Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
  • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
  • B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
  • B02C23/06—Selection or use of additives to aid disintegrating
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B34/00—Obtaining refractory metals
  • C22B34/10—Obtaining titanium, zirconium or hafnium
  • C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
  • C22B34/1204—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 preliminary treatment of ores or scrap to eliminate non- titanium constituents, e.g. iron, without attacking the titanium constituent

Definitions

• This invention relates to a method for improving the grinding of titaniferous ores and increasing the amount of recovery of titanium dioxide from said ores.
• the first step in the sulfuric acid process for recovery of titanium dioxide from titaniferous ores is to grind the ore to a desired particle size.
• the ore is digested with sulfuric acid to yield a digestion cake which consists essentially of water soluble sulfates of titanium and iron, as well as minor impurities.
• the recovery of titanium can be determined by comparing (a) the titanium assay and weight of the ore to (b) the titanium assay and volume of the resulting solution.
• the sulfuric acid process for preparing titanium dioxide from titaniferous ores is conducted on a large scale and thus, even a small increase in the recovery of titanium dioxide can be commercially important. For example, for a 25 ton batch of titaniferous ore containing 64.6% titanium dioxide, a change in the titanium dioxide recovery from 84.5% to 89% represents a 29% decrease in unrecovered, or wasted titanium dioxide, and 1400 pounds extra titanium dioxide actually recovered. So, any increase in the efficiency of comminution of a titaniferous ore will result in a worthwhile saving even though the unit saving may appear small.
• Canadian Patent No. 962,003 discloses the application of propane diol to pigmentary titanium dioxide, following its preparation by either of the well known sulfuric acid or chloride processes, to improve the dispersibility characteristics of the pigment, particularly in paints; and U.S. Patent No. 3,076,719 describes a treatment of similarly produced titanium dioxide pigment with a polyol of from 4 to 10 carbon atoms which prevents clumping during storage.
• U.S. Patent No. 2,822,241 discloses the addition of a glyceride, particularly a monoglyceride, to a titaniferous ore containing organic flotation agents to improve the digestion of the ore in sulfuric acid.
• the present invention provides as a major object a method whereby the comminution of titaniferous ores may be conducted more efficiently, with the use of certain polyols, so that the recovery of titanium dioxide from said ores upon digestion may be enhanced. Further objects and advantages of the invention will become apparent from the description of the invention which ensues.
• the polyols of the present invention have the formula: R ⁇ C ⁇ (-R'OH) wherein R is alkyl (C 1 -C 4 ), or hydroxyalkyi (C 1 -C 4 ) containing up to 3 hydroxy groups, and wherein R' is alkylene (C 1 -C 3 ).
• R is alkyl (C 1 -C 3 ) and R I is methylene.
• R is ethyl and R' is methylene.
• the polyols are preferably stable and wettable in concentrated sulfuric acid at ambient temperatures (25°C. to 35°C.), but tend to be less stable at the digestion reaction temperature.
• Suitable such compounds include trimethylolpropane, I-hydroxy-2, 2-dimethylolpropane; 1-hydroxy-2,2-dimethylolpentane; 1--hydroxy-3,3-diethylolpentane; 1,3-dihydroxy-2,2-diemthylol- butane, and pentaerythritol.
• the polyol is added to the titaniferous ore in an amount effective to improve the comminution thereof. Generally this amount will be from about 0.005% to about 2% by weight of the ore, desirably from about 0.05% to about 1%, and preferably from about 0.07% to about 0.5%. However, more of the polyol may be added if so desired.
• the comminution is rendered more efficient and the ultimate recovery of titanium dioxide from the ore, upon digestion thereof in sulfuric acid, is enhanced.
• the polyol appears to act as an anti-caking agent for the ore during comminution., resulting in a more rapid reduction of ore particle size.
• the smaller particles are believed to be better wetted by the sulfuric acid, thereby yielding a higher recovery of titanium dioxide.
• the continued presence of the polyol in the sulfuric acid digestion medium apparently further augments the recovery of titanium dioxide from the ore.
• TMP trimethylolpropane
• a 1500 g. sample of the ore was first dried at 110°C. to less than 0.2% water and then placed in a gallon ball jar containing 7500 g. of 1 inch steel balls.
• the ball jar was rotated at 53 rpm for the lengths of time shown in Table I below.
• the ball jar was emptied and the ore particle size determined on a 100 g. sample by sifting in a Tyler Ro-Tap through a bank of sieves ranging from 100 to 325 mesh (Tyler - U.S. Standard) for 30 minutes.
• Table 1 demonstrates that for grind times of 30 minutes and 360 minutes, more -325 mesh particles were produced when TMP in an amount of 0.1% was added to the ore. For this procedure, regular commercially used steel balls, which were not polished, were employed.
• This example shows the improvement in titanium dioxide recovery when a titaniferous ore which was ground using a polyol as a grinding aid is digested with sulfuric acid.
• the method used in this example closely approximates the industrial digestion process, so the results received here are representative of results which would be expected on an industrial scale.
• the end liquor contained about 20% sulfuric acid, and a sufficient quantity was added so that after the valences of all other recoverable sulfatable ore components had been satisfied, there remained enough sulfuric acid to satisfy between 65 and 80% of the titanium valences with sulfate ions.
• the samples were digested in the acid solution at temperatures of about 180-190°C. for about 2 1/2 hours. Thereupon, the resulting digestion cakes were dissolved in water to form a titaniferous liqour which was analyzed for titanium dioxide content, and the results compared with the analysis of the original ore, to determine the titanium dioxide recovery.
• the determination of recovery can be made using any well known method, e.g., reduction of the titanium (IV) to titanium (III) with zinc amalgam and titration of the reduced titanium with ferric ammonium sulfate to a thiocyanate end-point.
• Example 1 The procedure of Example 1 is repeated, except that the trimethylolpropane is replaced by an equal weight amount of l-hydroxy-2,2-dimethylolpropane; I-hydroxy-2,2-di--methylolpentane; 1-hydroxy-3,3-diethylolpentane; 1,3-di--hydroxy-2,2-dimethylolbutane, and pentaerythritol.
• Example 1 The procedure of Example 1 is repeated, except that trimethylolpropane in amounts equal to 0.005%, 0.05%, 0.5%, 1% and 2% is added to the ore.

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• Manufacture And Refinement Of Metals (AREA)
• Inorganic Compounds Of Heavy Metals (AREA)

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Citations (4)

• 1982
  • 1982-02-09 DE DE8282100910T patent/DE3271092D1/de not_active Expired
  • 1982-02-09 EP EP19820100910 patent/EP0085728B1/de not_active Expired

Patent Citations (4)

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