low concentration i e a primary cu ore body the range of trithiocarbonate used can be from about 0 1 to 5 pounds per ton of concentrate in one preferred embodiment of the instant invention carboxyalkyl trithiocarbonates are used to suppress the flotation of cu fe and 34 insols 34 ca and mg silicates in the presence of molybdenum the molybdenum bearing minerals found in these ores include such substances as molybdenite mos 2 and wulfenite pdmoo 4 these and other molybdenum containing materials can be isolated from the minerals containing froth while the flotation of the less desirable minerals is suppressed by the reagents of the invention any froth flotation apparatus can be used in this invention the most commonly used commercial flotation machines are the agitair galigher co denver d 2 denver equipment co and the fagergren western machinery co smaller laboratory scale apparatus such as the halimond cell can also be used the instant invention was demonstrated in tests conducted at ambient room temperature and atmospheric pressure however any temperature or pressure generally employed by those skilled in the art is within the scope of this invention the following examples serve to illustrate the operability of this invention this example describes the preparation of the hydroxy and carboxyalkyl trithiocarbonates described herein this procedure is typical for all compounds prepared to a 3 neck glass flask fitted with a condenser stirrer thermometer and dropping funnel was added 180 milliliters of water and 42 grams 1 05 moles of sodium hydroxide after cooling to below 50 u00b0 c 53 grams 0 5 moles of 3 mercaptopropionic acid was slowly added with stirring over a 20 minute period the mixture was cooled to below 45 u00b0 c whereupon 38 grams 0 5 mole of carbon disulfide was slowly added over.