Dust Treatment Research Articles

最近の四阪工場におけるＥＡＦダスト処理について

最近の四阪工場におけるＥＡＦダスト処理について

MFプロセスによる電炉ダスト処理

MFプロセスによる電炉ダスト処理

Treatment of Electric Arc Furnace Dust With a Sustained Shockwave Plasma Reactor

In the reprocessing of steel from automotive scrap, lead, cadmium and zinc, which are volatile constituents, vaporize under the extremely high localized temperatures in an electric arc furnace at the points of contact between the graphite electrodes and the charge. These vapors condense to produce a hazardous dust termed electric arc furnace dust (EFD). This study was undertaken to satisfy the need for a mobile system which could be moved from site to site of generators of EFD to avoid transportation of hazardous waste, and to recycle slags and metallic iron products within the plant. A new type of plasma device, the Sustained Shockwave Plasma (SSP) has been developed and tested for treatment of EFD on a laboratory scale (500 g h-1). Batch tests show that EFD can be treated to produce a non-hazardous slag and metallic zinc and lead to recycle.

Ammonium carbonate leaching of carbon steelmaking dust. detoxification potential and economic feasibility of a conceptual process

Dumping of untreated dust generated during electric arc furnace (EAF) carbon steelmaking is nowadays regarded as hazardous practice. This is due to the presence in the material of toxic species leachable under mildly acidic conditions. The use of ammoniacal ammonium carbonate (AAC) leaching for the treatment of EAF dust has been investigated on a laboratory scale and is reported in this paper. The experiments were conducted on dust samples from three European companies. As received, the dusts were found to be toxic when tested according to current US Environmental Protection Agency (EPA) toxicity testing procedures. Toxicity was on account of the leachability of one or more of the following: Ag, Hg, Pb, and Cd. For the three dust samples, it has been found that AAC leaching is able to rapidly solubilize the contained free zinc oxide to yield non-toxic residues according to EPA criteria. On the basis of the bench scale results obtained, a process is proposed for the treatment of EAF dust by AAC leaching. A preliminary economic appraisal of the proposed process is presented which indicates that AAC leaching has a potential of being a competitive alternative to current dust treatment technologies.

Application of iron-oxidizing bacteria to hydrometallurgical flue dust treatment and H2S desulfurization

Flue dust produced from the Kosaka copper flashsmelting furnace contains metals such as Cu, Pb, Zn, Fc, As, Cd, etc. To recover these metals, the dust is treated in the hydrometallurgical plant. Previous iron oxidation by air blown at pH 5 and at 50°C for removal of iron from the leached solution has been superceded by bacterial iron oxidation and pecipitation processes. The advantages of this bacterial oxidation procedure are (i) low cost; (ii) clear separation of metals; (iii) improvement in settling and dewatering characteristics and smaller, stable of volume precipitate and (iv) possibilities of fixing arsenate to obtain inexpensive ferric ions. A new hydrogen sulfide gas treatment process has been developed to treat the gas from plants producing barium chemicals. Itydrogen sulfide (70% content) is absorbed on ferric iron solution, and is thus oxidized to elemental sulfur. After the sulfur has been separated, the iron- oxidizing bacteria are employed to regenerate the absorbing solution. In this plant, which produces 150 tons sulfur per month, the hydrogen sulfide content of sweet gas is kept under 10 ppm; equivalent to 99.99%,; of the hydrogen sulfide recovery. The advantages of this process are (i) high H 2S gas removal efficiency; (ii) low running cost; (iii) ease of operation and maintenance: (iv) no waste; (v) high H2S selectivity; and (vi) good flexibility overload fluctuations.

Application of iron-oxidizing bacteria to hydrometallurgical flue dust treatment and H2S desulfurization

Application of iron-oxidizing bacteria to hydrometallurgical flue dust treatment and H2S desulfurization

電炉ダストの新処理法

From Electric Furnace Dusts (E F Dusts), that are not always entirely treated through nonferrous-metals refining companies, only Zinc element is recovered and Ferrous element wasted in vain. In this paper, author proposed a new process of E F Dust treatment which not only remove Zn and Pb but upgrade Fe content by chlorinizing and reduction roasting, on addition of ferrous chloride converted from limonite, ferric or ferrous hydrate, active ferric or ferrous oxide etc, on waste gas treating stage.Thus in this process the treated products are able to reuse as feed materials to electric furnace.

都市ごみの収集計画支援システムの開発とその応用

This study aims to develope a computer aided planning system for refuse collection. This system consists of data base system of detailed streets network, estimation models of refuse quantity and collecting hours, and programming model for optimal vehicle schedule planning. As applications of this system, this paper shows the examples of appropriate vehicle schedule plan from the view point of equalization of labor load on every vehicle, and estimates effects on reduction of collecting time by introducing large type dust carts, separate collection and treatment of noncombustible refuse.

Ｔｈｉｏｂａｃｉｌｌｕｓ ｆｅｒｒｏｏｘｉｄａｎｓの鉄酸化活性に及ぼす銀イオンの影響

Effect of silver ions on iron-oxidizing activity of Thiobacillus ferrooxidans was investigated in order to examine the application of T. ferrooxidans in the leaching of silver sulfide.The 6 strains of T. ferrooxidans used in this study were isolated from process waters of mine water treatment plants, a H2S gas treatment plant and a flue dust treatment plant utilizing T. ferrooxidans, and drainage waters of sulfide mineral mines in Japan.Silver ions inhibited iron-oxidizing activity of T. ferrooxidans. Oxidation rate decreased as silver concentration was increased. Critical silver concentrations at which each strain used could oxidize more than 90% of ferrous ions (initial concentration 4.0×10-2 mol/l) were from 0.10m/g to 0.28mg/l. Addition of copper ions revived iron-oxidizing activity of T. ferrooxidans that was inhibited by silver ions. A Copper tolerant strain cultured in the mediums with gradually increasing copper concentration up to 13g/l had higher silver tolerance. The strain oxidized more than 90% of ferrous ions at the silver concentration of 1.04mg/l. A nickel tolerant strain cultured in the mediums with gradually increasing nickel concentration up to 10 g/l had less silver tolerance.

Combined hydrometallurgical treatment of copper smelter dust and lead smelter copper dross

At the Naoshima Smelter and Refinery, the copper smelter precipitator dust (EP dust) from the Mitsubishi process has been treated by sulfuric acid leaching for impurities bleed-off. The requirement to treat, in addition, copper dross from a lead smelter arose recently. Consequently, the behavior of copper dross during acid leaching was studied to determine whether a combined treatment was possible.Laboratory tests showed that about 80% of the copper in the dross could be extracted under the following conditions: 80°C; input sulfuric acid concentration of 200 kg/m3; 150 kg solid/m3; and 4–6 h under oxidizing conditions. In comparison, leaching of the copper smelter dust is relatively easy. Leaching can be conducted at a higher pulp density, a lower acid concentration, and a shorter retention time.Assuming a batch treatment, the combined treatment is possible by charging the dust to the dross leaching tank near the end of dross leaching. The overall plant size can be almost the same as is required just for dross leaching. The leach residue is recycled to the lead operation. Copper and cadmium are recovered from the solution by neutralization and cementation, respectively. The final solution is sent to the wastewater treatment plant. The combined treatment significantly reduces the operating costs compared to the individual treatment. The plant with a capacity to treat 300 t/month of dust and 200 t/month of dross is under construction and will start operation in 1992.

A hydrometallurgical process to treat carbon steel electric arc furnace dust

A process is described for the treatment of carbon steel electric arc furnace dust to remove zinc, lead, copper and cadmium as sulphides, potentially saleable to a zinc plant, followed by recycling of the iron oxide residue to the steel producing furnace. Clean gypsum, expected to be saleable, is a by-product. The process uses a strong acetic acid leach to dissolve most of the heavy metals and calcium. hydrogen sulphide to precipitate the heavy metal sulphides, and sulphuric acid to precipitate calcium as gypsum. The regenerated acetic acid is treated by ion exchange to remove impurities. The acetic acid is reconcentrated by distillation or other means for recycle to strong acid leaching.

A comparison of dust and acetone infusion applications of tolclofos-methyl to bean seeds for the control of Rhizoctonia solani

Treatment of bean (Phaseolus vulgaris) seeds with tolelofos-methyl reduced pre-emergence mortality and hypocotyl rot caused by Rhizoctonia solani. The fungicide was effective when applied either as a dust treatment or by infusion in acetone solution. Neither the acetone infusion nor the dust application had any adverse effects on the germination of seeds sown in uninfested soil. Acetone infusion was effective after short periods of immersion (1 min) and with repeated use of the same solution, thus resulting in more efficient use of the fungicide. Both methods of fungicide application effectively controlled rhizoctonia diseases in the field.

Response of Eastern and Formosan Subterranean Termites (Isoptera: Rhinotermitidae) to Borate Dust and Soil Treatments

Workers of the termites Coptotermes formosanus Shiraki and Reticulitermes flavipes (Kollar) were topically treated with disodium octaborate tetrahydrate, a fine-grain zinc borate, or boric acid (+1% magnesium stearate) powder; they were also exposed to sand treated with borates in an indirect exposure tunneling assay. Dust treatment with boric acid powder caused the most rapid mortality, with application of all three powders causing 100% mortality within 15d. Treatment of 10-20% of the termite workers in test groups with borate dusts indicated that the toxicants are transmitted by grooming or trophallaxis (or both) to untreated individuals. However, less mortality occurred in groups of C. formosanus than in corresponding groups of R. flavipes workers when 10% of the workers were treated with disodium octaborate tetrahydrate or zinc borate powders. Both termite species readily penetrated sand containing 5,000, 10,000, or 15,000 ppm disodium octaborate tetrahydrate or zinc borate. In the 10-d test period, ≥5,000 ppm (or greater) disodium octaborate tetra hydrate and 15,000 ppm zinc borate in the sand elicited high mortality (85-93%) in R. fla vipers . Responsesof C. formosanus workers were more variable. Only 10,000 and 15,000ppm zinc borate in the sand caused mortality (70-89%) significantly different from that in control groups. In both dust transmission and tunneling experiments, interspecific differences in grooming or tunneling behavior may cause reduced exposure of C. formosanus to the borates.

R&D opportunities for pressure hydrometallurgy

The opportunities for pressure hydrometallurgy remain bright. New processes remain to be developed in the areas of sulfide pressure leaching, laterite/oxide treatment and in the environmental area of metallurgical dust treatment. Careful fundamental studies combined with technical development along a variety of fronts should result in the anticipated breakthroughs.

The processing of steelmaking flue-dust: A review

This review paper surveys technologies that are in use for processing steemaking flue-dust. Four categories of dust have been identified and used in the discussion, namely: carbon steelmaking dusts with a high, low, and intermediate non-ferrous metal content, and dust obtained from stainless steelmaking. Adequate technology is found to be lacking for carbon steelmaking flue-dust with an intermediate non-ferrous metal content. The paper also considers the better known ideas which have been proposed, either as alternatives, or as complementary aspects to existing dust treatment options. The advantages and disadvantages of all examined dust treatment processes are highlighted. In addition, the paper contains sufficient information for an appreciation of the steel industry's flue-dust problem.

Effectiveness of cyfluthrin dust treatment for control and protection of shelled maize against infestation by the larger grain borer,Prostephanus truncatus(Horn) (Coleoptera: Bostrichidae) in Tanzania

Abstract Knockdown, mortality and residual activity of pyrethrins and cyfluthrin were studied on the larger grain borer (LGB), Prostephanus truncatus (Horn). Pyrethrum marc with 0.4% pyrethrins and cyfluthrin dust (0.1% a.i.) when applied on filter paper at 0.72 mg/cm2 gave 98.6% and 100% knockdown (KD) respectively after 6 h. Cyfluthrin dust had a faster KD effect with 100% KD compared to 93.1% for pyrethrum marc, ½1/2>h after treatment. After 24 h there was no recovery from KD in both treatments. After 72 h, 23.2% of the LGB had recovered from KD while mortality was 76.8% in the pyrethrum marc treatment. After the same period, cyfluthrin resulted in 100% mortality. Mortality of P. truncatus exposed to different dosages of cyfluthrin dust in shelled maize was less than 100% at dosages lower than 1 part per million (ppm) but was 100% at 1 ppm and higher dosages 3 days after treatment. Progeny emergence was suppressed at all dosage levels above 0.25 ppm compared to a mean progeny of 68.8 in the check after...

Electric arc furnace dust treatment

Electric arc furnace dust treatment

Effect of cement dust treatment on some phylloplane fungi of wheat

The percent frequency and number of colonies cm−2 leaf area of all the test fungi decreased significantly at the higher doses of cement dust during both pre- and post inoculation treatments. However, the population of some fungi increased at the low dose only. Stimulatory as well as inhibitory effect of cement dust on colony growth of the test fungi were observed at different concentrations of cement dust (500, 1000, 1500, and 2000 μm mL−1).

4711662 Process for the simultaneous treatment of dust, sludge and steel slag : Akihisa Harada, Kitakyushu, Japan assigned to Nippon Jiryoku Senko Co Ltd

4711662 Process for the simultaneous treatment of dust, sludge and steel slag : Akihisa Harada, Kitakyushu, Japan assigned to Nippon Jiryoku Senko Co Ltd

Control of seed‐borne Sclerotinia sclerotiorum by fungicidal treatment of sunflower seed

Treatment of sunflower seeds with benomyl, vinclozolin, iprodione or procymidone virtually eliminated seed‐borne Sclerotinia sclerotiorum. Applications of fungicides increased the number of surviving seedlings when seeds were sown in vermiculite or in steam‐sterilized soil. With the exception of benomyl, fungicides were significantly more effective when applied in acetone solutions than when 100 g a.i./100 kg of seed was applied as conventional dry dressings. There was no difference in effectiveness between the two application methods when the dry dressings were applied at 200 g a.i/100 kg of seed. The acetone infusion method had no deleterious effects on germination of disease‐free seed nor on seedling vigour. For a comparable level of control, less fungicide was needed in the infusion treatment than in the dust treatment. If fungicidal treatment of sunflower seeds is used routinely then the introduction of S. sclerotiorum into uninfested land could be controlled.