专利类型:  发明专利
申请号:  US27343988
申请日期:  1988-11-17
公开号:  US5068093A
公开日期:  1991-11-26
申请人:  ESCHER WYSS AG
发明人:  MAUER JOSEF
地址:  
摘要:  Titanium slag and ilmenite are subjected to a parallel treatment with sulphuric acid obtained by mixing different proportions of sulphuric acid having concentrations of about 98.5% by weight and about 85% by weight, respectively. The reaction mixtures have a temperature slightly below a predetermined starting temperature and the reactions are started by adding small quantities of superheated steam having a temperature above the predetermined starting temperature. The thus obtained solutions are separated from the respective treatment residues and combined. The combined solutions are further processed for obtaining titanium dioxide. The mother liquor constitutes sulphuric acid of a concentration in the range of about 23% by weight and containing metal sulphates. This mother liquor is concentrated to a sulphuric acid concentration of approximately 85% by weight and recycled. The obtained metal sulphates are roasted and the roast gases further processed to obtain highly concentrated sulphuric acid which is recycled to the titanium slag treatment whereas the excess recycled about 85% sulphuric acid constitutes the main component used for the ilmenite treatment. The weak acid obtained from the mother liquor thus is almost entirely re-used in an economical manner.
主权项:  A method of producing titanium dioxide, comprising the steps of: (1) selecting titanium slag and ilmenite as titanium-containing starting materials in a defined ratio; (2) during a parallel treatment, reacting said titanium slag with sulphuric acid and separately reacting said ilmenite with sulphuric acid; (3) said step of reacting said titanium slag during said parallel treatment with the sulphuric acid entailing the steps of: (i) mixing said titanium slag with highly concentrated sulphuric acid having a concentration of at least 95% by weight; (ii) adding to the thus obtained mixture, less concentrated sulphuric acid having a concentration in a range of 76% by weight to 87% by weight; (iii) reacting said mixture containing said added less concentrated sulphuric acid and thereby obtaining a titanium-containing solution; (iv) separating said titanium-containing solution from a titanium slag treatment residue; (4) said step of reacting said ilmenite with sulphuric acid during said parallel treatment entailing the steps of: (i) mixing said ilmenite with highly concentrated sulphuric acid having a concentration of at least 95% by weight; (ii) adding to the thus obtained mixture, less concentrated sulphuric acid having a concentration in a range of 76% by weight to 98% by weight; (iii) reacting said mixture containing said added less concentrated sulphuric acid and thereby obtaining a titanium-containing solution; (iv) separating said titanium-containing solution from an ilmenite treatment residue; (5) combining the titanium-containing solutions separated from said titanium slag treatment residue and said ilmenite treatment residue; (6) hydrolysing the thus obtained combined titanium-containing solutions and thereby obtaining a titanium-containing hydrolysis product and a other liquor constituting a metal sulphate containing dilute sulphuric acid; (7) separating said titanium-containing hydrolysis product from said mother liquor; (8) recovering titanium dioxide from said titanium-containing hydrolysis product; (9) concentrating said mother liquor and thereby recovering sulphuric acid having a concentration in the range of 76% by weight to 87% by weight; (10) during said step of concentrating said mother liquor, separating metal sulphates from said mother liquor; (11) recycling said recovered sulphuric acid having said concentration in the range of 76% by weight to 87% by weight into said parallel treatment and (i) utilizing part of said recovered sulphuric acid during said step of adding said sulphuric acid having said concentration in the range of 76% by weight to 87% by weight to said mixture of titanium slag and highly concentrated sulphuric acid having a concentration of at least 95% by weight; (ii) utilizing a further part of said recovered sulphuric acid during said step of adding said sulphuric acid having said concentration in the range of 76% by weight to 87% by weight to said mixture of ilmenite and highly concentrated sulphuric acid having a concentration of at least 95% by weight; (12) during said parallel treatment, utilizing as a starting condition for reacting said titanium slag (i) a temperature of about 120° C. and (ii) a ratio of said highly concentrated sulphuric acid having a concentration of at least 95% by weight and said recovered and recycled sulphuric acid having a concentration in the range of 76% by weight to 87% by weight which results in a total sulphuric acid concentration of about 90% by weight; and (13) during said parallel treatment, utilizing as a starting condition for reacting said ilmenite (i) a temperature of about 90° C. and (ii) a ratio of said highly concentrated sulphuric acid having a concentration of at least 95% by weight and said recovered and recycled sulphuric acid having a concentration in the range of 76% by weight to 87% by weight which results in a total sulphuric acid concentration of about 85% by weight.
专利分类号:  C01G23/053;C22B34/12;C01G23/04(5)
专利状态:  失效专利
代理人:  
代理机构:  Sandler, Greenblum & Bernstein
国家及地区:  
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