel (SUS) beaker containing 245 g of sulfuric acid having a concentration of 98% by mass, 100 g of recovered powder was added and stirred with a stainless steel spatula and covered with a surface glass. This beaker was placed on a heater, heated at 600 W for 30 minutes, and left to cool. The resulting yellow solid was transferred to a mortar and crushed with a pestle. Add 1 liter of cold water to a beaker surrounded by ice water and stir. This cold water is slowly added to the crushed matter and mixed to form a sulfuric acid aqueous solution (brown transparent liquid) of rare earth sulfate. Use filter paper (No. 5 C. Toyo filter paper (strand)) The acidic aqueous solution of sulfuric acid containing rare earth sulfate was filtered, and the filtrate was recovered. To the filtrate, 276 g of a 15% by mass sodium sulfate aqueous solution was added and stirred. Then, about 76.9 g of a 20% by mass sodium hydroxide aqueous solution was added and stirred at a pH of 6 to generate a double salt. Use filter paper (NO. 5C, Toyo filter paper (strand)) filtered the double salt, and recovered about 2 17 g of solid content in a beaker. Add water to the recovered solid content and stir to about 1. 5 liters of slurry. Then, a 20% by mass sodium hydroxide aqueous solution was added to the slurry, and the slurry was stirred at a pH of 12 to a rare earth hydroxide. The rare earth hydroxide slurry was filtered with a filter paper (No. 5 C, Toyo filter paper (strand)), and about 120 g of a solid content was recovered. After adding 1 liter of water to the recovered solid content, heat at 95 ° C while stirring. To this solution was added 182 g of 35% by mass hydrochloric acid, and (20) 1231805 was added 21g of 30% by mass hydrogen peroxide water to dissolve the solid content to obtain a yellow transparent or green transparent rare earth chloride aqueous solution. Use filter paper (NO. 5 C, Toyo filter paper (strand)) This solution is filtered, and the filtered solution is recovered in a beaker. While stirring the recovered filtrate, an aqueous ammonia solution having a concentration of 5% by mass was dropped, and the pH was adjusted to 1 to 2. To this solution, 8 3 3 g of an ammonium bicarbonate aqueous solution having a stirring concentration of 20% by mass was added to prepare a rare earth carbonate slurry. Use filter paper (No. 5C, Toyo filter paper (strand)) filtered this rare earth carbonate slurry to recover about 197g of solid content. Add pure water to the recovered solid content 1. After stirring for 5 liters, the solid content was recovered by filtering with a filter paper (No. 5C, Toyo filter paper (strand)). This operation is repeated until the pH of the slurry is 6 to 8. The recovered solid content was baked at 1 000 ° C for 1 hour to obtain about 95 g of oxidized rare earths. Table 1 shows the composition of the recovered materials obtained by oxidizing rare earths. Example 3 (Recovery of rare earth oxides) The honing waste liquid having a solid component composition shown in Table 1 was discharged from a honing step of a glass substrate for a hard disk, and the rare earth oxides were recovered in the following order. The honing waste liquid containing 100 g of solid content will be 0.1. 5 liters and 250 g of 35% by mass hydrochloric acid were stored in a flask with a cold water tube, and then heated to maintain the temperature of the solution in the flask at 103 ° C. At this time, the steam generated by heating is liquefied in the cold water pipe and returned to the flask to prevent the liquid level from lowering. After heating for 48 hours, the honing waste liquid becomes a green acid solution containing rare earth chloride, mixed with white silicone, and undissolved materials such as honing pads. -24- (21) 1231805 liquid. After removing the cold water tube from the flask, the mixture was heated and concentrated to half the capacity. After heating and concentrating, the silica gel and undissolved matter float in an acidic aqueous solution containing a rare earth chloride. After that, the concentrated solution was sampled from the flask with filter paper (No. 5C, Adbanteck Toyo filter paper (strand)) filtration, separation and removal of undissolved matter from acidic aqueous solution containing rare earth chloride. After the heating and concentration operation, from the acidic aqueous solution containing rare-earth chlorides, in order to remove most of the silica gel, the filtration and separation time using filter paper was greatly reduced from about 1 hour to about 10 minutes. After heating and concentration operation, almost no acidic aqueous solution containing rare earth chloride contained in the silicone is included. Compared with no heating and concentration operation, the yield of acidic aqueous solution containing rare earth chloride is finally improved from 82% in terms of rare earth oxide conversion 98%. The vapor generated during heating and concentration was introduced into a flask with a cold water tube to liquefy it and recovered with hydrochloric acid. This hydrochloric acid must be reused as a raw material. Dilute the acidic aqueous solution containing rare-earth chlorides recovered by filtration to a total of 1 liter with water, and add 1 65 3 g of an aqueous ammonium bicarbonate solution with a concentration of 10% by mass, and then stir to obtain a white precipitate of rare-earth carbonates. Thing. Use filter paper (No. 5C, Adbanteck Toyo filter paper (strand)) After filtering the aqueous solution containing the precipitate, wash it. The obtained solid matter was stored in a magnetic container, and baked at 1000 ° C in the atmosphere for 1 hour to obtain 98 g of a rare earth oxide. The composition of the obtained rare earth oxide is shown in Table 1. -25- (22) 1231805 Example 4 (recovery of rare earth oxides) The honing waste liquid having a solid component composition shown in Table 1 is discharged from a honing step of a glass substrate for a liquid crystal display (LCD) according to the following Sequential recovery of rare earth oxides. A honing waste liquid containing 100 g of solid content was used. 5 liters and 250 g of 35% by mass hydrochloric acid were stored in a flask with a cold water tube, and heated and maintained at 10 3 ° C. After heating for 48 hours, the honing waste liquid is a mixed solution of green acid solution containing rare earth chloride, white silicon gel, and honing pads. The cold water tube was removed from the flask, and then the mixture was immersed in zeolite and concentrated by heating to reduce the capacity to half. When the mixed solution is heated, zeolite is used as a starting point to generate fine air bubbles, and undissolved substances such as silica gel and honing dust are simultaneously floated on the liquid surface of the solution. After the floating silicone and undissolved, move the inner wall side of the beaker through air bubbles, or reduce the liquid surface to adhere to the inner wall of the beaker through evaporation. The silicone glue adhered to the inner wall of the beaker causes the volume to shrink due to heating through the inner wall of the beaker, and releases the contained acidic aqueous solution containing rare-earth chloride. Without this heating and concentration operation, the yield of the acidic aqueous solution containing rare earth chlorides was 73% in terms of rare earth oxides. After the heating and concentration operation, the yield of the acidic aqueous solution containing rare-earth chloride was increased to 95%. Use filter paper (No. 5C, manufactured by Adbanteck Toyo Filter Paper Co., Ltd.) This concentrated solution is filtered to remove the remaining undissolved matter from the acidic aqueous solution containing rare earth chloride. Using this heating and concentration operation, in order to remove most of the silica gel from the acidic aqueous solution containing rare-earth chlorides, filtering with filter paper -26- (23) 1231805 The separation time was greatly shortened from about 3 hours to about 10 minutes. This rare earth chloride-containing acidic aqueous solution was diluted with water to a 2 liter aqueous solution. Thereafter, 450 g of an oxalic acid aqueous solution having a concentration of 10% by mass was added to the solution, and a white precipitate of a rare earth oxalate was obtained by stirring. Use filter paper (No. 5C, Adbanteck Toyo filter paper (strand)) The aqueous solution containing the precipitate was filtered, and then washed to obtain a precipitate. The obtained precipitate was stored in a magnetic container, and baked at 1000 ° C. for 1 hour in the air to obtain 95 g of a rare earth oxide. The composition of the obtained rare earth oxide is shown in Table 1. Example 5 (Recovery of rare earth oxides) The acidic aqueous solution containing rare earth chlorides obtained in Example 3 was diluted with water to a total of 1 liter of an aqueous solution, and a 10% by mass sodium hydrogen carbonate aqueous solution was added to this solution. 1098 g, followed by stirring to obtain a white precipitate of a rare earth carbonate. Use filter paper (No. 5C, Adbanteck Toyo filter paper (strand) filtered the aqueous solution containing the precipitate, then washed and stored the obtained solid in a magnetic container, and roasted in the air at 1 000 ° C for 1 hour to obtain 92 g of rare earth oxide. The composition of the obtained rare earth oxide is shown in Table 1. Example 6 (Reuse of recovered rare earth oxide honing materials) The method described in Example 5 was repeated using the recovered rare earth oxides to reuse honing materials through the following operations to evaluate the Honing performance. -27- (24) 1231805 (i) After repeatedly adding 5 kg of the rare earth oxide obtained in Example 5 to a slurry with a concentration of 50% by mass, add 150 g of a dispersant (sodium polyacrylate) and subject to high dispersion treatment Machine (ULTRA-TURRAXtm, T50basic, IKA-WERKE) into a slurry. (ii) The medium-type crusher (ball mill) is used for wet crushing, and the wet-type elimination tube is classified to obtain the slurry for honing. As a result of the classification, a small amount of a slurry containing coarse particles not used as a honing slurry and a slurry containing fine particles were obtained. In the next treatment, the slurry containing coarse particles is returned to the crushing step, and the slurry containing fine particles is mixed in the honing material and reused. (iii) Use this honing slurry to carry out the honing process of the glass plate, and extract the honing material at that time. Washing water is used for honing processing, and the solid component concentration of the honing material is 10% by mass. (iv) The honing material is stirred with a blender installed in a polyethylene tank. At the same time, hydrochloric acid having a concentration of 35 to 5% by mass is added to the pH of 5. The mixer is stopped, and the suspended slurry is allowed to settle to remove sediment. The liquid obtained a slurry having a concentration of 28 mass ° / °. (v) this slurry 3. 5kg was placed in a 10-liter glass separable flask. Add 8. 4 kg of 20% by mass of hydrochloric acid. (vi) After the detachable flask is equipped with a cold water pipe and a rod thermometer, a two-square plug is used to form a three-port detachable flask cover, and then placed in a sheathed resistance heater to heat it. The steam generated at this time is returned to the separable flask after being cooled by the cold water pipe. (vii) After heating at a liquid temperature of 120 ° C for 3 hours, connect a 6-liter flask with a bi-directional plug to a cold water tube with a tube, close the cold-water tube of the 10-liter separable flask, and open the bi-directional plug. Vapor was introduced into a 6-liter flask with a cold water tube-28- (25) 1231805 and the remaining hydrochloric acid was recovered by cooling. This hydrochloric acid is used again the next time it is dissolved. (viii) Through this operation, the aqueous solution of chlorinated rare earth in a 10-liter separable flask was concentrated, and undissolved matter and silicone glue were floated and adhered to the inner wall of the container. (i X) After stopping the heating of the sheathed resistance heater, remove the rod thermometer, insert the glass tube into the bottom of the separable flask, and suck in the recovered rare earth chloride aqueous solution. (X) The rare earth chloride aqueous solution obtained by repeating the operations (v) to (ix) described above is filtered with a filter, and ammonium bicarbonate is added to obtain a rare earth carbonate slurry. The solid liquid was separated by a centrifugal dehydrator to obtain a solid of rare earth carbonate. Then, a rare earth oxide is obtained by baking. The composition of the obtained rare earth oxide is shown in Table 1. (26) 1231805
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0CO ooCNi 6CSJTWT (.sls/UIn) ιοΖΌ lozd tozd -33- (30) 1231805 由表2淸楚得知，使用實施例5及實施例6之硏磨材 漿料時，不僅得到與比較例1 一般之硏磨材漿料同等之去 除速度、表面粗糙度，可實現刻痕數產生少之良好的硏磨 表面。 〔發明效果〕 若根據本發明自含有稀土類元素之廢液回收稀土類氧 化物之方法，得自含有稀土類元素，將可再利用作爲硏磨 材等高品質之稀土類氧化物，以簡易之過程，有效爲極高 純度回收之。 -34 -0CO ooCNi 6CSJTWT (.sls / UIn) lozd tozd -33- (30) 1231805 It is clear from Table 2 that when the honing material slurry of Examples 5 and 6 is used, not only is the same as that of Comparative Example 1 The honing material slurry has the same removal speed and surface roughness, and can achieve a good honing surface with a small number of nicks. [Effects of the Invention] If the method for recovering rare earth oxides from a waste liquid containing rare earth elements according to the present invention is obtained from rare earth elements containing rare earth elements, it can be reused as a high quality rare earth oxide such as a honing material. The process is effectively recovered for extremely high purity. -34-