sulfide to the corresponding sulfate. The mercuric sulfate, in turn, interacts with sodium chloride in solution to yield a sodium-mercury tetrachloride complex very soluble in water. Following electrolysis, a separation step removes insoluble waste material from the mercury-pregnant solution. Zinc dust, added to this solution, pre cipitates the mercury, which is finally purified by distillation between 500° and 600° C. In general, the amount of electric power needed to process a ton of ore may fall anywhere between 10 and 50 kwh., depending on the nature of the ore. And the sodium chloride used may be varied from 4% by weight to 10% by weight per ton of ore. Power consumption decreases as the amount of salt used is increased, and vice versa. "In this way you can de sign the procedure around the relative costs of power and salt," Dr. Henrie observes. Another cost variable centers on the type of electrodes involved. The cheaper graphite electrodes can be used if the salt concentration is in the 8 to 10% range. But if salt is ex pensive, iron cathodes and lead diox ide anodes work best for solutions of salt in the lower-concentration range. About half a pound of zinc is lost for every pound of mercury recovered. Dr. Schemer points out that iron, in the form of detined cans, may be used as a mercury-displacing agent. Iron, apart from being cheaper, has the added advantage of not forming an amalgam with mercury. However, mercury plates the iron, reducing its effectiveness and calling for a periodic surface-regenerating step.
TIRES:
Disposal Problem Solved Disposal of worn-out tires has been a problem for years. In this age of pol lution control, the stench and black smoke from burning old tires, the standard method of disposal, is no longer acceptable. Firestone has an answer. By summer's end, the com pany will have in operation a pilot de structive distillation unit at its Akron, Ohio, manufacturing complex to solve the tire disposal problem without "any solid waste, water, or air pollu tion." The process will yield usable chem icals and raw materials for recycling into various manufacturing processes. If the pilot distillation plant proves commercially feasible, Firestone will set up 10 full-scale units across the country. Each plant will be capable of consuming 100,000 tons of scrap tires a year. That's equivalent to about 80 million tires per year for the 12 C&EN JUNE 8, 1970
The destructive distillation proc ess could eventually absorb all the tires scrapped in the U.S., Mr. Laman points out. "The disposal of scrap tires of all types is an ever-increasing national problem. Too many of these scrapped tires are being discarded along the highways and accumulated in unsightly trash piles; worse, large numbers are being burned in open-air dumps, thus contributing to rampant air pollution. This cannot be per mitted to continue. Firestone intends to do its part to help abate air, water, and solid waste pollution. This new process is just one example of our ef forts." m be
DDT:
c
%
Two Against USDA
Κ
Discarded auto tires No more stench and black smoke
10 units, or about two fifths of the tires produced last year. In the process, shredded tires are fed on a continuous basis to a closed thermal reactor where the tires are broken down into gas, liquid, and char phases. About 45% of the tires be come a solid residue, explains Joseph R. Laman, process developer and man ager of environmental engineering for Firestone. "The residue can be used as a filtering medium in tertiary sew age treatment, as a particulate in con crete by the plant industry, or as a smokeless fuel, perhaps in the metal lurgical field as a coke substitute," Mr. Laman says. The 55% gas/liquid fraction con tains about 50 compounds made up of olefins, aromatics, and naphthenes, Mr. Laman says. "The product mix depends on the reactor temperature and can be varied depending on what markets are nearby. They could be used either as fuel or as feedstocks for chemical operations," he explains. Cost figures will be determined from results with the pilot-plant operations, Firestone says. In laboratory tests, totally funded by Firestone, at the U.S. Interior De partment's Bureau of Mines facility in Pittsburgh, up to 140 gallons of oils and 1500 cu. ft. of gas were obtained per ton of scrap tires distilled. The gas has a heating value of 800 to 1200 B.t.u., which is comparable to the heating value of natural gas. The batch laboratory process used at the Bureau of Mines will be upgraded to an automated, continuous process when scaled up for the pilot plant and full-scale units.
Environmentalists have won the latest two rounds in the legal bout over a D D T ban. One of two decisions 11 days ago by the U.S. Court of Appeals for the District of Columbia orders Agriculture Department action late this month; the other renews the con troversy over no D D T residues on foods. What's more, the first ruling opens the door to more court chal lenges by environmentalists on deci sions on other pesticides by the De partment of Agriculture. Ruling for a conservationist coali tion led by the Environmental Defense Fund, Chief Judge David L. Bazelon threw out Agriculture's arguments against a petition to cancel or suspend D D T uses. Secretary Clifford M. Hardin will have to suspend all D D T registrations for interstate shipment or tell the court, in detail, the reasons for "his silent but effective refusal" to do so. Late last year, USDA an nounced a phase-out of D D T by 1971, canceled D D T registrations of 35% of the already dwindling D D T market— which was appealed by seven firms, now down to four—and called for com ment. A report is expected soon on the 3000 comments generated. In the E D F case, USDA argued that only those who register pesticides can contest its decisions. Judge Baze lon struck down this interpretation, stating that either individuals or groups like E D F can challenge USDA decisions. E D F lawyers sug gest this will lead to more court suits. A USDA spokesman says that there is "no question" but that this will hap pen. The question of D D T on foods is open again after Circuit Court Judge J. Skelly Wright ordered Health, Ed ucation, and Welfare—over the De partment's objection—to publish a pro posal for zero tolerances of D D T in or on raw agricultural commodities. Five mothers (who claimed that breast
THE CHEMICAL WORLD THIS WEEK
milk contains D D T residues twice the level considered safe by the World Health Organization), an agricultural worker, and E D F made the proposal, since modified to exempt residues ap plied before a tolerance would be set. Judge Wright called this "one possible solution" while recognizing that a zero tolerance set immediately would be an "infeasible, major disruption" of the U.S. food supply. At press time, De partment of Health, Education, and Welfare officials were uncertain what action they would take.
DESALINATION:
Pure Water by Magnetism A magnetic method has been added to evaporation and reverse osmosis technology for desalination. The new method, developed by Dominic Avampato, depends on concentrating ions in certain regions by use of a magnetic field, followed by removal of relatively purer water in the remain ing region. At first it might seem obvious that the method would work since ions are affected by magnetic fields. It might seem just as obvious, though, that it couldn't work, since charge shield ing by solvent weakness of external magnetic fields and stirring effects would wipe out any gains. To Mr. Avampato of State University of New York, Farmingdale, the important things are that it does indeed work, that he holds U.S. Patent 3,511,776 on the process, and that he expects an agreement this week with Research Corp. of New York City on commer cialization. The simplest device built by the SUNY chemist channels water through a pipe past an ultraviolet or x-ray source. He thinks that the radiation ionizes ions in the water to higher oxi dation states. Sodium might be mo
mentarily ionized to the + 2 oxidation state, magnesium and calcium to + 3 , and halogens to + 1 . The water next flows past a magnet (see illustration), which deflects the ions away from the center of the pipe. With the cen tral region of the pipe relatively de pleted of ions, water in this region flows into an inner pipe and out of the apparatus. Analyzing by titrations and MC1 labeling, Mr. Avampato says he aver ages 15% removal of ions from 3.5% sodium chloride solution with an ex trapolated flow rate of 33 gallons per minute. Removal of 92% of ions has occasionally been attained. The purer water from the central region can easily be processed in another unit, Mr. Avampato thinks, and he has designed a multistage unit which will channel high and low ion concentra tions from each step to the appropriate imput cycle of another chamber. Magnetic field strength has to be matched to radiation energy, he finds. He switched from electromagnets to permanent magnets when required field strength was known. Thus the only required power would involve the ultraviolet or x-ray source. He finds some regions of water in the main pipe rich in hydrochloric acid and others rich in sodium hy droxide. He thus envisions a possi ble separation of chemicals from sea water or brines by the same method. In a world short of lone pioneers, Mr. Avampato has reached the com mercialization stage of his process at his own expense and in his basement. He comes to Research Corp. with a patent obtained on his own. Says Dr. Willard Marcy of Research Corp., "It will be at least a year or two before pilot-plant production will even begin. At the present stage of development, no cost study is pos sible." Mr. Avampato turned to the corpo ration to solve difficulties of suitable commercialization of his invention.
With power requirements of the tech nique an unknown quantity, it remains to be seen whether magnetic methods will buck evaporation or reverse os mosis technology, but in the next two years Mr. Avampato expects to learn the answer.
ACS:
Pension Plan Go-Ahead ACS's proposed and much talked about professionwide pension plan has re ceived an official go-ahead from the Society's Board of Directors. Meet ing at a special session held during the Joint Chemical Institute of Can ada-AC S Conference in Toronto, the Board voted without dissent to ap prove the recommendation of the So ciety's Committee on Profession-Wide Pension Plan (PWPP) already en dorsed by the Council in February. The recommendation calls for es tablishment of an independent entity for the purpose of implementing a professionwide pension plan and a loan from ACS not to exceed $105,000 to be used to cover initial ex penses in setting up the plan. Details of the proposed expenditures were specified in a letter from Dr. Ε. Ε. McSweeney, chairman of the PWPP Committee, to ACS Board Chairman Milton Harris. "I know Dr. Mc Sweeney and those working with him on this very timely matter will do all in their power to bring the plan into being at the earliest possible date," Dr. Harris said in a letter announc ing the Board's action to the Society's nearly 900 councilors and alternate councilors. The entity to be established will consist of a new separate organization which will be a trust or corporation, having as its board of directors desig nated representatives from several ma jor scientific and professional societies in the U.S. This corporation or trust will not be under the control of ACS, although some ACS members will be on the plan's board of directors. The ACS Board action granted au thority for making appointments to PWPP's governing body to Dr. Harris, who will do so in consultation with Society President Byron Riegel and ACS Executive Director F. T. Wall. PWPP has been under intensive study by ACS for several years. It was formally presented to the ACS Board of Directors in February and to the members in March (C&EN, March 9, page I S ) . Before sanctioning So ciety efforts to create a national porta ble pension system, the ACS Board wanted to be sure that members un derstood the plan's limitations as well as its benefits with respect to such points as eligibility and portability. JUNE 8, 1970 C&EN
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