US 2437164 A
Description (OCR text may contain errors)
anclonly a minimum;of'agitation is required-(10 Patented Mar. 2, 1 948 M TFFI n in sec s rarest escalate 2,437,164 PROCESSING OF TITANIUM "ORES Edward N, Kramer;WilmingtomriDelg 'assi'gno'r to E1. ldu 'Pont? de. Nemours"& Gompany, :Wih
mington, Deli; a, corporation of Delaware 1 No Drawing. Application December 8; 1944; Serial-No. 567,327
4 Claims? (01. 23-117) This invention relates to animprovementin titaniumicontentrtotlsoluble titanium sulfate is the processing of titanium ores and morepartic well =knownm Thus, zwhereas' on1y.zabouts%- of ularly to the comminution.ofcilmenite to pro- Indianzilmeniteibecomes:solubilizedwhen treated" mote its reactivity with acids in the extraction of in: the :ungrQundstateWith' sulfuric acid; about." titanium values therefrom." 5 95% :is solubilized when the fore has been :previ- In 'the production of titanium'exide' pigments ouslyrground v:to a :fineness in rexcesswof: 90% from titaniuim o-ressuch as ihnenite'; the ore 'is through fi25'fmeshiscreen.s' Further increases in converted to soluhle titanium and iron'salts'by the" conversion: result upon decrease inithes325 acidattack', followed"by extraction' Of 'suchsalts mesh screen'rresiduesf .An'..increaseamounting to with the aid of water or'dililt'e acid-solutions. -abouti2%is obtainedwh'en th'efinenesshas been Titanium ores most generally usecl in such'pigincreased-.irom-:91*to 97% thrcugha -325.mesh ment manufacture comprise -be'ach sand*Indian screem: i1 e ite;-an 1y i g areund60% TiOaanci- When-teroundailmeniteis sulfateci, it is usually; ofirona Asi's known; this ihnenitesand maybe groundiinfthe' drsteonditionandiwithlthetaidlof reacted-withsulfuricacid to form iron and titdair-segaratihg equipment: The reduction:imill-v niurn sulfatesyeither before or after-'grinding'of maycomprise a tubef-smill, 'ringr-rollimi'l'l, or a ball:
the ore to a fine condition. The'ungr und-ore mill type. These mills are ordinaril sweptwith:
is lesseasilyattacketl by the acid and iaccordirigly ai to draw 'off; the fines whil'e theicoarseimate- EXCESS quaintii so acid m st 'bfi used o flbta n rial remains toibe retreatsd andf further 'commi-n satisfactory" acidsconversicn; The =acid=is' the::2 utedtin the: milL The associated air -separation molv'expenslvei reagent 'eXCeSS H2501 is not satisfactorily eflicienthecause .the' groundcannot be separated iromth'e soluble salts, whi1 product-"'flo'cculates'. Addition of ordinary air any. eXcess-of'iimenite:canibe readily removed-due p r ing agent use has not b'e'en re t to to its solid character. Hence, the industry has endeavored to obtain highconversion of acid even cause of the danger of-snbsequent solution" 01" final-product contamination-z" Good dispersion of though saclfififie cPnvel'smn Of Hmenit'e the ground pro-duct in air is essential to highest resulted. ThlS- 1s sushfied bsr bothecq m efficiency-"and'the"recovered'product Inust'beeasph i 'conslde,ratlons' acid content ily dispersed in sulfuric'acid; without "any'impairof the resulting-solutions may be IIICZBZIS BCI Wl'IGII"; ment. Grits reactivity ccmammation of the the'solut ons are founo defi tf m? solution resulting" from the'sulfation; In other to z 'emoye any x i f f h I words',ithe"grindin'g'effi'ciency 'hasbeen somewhat dust-ry. takes advantage of this by-norma11y-car- 10w randundesimmy impaired? reason ofthe rying out the sulfating operation in the presence of a slight'excess of ilmenite in order that th'e acidity of the sulfatemixed will be slightly lower thanis desirable inzthesolution WbiCh'I'is later tot: he prepared for-hydrolysis; The extent of :the: .t excess'rtof. ilmenite has been found todepend largely on the fineness of'thefore.
The sulfate reaction is most easily carried out r40 when the ilmenite .is in-finelygroundmondition and suspension difiiculties are not encountered 2' during the course of thereactioni Finelydividar ed ilmenite is readily suspended :insulfuric acid flocculation'of the'finely-ground material which a heavy load upon the millhy' virtue ofpoor separation of the fines.
overcome-the above and other disadvantages which. characterize prior titatniferous oregrindin'gioperations, and to provide a novel method for occurs during air separation. This has caused It is among the..obj-ects of i this invention. .tov
attaining.suchliobjects. A salient. object v.is .to overcome thelflocculat'ion of ilmenite during its. particle "size reduction and to increase the effie'i ciencylof .ilnienite. dry grindin andair separa.-.
maintain-a uniform Suspension up to during. tion operations. Further objects are to decrease the course of the reaction to form -the solnble D pQ D p p ironandtitanium sulfates. This decrease of agie ration Ufa finelyeg'rwnd ilmenille f given fi tation. requirements has; reduced plant insta11a-- 11885 ificationito increasethe capa y a tion costs for theacid attack and thesaving.- given D t y C S- g tkeffic ency c t-grind effectedhas justified the installationof grinding and separation equipment employed therein ingequipmentfor the ore. The increased cons through the additionof-a dispersing as t Whifih version of the ilmenite also has been a stron con will have no-bad ornndesired effect 111 tributing factor inrestoring to ilmenite-grincling. sequent iprocessing operationsner contaminate The effect of ore fineness on conversion -of.its !-.55 =-the solutions or final TiOz pigment 1'eS uIting therefrom. Other objects and advantages will be evident from the ensuing description of the invention.
The above and other objects are attainable in this invention which broadly comprises effecting the particle size reduction and subsequent separation of the ground particles of a titaniferous ore in the presence of a'small amount of naphthenic acid.
In a more specific and preferred embodiment, the invention comprises adding to beach sand Indian ilmenite from about .02% to .2%, on the ore basis, of naphthenic acid during the introduction of the ilmenite into a dry grinding mill equipped with an air separator together with means for recirculating the coarser ore fractions, and effecting the subsequent ore reduction and air separation of the ground particles in the presence of the naphthenic acid so added.
In practically adapting the invention, the basic ore, Indian ilmenite, in the form of small pebbles or a sand consisting of particles in excess of about 40 mesh is fed to a conical ball mill equipped with an air classifier system, e. g., is air swept to remove finely-ground material and this air-borne dust is removed to a separator system of the usual type where the fines are collected as by use of a cyclone, the coarse materials being returned to the mill for further grinding. In order to improve and promote the grinding or classification, or both, a small amount of naphthenic acid, say, about .05 to .15%, is added to the ore as it is fed to the mill. By reason of such treatment, the production rate becomes increased without any sacrifice in fineness, and, if desired, the fineness can be increased without any sacrifice in the production rate.
Naphthenic acid use in this system has been found to be unique in its behavior since it fulfills the requirements of an air dispersing agent and yet is not injurious to and does not impair the preparation of hydrolyzable titanium sulfate so lutions nor affect the final TiOz product from the finely-ground ore containing the reagent. As already mentioned, the treated ore must readily disperse in air and also in sulfuric acid. Other reagents such as those of the oleic acid type when used in the system, though useful in promoting grinding efficiency, provide a treated ore which cannot be readily wetted with the sulfuric acid and hence an undesired impairment of conversion results. This decreased conversion nullifies the eifect of the increased fineness and accordingly the objects of this invention are not realized when such other agents are used as dispersing or grinding aids.
The term naphthenic acid, as used herein, refers to cycloparaflinic carboxylic acids as found particularly in various petroleum oils. They may be extracted from these oils or distillates thereof by processes well known in the art, such as by treatment of the oils or their distillates with aqueous sodium hydroxide solutions in which the acids dissolve yielding sodium salts. The lyes from this treatment are acidified, thereby yielding considerable amounts of free cycloparafiinic carboxylic acids. It is understood, however, that this method of recovery of the naphthenic acid material is not essential to the present process and is given only as a method for its recovery and to identify the material.
To a clearer understanding of the invention, the following specific examples are given, none of which is to be considered as limiting the invention:
4 Example I Indian beach sand ilmenite was ground in a conical ball mill containing steel balls and equipped with a superfine air classifier at a rate of 5.5 tons per hour and with classifier and fine damper sets adjusted to give a top product size of 93% through 325 mesh. Experience had shown that such conditions gave the optimum mill load, which in this case was 250-260 kilowatts on the motor.
Naphthenc acid, to the extent of 2 pounds per ton of ore going to the mill, was added to the mill feed with no other change being made in the system. The throughput of the mill was then found to be 8.2 tons per hour or an increase in mill capacity of about 50%. The resulting naphthenic acid-treated ilmenite was then tested for attackability with sulfuric acid. It was found to be readily wetted by the acid and that the titanium content of the ore converted readily to soluble titanium sulfate when treated in the usual manner of attack.
Example 11 Indian beach sand ilmenite was ground in a conical ball mill containing steel balls and equipped with a superfine air classifier at a rate of 8.0 tons/hour and with a classifier and fine damper sets adjusted to give a top product size of 87% through 325 mesh.
Naphthenic acid, to the extent of of the ore, was added to the mill feed. In addition the mill was adjusted to give increased fineness by means of a change in the air damper setting to give a fineness of 93% through a 325 mesh screen while maintaining the optimum mill load. The grinding rate under these conditions was found to be 8.2 tons an hour Which is slightly better than that found using no naphthenic acid. This production gave increased conversion of the ilmenite upon treatment with sulphuric acid as compared with the untreated production. This increased conversion to the soluble condition amounts to about 2%.
Example III To the mill of Example I was fed the same ilmenite, together with l# naphthenic acid/ton of ore. In addition the mill was adjusted to give increased fineness by means of a change in the air damper setting to give a fineness of 97.2% through a 325 mesh screen while maintaining the optimum mill load. The grinding rate under these conditions was found to be 6 tons/hour which is approximately a 10% increase in capacity over that found when using no naphthenic acid. This increase in fineness along with a considerable increase in capacity shows the effectiveness of naphthenic acid even in amounts as low as lit/ton of ore.
While the invention has been described as applied to certain specific embodiments thereof, obviously it is not limited thereto. For example, while particularly adaptable to Indian ilmenite treatment, it is also applicable to the treatment of all types of titaniferous ores, including the various ilmenite, rutile and brookite forms.
Similarly, though especially useful in the treatment of titaniferous ores preparatory to their sulfuric acid attack and sulfation, the contemplated naphthenic acid treatment is also effective and beneficial prior to the attacking or digesting of the ore with other mineral acids (hydrochloric, nitric) to obtain titanium chloride or nitrate solutions, etc.
I claim as my invention:
1. A process for converting a titaniferous ore to water-soluble state, comprising subjecting said ore to comminution, air classification, and reaction with a mineral acid, in the presence of a small amount of a naphthenic acid dispersing agent consisting of naphthenic acids derived from petroleum oils, said agent being adapted to disperse said ore in air and said mineral acid.
2. A process for converting a titaniferous ore to water-soluble state, comprising subjecting said ore to comminution, air classification, and reaction with a mineral acid, in the presence of from .02% to .2%, 0n the ore basis, of a naphthenic acid dispersing agent consisting of naphthenic acids derived from petroleum oils, said agent being adapted to disperse said ore in air and said mineral acid.
3. A process for converting beach sand Indian ilmenite t0 water-soluble state which comprises subjecting said ilmenite to comminution, air classification, and reaction with a mineral acid, in
the presence of from .02% to 2%, on the ilmenite basis, of a naphthenic acid dispersing agent consisting of naphthenic acids derived from petroleum oils, said agent being adapted to disperse said ilmenite in air and said mineral acid.
6 4. A process for improving the grinding and air classification of beach sand Indian ilmenite preparatory to its acid attack to form soluble titanium compounds therefrom, which comprises mixing on the ilmenite basis about .02% to .2%
of naphthenic acid with said ilmenite while the latter is being fed to a dry grinding mill equipped with an air separator, efiecting the comminution and air separation of said ilmenite 1n the presence of said naphthenic acid consisting of naphthenic acids derived from petroleum oils, and thereafter reacting the comminuted naphthenic acid-containing ilmenite with sulfuric acid to convert said ilmenite to water-soluble titanium and iron sulfates.
EDWARD N. KRAMER.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,752,902 Famer Apr. 1, 1930 1,985,076 Breyer Dec. 18, 1934 1,986,301 Stockton Jan. 1, 1935 7 2,274,521 Berry Feb. 24, 1942