As part of the work, studies of the quality of wastewater from alcohol production were carried out; the main characteristics were determined, such as the charge of dispersed particles and the content of organic compounds and fats. A comparison is made of the effectiveness of titanium salts, traditional aluminum, and iron-containing coagulants. It has been established that titanium salts are much more effective than traditional reagents, but their high cost significantly limits the scope of their application. The possibility of increasing the efficiency of traditional coagulants by adding various titanium salts in an amount of up to 10% of the mass has been proved. It has been established that the addition of titanium compounds to aluminum or iron-containing coagulants makes it possible to increase the cleaning efficiency by an average of 10–20% while a significant reduction in the dose of reagents is possible, which will have a positive effect on the cost of the cleaning process. It was found that the addition of titanium salts to a coagulant based on aluminum sulfate allows not only an increase in the cleaning efficiency but also further intensifies the processes of sedimentation and filtration of coagulation sludge, which will significantly reduce the size of the treatment equipment and reduce capital costs.

DOI: 10.31897/PMI.2023.15 Leucoxene-quartz concentrate is a large-tonnage by-product of development of the Timan oil-titanium field (oil-saturated sandstones) which is not commercially used at present. High content of titanium compounds (to 50 % by weight) and lack of industrial, cost-effective, and safe technologies for its processing determine a high relevance of the...

In the course of the work, the quantitative and qualitative characteristics of the wastewater of the machine-building enterprises of the Moscow and Penza regions were investigated. It was found that in most cases the most difficult to remove contaminants are oil products entering the wastewater from metal processing operations, as well as heavy metal ions. Due to the lack of separation of stormwater, industrial and domestic sewage systems, the effluent under study had high concentrations of dissolved organic compounds (Biological Oxygen Demand BOD/chemical oxygen demand COD) and suspended solids. Laboratory tests of experimental samples of complex coagulant on waste water of real production were carried out. Normal aluminum sulfate and aluminum sulfate modified with hydrolysis products of titanium tetrachloride (complex coagulant) were used as reagents. It has been established that complex titanium-containing reagents are effective in the processes of coagulation sewage treatment of machine-building enterprises. The process of flocculation and sedimentation proceeded at a high rate due to flocculation reactions on the surface of titanium hydroxo-complexes, as well as nucleation phenomena on the surface of titanium hydroxide particles. The increased efficiency of samples modified by hydrolysis products of titanium coagulant compounds with respect to traditional aluminum sulfate has been proved. The consumption of complex coagulant compared with aluminum sulfate was about 1.25 - 1.5 times lower, while its efficiency is about 5 - 10% higher. The increased efficiency of complex coagulants with respect to the indicators of oil products, COD and color (organic pollutants) was noted, which is due to the developed adsorption surface of titanium hydroxide flakes in comparison with aluminum hydroxide.

The main goal of waste water treatment of metallurgical production is to return water to the circulating water supply system. The main pollutant of most process effluents are suspended substances, or suspensions. The key parameter for evaluating the cleaning efficiency is the residual content of suspended substances, which should not exceed 1–10 mg/l, depending on the technological purpose of the water. The most promising reagents for physic-chemical water treatment are complex coagulants that combine salts of two or more metals. Such reagents are free from the disadvantages of traditional coagulants, and large-scale wastes from various industries can be used as raw materials for their production. Complex coagulants based on aluminum salts, when aluminium is modified by the products of hydrolysis of titanium compounds, have proven to be highly effective in treatment processes of waste water of various origins. Testing of the complex coagulant obtained in the process of modifying of traditional aluminum sulfate by the products of hydrolysis of titanium compounds was carried out on waste water from gas cleaning plants for coal preparation, coking plants and electric arc furnaces for steelmaking. In terms of its effectiveness, the complex coagulant exceeded traditional aluminum sulfate and was as close as possible to the more expensive and modern aluminum oxychloride. The increased efficiency of the complex coagulant is due to flocculation and nucleation phenomena occurring on the surface of titanium compounds compared with aluminum sulfate. The complex coagulant was less sensitive to fluctuations in the pH of the treated water than pure aluminum sulfate. As a result of water treatment, it was possible to achieve a reduction in the content of suspended substances below 1 mg/l, which will positively affect the economy of the water treatment process. The rate of flake deposition and filtration of treated water, using complex coagulant, significantly exceeded both samples of the most common coagulants. Increased sediment density will reduce reagent costs for its dehydration, as well as the area required for its placement.

Setting up a circulation water supply system is a prerequisite for a modern competitive steel making company. The most frequent problem faced by steel makers includes the challenge of removing suspended solids from large volumes of waste-water. Residual concentration of suspended solids (1-10 mg/l) is the main criterion of treatment efficiency. The most difficult task is to remove particles smaller than 1-2 microns, which stay suspended for a long time. One of the biggest sources of wastewater includes the process of removing residual molding sand from machine parts by water jet surface cleaning. Apart from high concentrations of suspended solids, process wastewater have high concentrations of dissolved organic compounds and require prior treatment before it can go to municipal wastewater treatment plants. Titanium-containing coagulants are being used more and more commonly in water treatment processes due to their high efficiency and the lack of most of the drawbacks inherent in conventional coagulants. This paper compares the conventional coagulants (i.e. aluminum and iron compounds) and coagulants containing titanium salts. In addition, complex titanium-containing coagulants were tested in the actual process of removing residual molding sand from machine parts by water jet surface cleaning. The findings show that titanium tetrachloride outperforms the conventionally used aluminum sulphate and iron chloride, while the effective dose of titanium tetrachloride is on average 2.5 to 3.0 times smaller. The obtained experimental data characterize the effect of added titanium compounds on the water treatment efficiency when conventional reagents are used. It was found that the addition 7.5 wt% of titanium tetrachloride to the conventional aluminum sulphate increases the treatment performance of the latter by 30%. The high efficiency of titanium-containing reagents is due to specific hydrolysis effects, as well as nucleation and flocculation at the surface of hydrolysis products. The rate of sedimentation and filtration of sludges resultant from water treatment with titanium-containing coagulants significantly exceeded that reached when using conventional reagents. The use of titanium-containing reagents will enable to transfer to smaller settlers and filters, reduce the consumption of reagents and reach an enhanced treatment performance. The treated water can be reused or discharged into municipal sewage treatment plants.

Quartz-leucoxene ore and its processing concentrates are valuable titanium-containing raw materials, however a comprehensive processing technology for the ore is yet to be developed. This paper studies the high-temperature processes occurring in a system containing quartz-leucoxene concentrate with an iron-containing additive. It has been established that, depending on the atmosphere of the pyrometallurgical processing and the type of the iron-containing additive, phases of ilmenite (in an inert atmosphere) or pseudobrookite (in an oxidizing atmosphere) may be obtained. The possibility of using heat treatment and forging scale (a common large-tonnage metallurgical production waste) as an iron-containing additive has been studied. It has been established that pseudobrookite will be the final product. For all concentrate/iron-containing additive systems studied, depending on the thermal effects, the possibility of intermediate reduction/oxidation reactions for iron oxides and of the formation of Fe2TiO4 intermediate phases (followed by their transition to the pseudobrookite phase) was identified. The minimum triggering temperatures for the conversion process of quartz-leucoxene concentrate Fe2TiO5 and FeTiO3 have been established, as well as the main thermal effects, mass losses, and melt crystallization parameters, which allows optimizing the conditions for pyrometallurgical conversion. The data obtained enables effective process scaling. It has been established that impurity components in the concentrate (up to 7–9 wt% on average) enter into intrasystem reactions with the formation of calcium titanates (sphene CaSiTiO5) and magnesium (MgTiO3, MgTi2O5, Mg2TiO2).This is a continuation of the article titled «Principles of pyro-hydrometallurgical processing of quartz-leucoxene concentrates with the formation of a pseudobrookite phase» («Obogashchenie Rud», 2021, No. 3).